Normative Computed Tomography Angiography Values of the Aortic Root, Aorta and Aortic arch in Children

Normative Computed Tomography Angiography Values of the Aortic Root, Aorta and Aortic arch in Children | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Normative Computed Tomography Angiography Values of the Aortic Root, Aorta and Aortic arch in Children Rakesh Donthula, Wen Li, Archita Duvvada, Dan Dyer, Santosh C. Uppu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4406785/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Normative values for intracardiac and extracardiac vascular structures help in understanding normal growth and changes over time in children; this normative data are not currently available for ECG-gated Computed Tomography Angiography (CTA). We sought to establish ECG-gated CTA derived normative values for the aortic root, aorta and aortic arch in children. Methods and Results Aortic root, ascending aorta, aortic arch, and descending aorta were measured in systole and diastole in 100 subjects who had ECG-gated CTA at our center between January 2015 through December 2020 and met our inclusion criteria. The allometric exponent (AE) for each parameter was derived, and the parameter/body surface area AE (BSA AE ) was established using the previously described methods. Using this data, normalized mean, cross-sectional area, and standard deviation were calculated. Z-score curves were plotted in relation to the BSA for all measurements. Conclusion Our study reports systolic and diastolic ECG-gated CTA Z-scores along with normative curves in relation to BSA for the aortic root, aorta and aortic arch in children. Computed Tomography Angiography Z-scores Normative values Pediatrics Aorta Aortic root Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction Overall survival and outcomes have improved in patients with congenital heart disease due to significant advances in the diagnosis, management, and treatment 1 2 . Cardiac imaging including echocardiography (echo), cardiac ECG-gated computed tomography angiography (CTA), and cardiac Magnetic resonance imaging (CMR) play a vital role in the diagnosis and follow-up of patients with congenital heart defects and patients with connective tissue disease (Marfan, Ehler-Danlos, Loeys-Dietz syndrome etc) 3 4 5 6 7 . Normative data for intracardiac and extracardiac vascular structures in the pediatric population are available for echo, CMR and non ECG-gated CTA 8 9 10 11 . As a result, imagers tend to interpret the CTA aortic measurements with known echo or CMR normative data, this is not ideal due to the inherent variation of the imaging modalities. The utility of CTA is gaining acceptance in pediatric cardiology with improvements in scanning techniques, advances in radiation reduction, ease of access, and its ability to limit anesthesia exposure in young children due to fast scan times 6,12 . Cross-sectional imaging with CTA and CMR has added benefit in advanced planning for interventional procedures, creation of virtual or 3D models, overlaying with angiography to reduce radiation dose during an intervention, etc 13–16 . En face measurements using double oblique technique derived from cross-sectional imaging are made to report major and minor dimensions for a structure which negates the assumption that a vascular structure has a circular profile 17 . Somatic growth should be considered for the pediatric population. For that reason, Z-scores are commonly used with standard deviations (SD) above and below a given measurement, but SDs are not constant across body sizes due to heteroscedasticity adding further complexity to the interpretation. Prior studies have attempted to report non-ECG gated CT diameters of aortic structures 18–20 . We have previously published normative ECG-gated CT Z-scores for the main and branch pulmonary arteries 21 . In this study, we sought to establish ECG-gated CTA-derived normative values and Z-scores for the aortic root and aorta in children. Methods Data Sources: The study was approved by our institutional review board (The University of Texas Health Science Center at Houston and Memorial Hermann, (HSC-MS-20-1338, September 13 th, 2021) and waived the need for informed consent. We conducted a retrospective chart review including all consecutive patients less than 18 years of age who underwent ECG-gated- cardiac CTA between January 2015 and December 2020. We identified subjects using our imaging database and electronic medical records. Inpatient and outpatient records were analyzed to obtain baseline information. Population: All children less than or equal to 18 years of age, who underwent ECG-gated cardiac CTA at our institution from January 2015 to December 2020 who met the inclusion criteria as listed in Table 1 were identified, those meeting the exclusion criteria were removed from the final analysis. The diagnosis and indication of the CTA for the included subjects are listed in Table 2 . As cardiac CTA is not routinely performed in normal subjects, we broadly defined subjects without cardiac involvement as “normal”. Children with vascular rings (double aortic and right aortic arches) were also included in this study. For vascular ring subjects only the aortic root, ascending aorta and descending abdominal aortic measurements away from the vascular ring were recorded as normal, in this way we avoided the area of pathology. As such the number of subjects has been lower compared to an echo or CMR study with similar goals 22,23 . Table 1 Inclusion and exclusion criteria Inclusion Criteria Exclusion Criteria ● Age ≤ 18 years of age ● Structurally normal heart ● Vascular ring ● Anomalous aortic origin of the coronary artery ● Small patent ductus arteriosus in age < 1-month ● Small patent foramen ovale ● Any CHD other than listed in the inclusion criteria. ● Aortic valve disease ● Diagnosed connective tissue disorder (Marfan, Ehler-Danlos, etc.) ● Rheumatic heart disease ● Depressed ventricular function by echocardiogram ● Dilated cardiac chambers by echocardiogram ● Motor vehicle accident with cardiac involvement ● Motion artifact on the CT scan ● History of cardiac surgery/intervention CHD- Congenital Heart Defect Table 2 Diagnosis of included subjects. Diagnosis Number (Total N = 100) Structurally normal heart 29 Anomalous Aortic origin of coronary arteries RCA ( 16 ), LCA ( 3 ) Double aortic arch 13 Right aortic arch with aberrant left subclavian artery 25 Kawasaki disease follow-up with no coronary involvement, normal function 3 Others 9 * RCA- Anomalous aortic origin of the right coronary artery, LCA- Anomalous aortic origin of the left coronary artery. Patient selection, preparation, and contrast medium: All patients were referred to our imaging center by a pediatric cardiologist for further evaluation. An initial screen was performed by an attending imaging cardiologist prior to cardiac CTA after reviewing echocardiographic information, patient medical records, and available clinical and diagnostic information. Those deemed candidates for CTA followed our institutional imaging protocol. Subjects younger than 6 weeks often underwent feed and swaddle techniques to minimize the need for sedation. Subjects between 6 weeks and 6 years were individualized based on the imaging goal, if anesthesia was needed, deep sedation without intubation was preferred for subjects with vascular rings. In subjects with a feed and swaddle approach image acquisition and timing were geared toward the clinical question. Some of these subjects had diagnostic studies but the image quality may not have been adequate for our study purpose as such they were excluded. Subjects less than 6 years requiring coronary artery evaluation were often anesthetized and intubated for better heart rate and respiratory control to avoid motion artifacts 24 . The location of the peripheral intravenous (PIV) access was determined by the imaging question. To evaluate for the aortic arch abnormalities, a foot PIV was preferred for contrast injection. Iso-osmolar, nonionic, and water‐soluble agents (Iodixanol, Visipaque™ 320 mg iodine/ml) were used for all the examinations 25 . The total contrast dose was 1.5–2 ml/kg of body weight. The contrast medium was administered using a dual‐head power injector at an injection rate of 0.8–1.2 ml/s for a 24G PIV. The injection rate is increased based on the size of the PIV up to 4-6.5 ml/s 12,26 . A bolus of isotonic saline solution was administered after contrast to reduce high-density contrast (streak) artifact. Automated bolus tracking technique was used with reference cardiovascular structure being monitored at near real-time until predetermined threshold opacification of 120–150 Hounsfield units was achieved at reference level. A scan delay of 4–5 seconds was often used for image acquisition 27 . Cardiac CTA technique: During the study period, different generations of Siemens CT scanners were used to perform these studies. These include SOMATOM AS 128, SOMATOM definition edge, and SOMATOM Force Dual-source CT (Siemens Healthineers). Studies were performed according to our institutional protocol using a tube voltage of 70–100 kV and tube current auto modulation (CareDose4D, Siemens Healthineers), a slice thickness of 0.6 mm 9,26,28 . Retrospective electrocardiography (ECG)-gated acquisition was performed when ventricular volume/function and coronary artery evaluation were needed. The prospective ECG‐triggered technique was used to delineate vascular anatomy 11 . Images were reconstructed with a slice thickness of 0.6 mm and an increment of 0.4–0.6 mm 29 . Images acquired when the aortic valve was open were included under systole, usually between 30 and 40% RR interval. and the images acquired during 70–80% RR interval were included under diastole. Subjects who underwent retrospectively ECG-gated CTA had both systolic and diastolic images. Prospectively ECG-gated CTA images were acquired either in systole or diastole based on the subject’s heart rate as per the machine algorithm and imager preference to minimize motion artifact. All studies were performed with an imaging cardiologist present during the scan. Image Post-processing : All measurements were performed on a cardiovascular imaging workstation (Circle CVI42; Circle Cardiovascular Imaging Inc. Alberta, Canada) after studies were anonymized. All images were visualized in axial, sagittal, and coronal planes with a window (600–900) and a level (250–350) settings. Double oblique planes using multiplanar reformatting were performed to measure aortic root, sinotubular junction (STJ), ascending aorta (AAO) at the level of the branch pulmonary artery, proximal (PTA) and distal transverse arch (DTA), aortic isthmus (IS), and descending aorta (DAO) at the level of the diaphragm 17,18,30 . As mentioned arch measurements for vascular ring subjects were not performed to avoid errors. Maximum, minimum, and mean diameters and cross-sectional area are measured for all the parameters except for the aortic root. (Fig. 1). For the aortic root, three measurements were made at mid- sinus level at their maximum dimensions. Cusps were named by the expected coronary artery origin, and commissures go along with them 31 . Aortic root measurements for this study are named as follows (Fig. 2). A- Right cusp to left/non-coronary commissure diameter B- Left cusp to non-coronary/right commissure diameter C- Non-coronary cusp to right/left commissure diameter. The measurements were categorized as either systole or diastole as described above. Aortic measurements were performed at the following levels: ascending aorta was measured at the level of the right pulmonary artery/ bifurcation of pulmonary arteries 18,20 , proximal transverse arch was measured immediately after the first branch of aorta, distal transverse arch was measured before the left subclavian artery, isthmus was measured after the last aortic branch. Descending Aorta was measured at the level of the diaphragm 18 . Statistical analysis: Data was expressed as mean ± SD. The measure of the vessel was indexed to the body surface area (BSA) according to the Haycock formula 32 . The allometric exponent for each parameter was derived by applying the ordinary least squares method in which the natural logarithm of the parameter was regressed on the natural logarithm of BSA 33,34 . This method allows for a nonlinear relationship between the parameter and BSA. Specifically, the following steps were used. 1. The equation Y = mX b was considered to decide the potentially nonlinear relationship between a parameter and BSA. Y denoted the parameter, X denoted BSA, and b was the AE to be estimated. 2. After taking the natural log, a linear regression formula was obtained: ln(Y) = ln(m) + bln(X) , where ln(Y) was the dependent variable and ln(X) was the independent variable. 3. The regression coefficient estimate \(\widehat{b}\) for \(b\) from the least squares method was the derived AE. We then indexed the parameter using BSA to the power of the derived AE. We did the following quality check to make sure that the allometric model was adequate and that there was no residual relationship between the indexed parameter and BSA. The indexed parameter was regressed against BSA. The regression line was plotted, and R 2 was calculated. A flat line and a small R 2 indicate no residual relationship. Pearson correlation coefficient and the corresponding P value were determined. A correlation close to zero and a P-value ≥ 0.05 also indicate no residual relationship. We checked the normality of the indexed parameter using the Shapiro–Wilk test and reported µ ± \(\sigma\) where µ and \(\sigma\) denoted the mean and SD of the indexed parameter. Last, we plotted non-indexed parameters against BSA with lines representing the mean, ± 1, ± 2, and ± 3 SDs of the mean based on the relationship that the non-indexed parameter followed a normal distribution with a mean of µBSA AE and SD of BSA AE . Interobserver and intraobserver variability were assessed using the intraclass correlation coefficient in a subset of 50 subjects. All analyses were conducted using R version 4.0.5 (March 2021). Results Patient characteristics: Out of 628 patients who underwent CTA at our institution during the study period, 100 children met the inclusion criteria and were analyzed. The mean age and BSA of the subjects were 5.3 ± 6.1 years (range 0–18 years) and 0.8 ± 0.68 m 2 (range 0.16–2.8 m 2 ) respectively. Among the subjects, 56% were male (Table 3 ). The majority (71%) of our subjects were young with a BSA < 1 m 2 . The most common finding on the CTA was structurally normal heart (n = 29), followed by right aortic arch with aberrant left subclavian artery (n = 25), and coronary anomaly (n = 21) as shown in Table 2 . Table 3 Demographics Sex (%) Male (56%) 71% BSA < 1 m 2 Mean (SD) Median (range) Age 5.3 yrs (6.1) 2.3 yrs (0–18) Weight 26.2 Kg (31.4) 12.75 Kg (2.04–156) Height 98 cm (47.8) 88.5 cm (44–187) BSA 0.8 m 2 (0.68) 0.6 m 2 (0.16–2.8) BSA - body surface area, SD - standard deviation Systolic measurements for aortic root, STJ, AAO and DAO were available in the majority of our subjects (n > 77). Systolic IS and DTA measurements were available in 50 subjects. Systolic PTA measurement was available in very few subjects (n = 35) due to common origin of the innominate and left carotid artery (n = 15). The Diastolic measurements were available in fewer subjects (root = 37, STJ = 41, AAO = 47, PTA = 25, DTA = 34, IS = 34 and DAO = 49 respectively) due to the younger age of our study population the CTA imaging protocols are geared towards acquiring the image during the least heart motion to reduce artifacts. As such systolic imaging was common in young children due to fast heart rates. Normative values: The normalized mean diameters (mm), cross-sectional area (mm 2 ), and standard deviation in systole and diastole are shown in Tables 4 , 5 . Based on the results in these tables, we can calculate the Z-score of a measurement for a given BSA using the reported AE, mean, and SD of that parameter: Table 4 Maximum, minimum, mean, and area variables with AE, SD in systole. Systolic parameter n AE mean Standard Deviation Ascending Aorta Max 88 0.49 18.236 2.079 Ascending Aorta Min 88 0.51 17.398 2.118 Ascending Aorta Mean 88 0.5 17.817 2.069 Ascending Aorta Area 88 1 252.409 59.336 Aortic STJ Max 79 0.5 17.842 1.649 Aortic STJ Min 79 0.49 16.952 1.674 Aortic STJ Mean 79 0.5 17.398 1.625 Aortic STJ Area 79 0.99 239.495 45.584 Aortic root A 77 0.49 19.021 1.929 Aortic root B 77 0.47 20.029 1.85 Aortic root C 77 0.47 20.221 2.151 Aortic root Mean 77 0.48 19.757 1.847 Descending Aorta Max 94 0.42 12.704 1.501 Descending Aorta Min 94 0.43 12.234 1.497 Descending Aorta Mean 94 0.43 12.469 1.48 Descending Aorta Area 94 0.85 123.719 29.275 Isthmus Max 50 0.56 14.706 1.777 Isthmus Min 50 0.56 13.795 1.637 Isthmus Mean 50 0.56 14.251 1.688 Isthmus Area 50 1.11 161.471 38.26 Proximal Transverse arch Max 35 0.47 17.233 2.348 Proximal transverse arch Min 35 0.49 15.625 1.898 Proximal transverse arch Mean 35 0.48 16.43 1.977 Proximal transverse arch Area 35 0.95 213.975 50.953 Distal Transverse arch Max 50 0.54 15.891 1.874 Distal Transverse arch Min 50 0.53 14.777 1.716 Distal Transverse arch Mean 50 0.53 15.334 1.725 Distal Transverse arch Area 50 1.07 186.513 41.694 Max - maximum diameter, Min - minimum diameter, Mean - mean diameter, area - cross-sectional area, N - number of subjects, AE - allometric exponent, SD- standard deviation. Max, Min, and Mean diameters are reported in millimeters, cross-sectional area is reported in square millimeters. STJ - sinotubular junction. Aortic root: A- Right cusp to left/non-coronary commissure, B- Left cusp to non-coronary/right commissure, C- Non-coronary cusp to right/left commissure. Table 5 Maximum, minimum, mean, area variables with AE, SD in diastole. Diastolic parameter n AE mean Standard Deviation Ascending Aorta Max 47 0.51 16.646 1.945 Ascending Aorta Min 47 0.51 15.82 1.747 Ascending Aorta Mean 47 0.51 16.233 1.816 Ascending Aorta Area 47 1.02 209.257 48.028 Aortic STJ Max 41 0.51 16.773 1.79 Aortic STJ Min 41 0.51 15.979 1.696 Aortic STJ Mean 41 0.51 16.376 1.715 Aortic STJ Area 41 1.01 212.678 45.333 Aortic root A 37 0.51 17.759 1.746 Aortic root B 37 0.5 19.323 1.857 Aortic root C 37 0.51 19.416 1.785 Aortic root Mean 37 0.5 18.833 1.673 Descending Aorta Max 49 0.42 11.902 1.358 Descending Aorta Min 49 0.42 11.463 1.229 Descending Aorta Mean 49 0.42 11.682 1.271 Descending Aorta Area 49 0.84 108.346 23.556 Isthmus Max 34 0.55 13.71 1.595 Isthmus Min 34 0.57 12.809 1.636 Isthmus Mean 34 0.56 13.26 1.576 Isthmus Area 34 1.13 139.727 32.264 Proximal Transverse arch Max 25 0.44 15.624 1.967 Proximal Transverse arch Min 25 0.48 14.14 2.105 Proximal Transverse arch Mean 25 0.45 14.885 1.982 Proximal Transverse arch Area 25 0.91 176.293 47.642 Distal Transverse arch Max 34 0.52 14.687 1.871 Distal Transverse arch Min 34 0.52 13.744 1.761 Distal Transverse arch Mean 34 0.52 14.216 1.775 Distal Transverse arch Area 34 1.04 160.828 40.149 Max- maximum diameter, Min- minimum diameter, Mean - mean diameter, area - cross-sectional area, N- number of subjects, AE - allometric exponent, SD- standard deviation. Max, Min, and Mean diameters are reported in millimeters, cross-sectional area is reported in square millimeters. STJ - sinotubular junction, STJ - sinotubular junction. Aortic root: A- Right cusp to left/non-coronary commissure, B- Left cusp to non-coronary/right commissure, C- Non-coronary cusp to right/left commissure. $$Z-score = \frac{indexed value– \mu }{\sigma }$$ , where $$indexed value = \frac{measure{d}_{ }value}{BS{A}^{AE}}$$ , µ denotes the mean of the indexed parameter, and \(\sigma\) denotes the SD of the indexed parameter as described in the statistical analysis section. For example, if a subject has an Ascending Aorta Maximum in systole measurement of 17.44 mm and a BSA of 0.6 m 2 , we can derive the Z-score by plugging in the numbers (AE = 0.49, mean = 18.236, SD = 2.079) to the above equations. That is, \(indexed value = \frac{17.44}{{0.6}^{0.49}}=22.40\) , and \(Z-score = \frac{22.40–18.236 }{2.079}=2.00\) . The Z-score plots for systolic and diastolic aortic root diameters and their means are shown in Figs. 3, and 4. The Z-score plots for systolic and diastolic diameters, mean diameters and cross-sectional areas of the aortic structures are shown in Figs. 5, 6, 7 and 8 respectively. As expected systolic diameters were 6–11% larger and systolic cross-sectional areas were 13–20% larger compared to diastolic measures. Aortic root systolic measures were 5% larger than the diastolic measures. Reproducibility: There was an excellent inter and intraobserver agreement (> 0.92) for both systolic and diastolic measurements (Tables 6 , 7 ) indicating excellent reproducibility of our method. Table 6 Inter and intraobserver variability for parameters in systole. Systole variables intra-rater 95% CI inter-rater 95% CI Ascending Aorta Max 0.978 (0.947, 0.991) 0.983 (0.95, 0.994) Ascending Aorta Min 0.989 (0.973, 0.995) 0.985 (0.956, 0.995) Ascending Aorta Mean 0.99 (0.975, 0.996) 0.987 (0.964, 0.996) Aortic STJ Max 0.989 (0.973, 0.996) 0.975 (0.927, 0.992) Aortic STJ Min 0.987 (0.967, 0.995) 0.991 (0.974, 0.997) Aortic STJ Mean 0.983 (0.957, 0.993) 0.988 (0.963, 0.996) Aortic root A 0.984 (0.958, 0.994) 0.978 (0.936, 0.993) Aortic root B 0.982 (0.953, 0.994) 0.982 (0.946, 0.994) Aortic root C 0.991 (0.977, 0.997) 0.99 (0.971, 0.997) Aortic root Mean 0.994 (0.983, 0.998) 0.99 (0.969, 0.997) Descending Aorta Max 0.968 (0.923, 0.987) 0.975 (0.93, 0.992) Descending Aorta Min 0.925 (0.819, 0.97) 0.978 (0.938, 0.992) Descending Aorta Mean 0.97 (0.925, 0.988) 0.981 (0.946, 0.994) Isthmus Max 0.995 (0.981, 0.999) 0.991 (0.945, 0.999) Isthmus Min 0.989 (0.956, 0.997) 0.983 (0.903, 0.998) Isthmus Mean 0.996 (0.985, 0.999) 0.991 (0.948, 0.999) Proximal Transverse arch Max 0.92 (0.599, 0.988) 0.895 (0.287, 0.993) Proximal transverse arch Min 0.986 (0.92, 0.998) 0.983 (0.843, 0.999) Proximal transverse arch Mean 0.967 (0.819, 0.995) 0.956 (0.634, 0.997) Distal Transverse arch Max 0.967 (0.871, 0.992) 0.964 (0.803, 0.995) Distal Transverse arch Min 0.984 (0.934, 0.996) 0.983 (0.904, 0.998) Distal Transverse arch Mean 0.978 (0.913, 0.995) 0.977 (0.868, 0.997) Max- maximum diameter, Min- minimum diameter, Mean - mean diameter, STJ - sinotubular junction, STJ - sinotubular junction. Aortic root: A- Right cusp to left/non-coronary commissure, B- Left cusp to non-coronary/right commissure, C- Non-coronary cusp to right/left commissure. CI - confidence interval. Table 7 Inter and intraobserver variability for parameters in diastole. Diastole variables intra-rater 95% CI inter-rater 95% CI Ascending Aorta Max 0.995 (0.983, 0.999) 0.986 (0.952, 0.996) Ascending Aorta Min 0.986 (0.955, 0.996) 0.987 (0.957, 0.997) Ascending Aorta Mean 0.994 (0.979, 0.998) 0.993 (0.975, 0.998) Aortic STJ Max 0.98 (0.925, 0.995) 0.969 (0.88, 0.993) Aortic STJ Min 0.988 (0.956, 0.997) 0.979 (0.918, 0.995) Aortic STJ Mean 0.988 (0.955, 0.997) 0.981 (0.923, 0.996) Aortic root A 0.966 (0.838, 0.994) 0.94 (0.688, 0.991) Aortic root B 0.968 (0.849, 0.994) 0.965 (0.808, 0.995) Aortic root C 0.986 (0.93, 0.998) 0.976 (0.863, 0.996) Aortic root Mean 0.98 (0.904, 0.997) 0.971 (0.836, 0.996) Descending Aorta Max 0.91 (0.715, 0.975) 0.868 (0.579, 0.965) Descending Aorta Min 0.959 (0.862, 0.989) 0.948 (0.817, 0.987) Descending Aorta Mean 0.943 (0.813, 0.984) 0.922 (0.734, 0.98) Isthmus Max 0.983 (0.903, 0.998) 0.981 (0.869, 0.998) Isthmus Min 0.982 (0.899, 0.997) 0.979 (0.851, 0.998) Isthmus Mean 0.983 (0.903, 0.998) 0.984 (0.889, 0.998) Proximal Transverse arch Max 0.949 (0.677, 0.994) 0.961 (0.666, 0.997) Proximal Transverse arch Min 0.982 (0.877, 0.998) 0.986 (0.87, 0.999) Proximal Transverse arch Mean 0.969 (0.792, 0.997) 0.981 (0.825, 0.999) Distal Transverse arch Max 0.985 (0.913, 0.998) 0.997 (0.975, 1) Distal Transverse arch Min 0.994 (0.962, 0.999) 0.996 (0.969, 1) Distal Transverse arch Mean 0.996 (0.975, 0.999) 0.997 (0.975, 1) Max- maximum diameter, Min- minimum diameter, Mean - mean diameter, STJ - sinotubular junction, STJ - sinotubular junction. Aortic root: A- Right cusp to left/non-coronary commissure, B- Left cusp to non-coronary/right commissure, C- Non-coronary cusp to right/left commissure. CI - confidence interval. Discussion We report normative systolic, diastolic diameters, cross sectional areas along with Z-scores and normative curves for the aorta, aortic root and aortic arch for ECG-gated cardiac CTA in children younger than 18 years. We report maximum, minimum, and mean diameters as well as the cross-sectional areas for these structures. Normative values in children exist for echo, CMR, and non ECG -gated CTA but are lacking for ECG-gated- CTA 35–37 . Few non-ECG-gated CTA studies reported normative measurements so far. Akay et al. 20 used single axial measurement with respect to patient age, sex and T- vertebral body size. Bayindir et al. 19 used single measurements from standard axial imaging planes as well. These measurements did not take the patient size into account; as such, the influence of growth and body size in a patient cannot be assessed. This methodology can also be challenging especially in patients with congenital heart defects, heterotaxy, etc. where a single-plane measurement may not be practical. Hegde et al. 18 reported aortic measurements using the double-oblique method using CTAs performed mostly in oncology, chest pain and trauma patients (42%, 16% and 10% respectively); their measurement technique was similar to our study. However, they have not reported cross sectional areas or used ECG-gated CTAs which the authors have recognized as a limitation. Their data was modeled using a natural log-transformed response variable. En face measurements of the aorta provide an accurate assessment of the structure of interest 17 . Cardiac CTA is gaining acceptance in congenital cardiology to better evaluate vascular structures due to the improvements in scanning techniques, radiation reduction, ease of access, fast scan times, and reduced need for anesthesia in young children 6,28 . Our study is also unique in reporting both systolic and diastolic normative aortic values; our study confirms larger systolic parameters compared with diastolic measures as was previously described by an angiographic study 38 . The cross-sectional area along with the mean diameter may have real-world applicability as the structure of interest can be assessed in any non-standard plane. This is especially important in patients with congenital heart defects where a vascular structure may not be in a normal orientation. Deriving normative values and Z-scores can be achieved by various methods and there is significant variation among Z-scores derived from each method 39–42 . We chose the previously described and validated method of using BSA as an expression of body size and linear regression for the relationship between body growth and cardiovascular dimensions 43,44 21,33,45–47 . Cardiovascular allometry is defined as the relative growth of cardiac structure in relation to somatic growth. Identifying a correct allometric relationship and model for a structure is important for its interpretation and clinical application 34,43 . Multiple authors have advocated the use of an allometric model to identify a true indexing method of a physiologically dependent variable and this method has been widely used for various echo Z-score calculators that are in current clinical use 33–35,43,44 . Recruiting normal children for a CTA study is ethically not possible due to radiation exposure, need for sedation/anesthesia, and contrast use. It is not uncommon to identify normal subjects who undergo cross-sectional imaging for various reasons to be included in a study. Prior CMR and CTA studies to derive normative values for the aorta and pulmonary arteries have included children with a history of malignancy 22,23 . We have been diligent to include subjects with normal cardiac anatomy, as a result, this data should be close to what is expected for a normal population. Future studies are needed to validate our results with a larger sample. We plan to make our data publicly available. Limitations: Our single-center, small-sample, retrospective study has inherent limitations due to its design. Generalized applicability across institutions may not be possible, but there is a lack of normative ECG-gated-CTA data available at this time. Our data will help kick-start the process of performing a similar study in a multicenter fashion which can help address issues related to a single-center design. Similar goals have been achieved by the Pediatric Heart Network echocardiogram database that published echocardiographic Z-scores, although normative echo Z-scores have been in existence for a few decades. The statistical methodology may have issues with the model of choice, there has been extensive literature on various Z-score models but we felt that our approach is ideal for this study based on extensive prior experience using allometric models in echocardiographic Z-score studies. Our study population was mostly young with 71% having a BSA of less than 1 m 2 , this resulted in less subjects available for the diastolic measurements as the CTA protocols were geared to acquire during systole. We have not reported aortic annulus, descending thoracic aortic measurements, we feel that the abdominal aortic measurements have more clinical significance. Our study has not explored the influence of sex, or race on the Z-scores due to the small sample size, a multicenter design is likely to address this issue. Our sample has predominantly young children, its applicability to older children and adolescents should be done with caution. Conclusions This is the first pediatric study to report en face normative diameters and cross-sectional areas of the aortic root, ascending aorta and aortic arch in systole and diastole derived using ECG-gated cardiac CTA. This data has potential application for proper diagnosis, risk stratification, surgical planning, and planning catheter-related interventions for children with congenital heart defects and connective tissue disorders. The real-world applicability of this tool needs careful validation. Declarations Funding: Dr. Wen Li’s effort is supported by UL1TR003167. The other authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Competing Interests: The authors have no relevant financial or non-financial interests to disclose. Author Contributions: All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Rakesh Donthula and Santosh Uppu. Statistical analysis was performed by Wen Li. The first draft of the manuscript was written by Rakesh Donthula and Santosh Uppu. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Conference Presentation: The abstract was presented at the American Heart Association conference in Chicago, IL on November 5th, 2022. Ethical standards: This study was approved by The University of Texas Health Science Center at Houston and Memorial Hermann Institutional Review Board (HSC-MS-20-1338, September 13 th, 2021) and waived the need for informed consent. All human studies at the University of Texas at Houston Health Science Center and Memorial Hermann hospital have to go through rigorous review by the ethics committee and have therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinkiand its later amendments. The subjects were deidentified as per our IRB guidelines. Due to the retrospective nature, this study does not require contacting subjects as such a waiver of consent was requested and was approved by the IRB. References Marelli AJ, Ionescu-Ittu R, Mackie AS, Guo L, Dendukuri N, Kaouache M. Lifetime prevalence of congenital heart disease in the general population from 2000 to 2010. Circulation . 2014;130(9):749-756. doi:10.1161/CIRCULATIONAHA.113.008396 Gilboa SM, Devine OJ, Kucik JE, et al. Congenital heart defects in the united states: estimating the magnitude of the affected population in 2010. 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Geometry and dimensions of the pulmonary artery bifurcation in children and adolescents: assessment in vivo by contrast-enhanced MR-angiography. Int J Cardiovasc Imaging . 2011;27(3):385-396. doi:10.1007/s10554-010-9672-6 Kaiser T, Kellenberger CJ, Albisetti M, Bergsträsser E, Valsangiacomo Buechel ER. Normal values for aortic diameters in children and adolescents--assessment in vivo by contrast-enhanced CMR-angiography. J Cardiovasc Magn Reson . 2008;10:56. doi:10.1186/1532-429X-10-56 Husmann L, Herzog BA, Pazhenkottil AP, et al. Lowering heart rate with an optimised breathing protocol for prospectively ECG-triggered CT coronary angiography. Br J Radiol . 2011;84(1005):790-795. doi:10.1259/bjr/29696915 Spencer CM, Goa KL. Iodixanol. A review of its pharmacodynamic and pharmacokinetic properties and diagnostic use as an x-ray contrast medium. Drugs . 1996;52(6):899-927. doi:10.2165/00003495-199652060-00013 Uppu SC. Left ventricular outflow tract: In: Adebo DA, ed. Pediatric Cardiac CT in Congenital Heart Disease . Springer International Publishing; 2021:107-113. doi:10.1007/978-3-030-74822-7_15 Adebo DA. Techniques of Cardiac CT Scan: Patient Preparation, Contrast Medium, Scanning, and Post-Processing. In: Adebo DA, ed. Pediatric Cardiac CT in Congenital Heart Disease . Springer International Publishing; 2021:15-22. doi:10.1007/978-3-030-74822-7_2 Dodge-Khatami J, Adebo DA. Evaluation of complex congenital heart disease in infants using low dose cardiac computed tomography. Int J Cardiovasc Imaging . 2021;37(4):1455-1460. doi:10.1007/s10554-020-02118-7 Alshipli M, Kabir NA. Effect of slice thickness on image noise and diagnostic content of single-source-dual energy computed tomography. J Phys: Conf Ser . 2017;851:012005. doi:10.1088/1742-6596/851/1/012005 Bell D, Fortin F. Multiplanar reformation (MPR). In: Radiopaedia.Org . Radiopaedia.org; 2005. doi:10.53347/rID-65727 Leong K, Knipe H, Binny S, et al. Aortic root measurement on CT: linear dimensions, aortic root area and comparison with echocardiography. A retrospective cross sectional study. Br J Radiol . 2021;94(1121):20201232. doi:10.1259/bjr.20201232 Nevill AM, Bate S, Holder RL. Modeling physiological and anthropometric variables known to vary with body size and other confounding variables. Am J Phys Anthropol . 2005;Suppl 41:141-153. doi:10.1002/ajpa.20356 Bhatla P, Nielsen JC, Ko HH, Doucette J, Lytrivi ID, Srivastava S. Normal values of left atrial volume in pediatric age group using a validated allometric model. Circ Cardiovasc Imaging . 2012;5(6):791-796. doi:10.1161/CIRCIMAGING.112.974428 Rajagopal H, Uppu SC, Weigand J, et al. Validation of Right Atrial Area as a Measure of Right Atrial Size and Normal Values of in Healthy Pediatric Population by Two-Dimensional Echocardiography. Pediatr Cardiol . 2018;39(5):892-901. doi:10.1007/s00246-018-1838-3 Lopez L, Colan S, Stylianou M, et al. Relationship of echocardiographic Z scores adjusted for body surface area to age, sex, race, and ethnicity: the pediatric heart network normal echocardiogram database. Circ Cardiovasc Imaging . 2017;10(11). doi:10.1161/CIRCIMAGING.117.006979 Lopez L, Frommelt PC, Colan SD, et al. Pediatric Heart Network Echocardiographic Z Scores: Comparison with Other Published Models. J Am Soc Echocardiogr . 2021;34(2):185-192. doi:10.1016/j.echo.2020.09.019 Voges I, Giordano R, Koestenberg M, et al. Nomograms for cardiovascular magnetic resonance measurements in the pediatric age group: to define the normal and the expected abnormal values in corrected/palliated congenital heart disease: A systematic review. J Magn Reson Imaging . 2019;49(5):1222-1235. doi:10.1002/jmri.26614 Rammos S, Kramer HH, Trampisch HJ, Krogmann ON, Kozlik R, Bourgeois M. [Normal values of the growth of the pulmonary arteries in children. An angiography study]. Herz . 1989;14(6):348-357. Chubb H, Simpson JM. The use of Z-scores in paediatric cardiology. Ann Pediatr Cardiol . 2012;5(2):179-184. doi:10.4103/0974-2069.99622 Pettersen MD, Du W, Skeens ME, Humes RA. Regression equations for calculation of z scores of cardiac structures in a large cohort of healthy infants, children, and adolescents: an echocardiographic study. J Am Soc Echocardiogr . 2008;21(8):922-934. doi:10.1016/j.echo.2008.02.006 Zilberman MV, Khoury PR, Kimball RT. Two-dimensional echocardiographic valve measurements in healthy children: gender-specific differences. Pediatr Cardiol . 2005;26(4):356-360. doi:10.1007/s00246-004-0736-z Cantinotti M, Giordano R, Scalese M, et al. Nomograms for two-dimensional echocardiography derived valvular and arterial dimensions in Caucasian children. J Cardiol . 2017;69(1):208-215. doi:10.1016/j.jjcc.2016.03.010 Sluysmans T, Colan SD. Theoretical and empirical derivation of cardiovascular allometric relationships in children. J Appl Physiol . 2005;99(2):445-457. doi:10.1152/japplphysiol.01144.2004 Colan SD. Normal echocardiographic values for cardiovascular structures. In: Lai WW, Mertens LL, Cohen MS, Geva T, eds. Echocardiography in Pediatric and Congenital Heart Disease: From Fetus to Adult . John Wiley & Sons, Ltd; 2016:883-901. doi:10.1002/9781118742440.app1 Sluysmans T, Colan SD. Structural Measurements and Adjustment for Growth. In: Lai WW, Mertens LL, Cohen MS, Geva T, eds. Echocardiography in Pediatric and Congenital Heart Disease: From Fetus to Adult . 1st ed. Wiley-Blackwell; 2009:53-61. Lopez L, Colan S, Stylianou M, et al. Relationship of echocardiographic Z scores adjusted for body surface area to age, sex, race, and ethnicity: the pediatric heart network normal echocardiogram database. Circ Cardiovasc Imaging . 2017;10(11). doi:10.1161/CIRCIMAGING.117.006979 Colan SD. The why and how of Z scores. J Am Soc Echocardiogr . 2013;26(1):38-40. doi:10.1016/j.echo.2012.11.005 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4406785","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":302903550,"identity":"cadc27d9-c294-4922-be16-c87827cd6245","order_by":0,"name":"Rakesh Donthula","email":"","orcid":"","institution":"the University of Texas McGovern Medical School at Houston","correspondingAuthor":false,"prefix":"","firstName":"Rakesh","middleName":"","lastName":"Donthula","suffix":""},{"id":302903552,"identity":"ec5a45c7-c844-4d78-ad45-0113658e0a84","order_by":1,"name":"Wen Li","email":"","orcid":"","institution":"the University of Texas McGovern Medical School at Houston","correspondingAuthor":false,"prefix":"","firstName":"Wen","middleName":"","lastName":"Li","suffix":""},{"id":302903554,"identity":"71e231cf-3b33-4e60-b6c2-3b2dce576a02","order_by":2,"name":"Archita Duvvada","email":"","orcid":"","institution":"The University of Texas at Austin","correspondingAuthor":false,"prefix":"","firstName":"Archita","middleName":"","lastName":"Duvvada","suffix":""},{"id":302903555,"identity":"fffbf799-6128-4638-ba97-c7cd8bad0493","order_by":3,"name":"Dan Dyer","email":"","orcid":"","institution":"Rady Children’s Hospital","correspondingAuthor":false,"prefix":"","firstName":"Dan","middleName":"","lastName":"Dyer","suffix":""},{"id":302903556,"identity":"04b78b1f-7ff6-4aae-8dc5-f96080946a87","order_by":4,"name":"Santosh C. Uppu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIiWNgGAWjYHADHsYHIJKPWPUSQMXMBiAtbKRoYZMAsQhqMbjde0zyR82dOn7+s8cqv+bYybAxMD98dAOfljvn0qR5jj2TkJyRl3Zbdlsy0GFsxsY5+LTcyDGTZmA7LGFwg8fstuQ2ZqAWHjZpQlokf/wDajl/xqxYcls9cVokeNuAWg7kmDF+3HaYsBbJO+eSrXn7DkvOnJFjLM247TgPGzMBv/Dd7j1488e3w/z8/GcMP/7cVm3Pz9788DE+LQwSPAg2M5jNjE85uhbGH4RUj4JRMApGwYgEANN3Q+LG4bEpAAAAAElFTkSuQmCC","orcid":"","institution":"The University of Texas Health Science Center at Houston","correspondingAuthor":true,"prefix":"","firstName":"Santosh","middleName":"C.","lastName":"Uppu","suffix":""}],"badges":[],"createdAt":"2024-05-11 23:23:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4406785/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4406785/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":56678918,"identity":"8498cbd2-131e-43e2-8420-eb3862734514","added_by":"auto","created_at":"2024-05-17 16:40:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":768623,"visible":true,"origin":"","legend":"\u003cp\u003eExample showing en face measurements of ascending aorta at the level of the pulmonary artery branching using the double oblique method.\u003c/p\u003e","description":"","filename":"Figure1.Ascendingaortameasurements.png","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/155a6dbe6fd47c19493d1814.png"},{"id":56678981,"identity":"a551a701-d93c-4406-b66c-4d616d7ea81c","added_by":"auto","created_at":"2024-05-17 16:40:10","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":450532,"visible":true,"origin":"","legend":"\u003cp\u003eExample showing Aortic root measurements in diastole with the valve closed.\u003c/p\u003e","description":"","filename":"Figure2.Aorticrootdiameterslabeling.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/e49443497a18ca968e2e7cff.jpg"},{"id":56678927,"identity":"ed61030a-d2cc-45c5-bfd2-fbb7403a9862","added_by":"auto","created_at":"2024-05-17 16:40:04","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":741429,"visible":true,"origin":"","legend":"\u003cp\u003eRegression lines for Z-score between − 3.0 and + 3.0 for nonindexed Aortic root diameters in systole and diastole. Sys- systole, Dia- diastole\u003c/p\u003e","description":"","filename":"Figure3.Aorticrootmeasurements.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/d8163fb4e20bb4cfa28fc17b.jpg"},{"id":56678926,"identity":"adb335b4-1d0d-4278-bac5-34df22bc33a6","added_by":"auto","created_at":"2024-05-17 16:40:03","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":143912,"visible":true,"origin":"","legend":"\u003cp\u003eRegression lines for Z-score between − 3.0 and + 3.0 for nonindexed Aortic root mean diameters in systole and diastole. Sys- systole, Dia- diastole\u003c/p\u003e","description":"","filename":"Figure4.Aorticrootmeanmeasurements.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/c94874f560cb9d780ef7e59d.jpg"},{"id":56678923,"identity":"72f86dfd-083b-4016-8d89-3a37bfbbdfe1","added_by":"auto","created_at":"2024-05-17 16:40:03","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1609787,"visible":true,"origin":"","legend":"\u003cp\u003eRegression lines for Z-score between − 3.0 and + 3.0 for nonindexed Aortic maximum diameters in systole and diastole. STJ - sinotubular junction, Sys- systole, Dia- diastole\u003c/p\u003e","description":"","filename":"Figure5.Aorticmaximummeasurements.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/e0c007e249d82f712ddbaeb0.jpg"},{"id":56678986,"identity":"8b553db6-9d6a-47d1-bbd1-0343c67850ed","added_by":"auto","created_at":"2024-05-17 16:40:11","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1599680,"visible":true,"origin":"","legend":"\u003cp\u003eRegression lines for Z-score between − 3.0 and + 3.0 for nonindexed Aortic minimum diameters in systole and diastole. STJ - sinotubular junction, Sys- systole, Dia- diastole\u003c/p\u003e","description":"","filename":"Figure6.Aorticminimummeasurements.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/772d2edf4d3859552e3ff8c4.jpg"},{"id":56678982,"identity":"b9fe132c-7d33-42eb-8494-9522503d4699","added_by":"auto","created_at":"2024-05-17 16:40:10","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":1585588,"visible":true,"origin":"","legend":"\u003cp\u003eRegression lines for Z-score between − 3.0 and + 3.0 for nonindexed Aortic mean diameters in systole and diastole. STJ - sinotubular junction, Sys- systole, Dia- diastole\u003c/p\u003e","description":"","filename":"Figure7.Aorticmeanmeasurements.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/9fa19fa5e33624dbb2c1b1a3.jpg"},{"id":56678937,"identity":"1771a85a-2534-4fcb-b6f1-1c43566e6ad1","added_by":"auto","created_at":"2024-05-17 16:40:04","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":1992135,"visible":true,"origin":"","legend":"\u003cp\u003eRegression lines for Z-score between − 3.0 and + 3.0 for nonindexed Aortic cross-sectional areas in systole and diastole. STJ - sinotubular junction, Sys- systole, Dia- diastole\u003c/p\u003e","description":"","filename":"Figure8.Aorticareameasurements.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/3bed8c36479b4a22319dcdbf.jpg"},{"id":61223223,"identity":"4dbe101a-cb0c-4270-a4cf-cc6ae4325296","added_by":"auto","created_at":"2024-07-27 12:29:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":9848929,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4406785/v1/b3d12561-8fec-47ba-be3a-4fb52e6b95e1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Normative Computed Tomography Angiography Values of the Aortic Root, Aorta and Aortic arch in Children","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOverall survival and outcomes have improved in patients with congenital heart disease due to significant advances in the diagnosis, management, and treatment \u003csup\u003e1 2\u003c/sup\u003e. Cardiac imaging including echocardiography (echo), cardiac ECG-gated computed tomography angiography (CTA), and cardiac Magnetic resonance imaging (CMR) play a vital role in the diagnosis and follow-up of patients with congenital heart defects and patients with connective tissue disease (Marfan, Ehler-Danlos, Loeys-Dietz syndrome etc) \u003csup\u003e3 4 5 6 7\u003c/sup\u003e. Normative data for intracardiac and extracardiac vascular structures in the pediatric population are available for echo, CMR and non ECG-gated CTA \u003csup\u003e8 9 10 11\u003c/sup\u003e. As a result, imagers tend to interpret the CTA aortic measurements with known echo or CMR normative data, this is not ideal due to the inherent variation of the imaging modalities.\u003c/p\u003e \u003cp\u003eThe utility of CTA is gaining acceptance in pediatric cardiology with improvements in scanning techniques, advances in radiation reduction, ease of access, and its ability to limit anesthesia exposure in young children due to fast scan times \u003csup\u003e6,12\u003c/sup\u003e. Cross-sectional imaging with CTA and CMR has added benefit in advanced planning for interventional procedures, creation of virtual or 3D models, overlaying with angiography to reduce radiation dose during an intervention, etc \u003csup\u003e13\u0026ndash;16\u003c/sup\u003e. En face measurements using double oblique technique derived from cross-sectional imaging are made to report major and minor dimensions for a structure which negates the assumption that a vascular structure has a circular profile \u003csup\u003e17\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eSomatic growth should be considered for the pediatric population. For that reason, Z-scores are commonly used with standard deviations (SD) above and below a given measurement, but SDs are not constant across body sizes due to heteroscedasticity adding further complexity to the interpretation. Prior studies have attempted to report non-ECG gated CT diameters of aortic structures \u003csup\u003e18\u0026ndash;20\u003c/sup\u003e. We have previously published normative ECG-gated CT Z-scores for the main and branch pulmonary arteries \u003csup\u003e21\u003c/sup\u003e. In this study, we sought to establish ECG-gated CTA-derived normative values and Z-scores for the aortic root and aorta in children.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eData Sources:\u003c/h2\u003e\n \u003cp\u003eThe study was approved by our institutional review board (The University of Texas Health Science Center at Houston and Memorial Hermann, (HSC-MS-20-1338, September 13\u003csup\u003eth,\u003c/sup\u003e 2021) and waived the need for informed consent. We conducted a retrospective chart review including all consecutive patients less than 18 years of age who underwent ECG-gated- cardiac CTA between January 2015 and December 2020. We identified subjects using our imaging database and electronic medical records. Inpatient and outpatient records were analyzed to obtain baseline information.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003ePopulation:\u003c/h2\u003e\n \u003cp\u003eAll children less than or equal to 18 years of age, who underwent ECG-gated cardiac CTA at our institution from January 2015 to December 2020 who met the inclusion criteria as listed in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e were identified, those meeting the exclusion criteria were removed from the final analysis. The diagnosis and indication of the CTA for the included subjects are listed in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. As cardiac CTA is not routinely performed in normal subjects, we broadly defined subjects without cardiac involvement as \u0026ldquo;normal\u0026rdquo;. Children with vascular rings (double aortic and right aortic arches) were also included in this study. For vascular ring subjects only the aortic root, ascending aorta and descending abdominal aortic measurements away from the vascular ring were recorded as normal, in this way we avoided the area of pathology. As such the number of subjects has been lower compared to an echo or CMR study with similar goals \u003csup\u003e22,23\u003c/sup\u003e.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eInclusion and exclusion criteria\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"3\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eInclusion Criteria\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eExclusion Criteria\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e● Age\u0026thinsp;\u0026le;\u0026thinsp;18 years of age\u003c/p\u003e\n \u003cp\u003e● Structurally normal heart\u003c/p\u003e\n \u003cp\u003e● Vascular ring\u003c/p\u003e\n \u003cp\u003e● Anomalous aortic origin of the coronary artery\u003c/p\u003e\n \u003cp\u003e● Small patent ductus arteriosus in age\u0026thinsp;\u0026lt;\u0026thinsp;1-month\u003c/p\u003e\n \u003cp\u003e● Small patent foramen ovale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e● Any CHD other than listed in the inclusion criteria.\u003c/p\u003e\n \u003cp\u003e● Aortic valve disease\u003c/p\u003e\n \u003cp\u003e● Diagnosed connective tissue disorder (Marfan, Ehler-Danlos, etc.)\u003c/p\u003e\n \u003cp\u003e● Rheumatic heart disease\u003c/p\u003e\n \u003cp\u003e● Depressed ventricular function by echocardiogram\u003c/p\u003e\n \u003cp\u003e● Dilated cardiac chambers by echocardiogram\u003c/p\u003e\n \u003cp\u003e● Motor vehicle accident with cardiac involvement\u003c/p\u003e\n \u003cp\u003e● Motion artifact on the CT scan\u003c/p\u003e\n \u003cp\u003e● History of cardiac surgery/intervention\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\"\u003eCHD- Congenital Heart Defect\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv align=\"left\" class=\"colspec\"\u003e\u003cbr\u003e\u003c/div\u003e\u0026nbsp;\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDiagnosis of included subjects.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"2\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDiagnosis\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNumber (Total N\u0026thinsp;=\u0026thinsp;100)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStructurally normal heart\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAnomalous Aortic origin of coronary arteries\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRCA (\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e), LCA (\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDouble aortic arch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight aortic arch with aberrant left subclavian artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKawasaki disease follow-up with no coronary involvement, normal function\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOthers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\"\u003e\u003cem\u003e*\u003c/em\u003e RCA- Anomalous aortic origin of the right coronary artery, LCA- Anomalous aortic origin of the left coronary artery.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003ePatient selection, preparation, and contrast medium:\u003c/h2\u003e\n \u003cp\u003eAll patients were referred to our imaging center by a pediatric cardiologist for further evaluation. An initial screen was performed by an attending imaging cardiologist prior to cardiac CTA after reviewing echocardiographic information, patient medical records, and available clinical and diagnostic information. Those deemed candidates for CTA followed our institutional imaging protocol. Subjects younger than 6 weeks often underwent feed and swaddle techniques to minimize the need for sedation. Subjects between 6 weeks and 6 years were individualized based on the imaging goal, if anesthesia was needed, deep sedation without intubation was preferred for subjects with vascular rings. In subjects with a feed and swaddle approach image acquisition and timing were geared toward the clinical question. Some of these subjects had diagnostic studies but the image quality may not have been adequate for our study purpose as such they were excluded. Subjects less than 6 years requiring coronary artery evaluation were often anesthetized and intubated for better heart rate and respiratory control to avoid motion artifacts \u003csup\u003e24\u003c/sup\u003e. The location of the peripheral intravenous (PIV) access was determined by the imaging question. To evaluate for the aortic arch abnormalities, a foot PIV was preferred for contrast injection. Iso-osmolar, nonionic, and water‐soluble agents (Iodixanol, Visipaque\u0026trade; 320 mg iodine/ml) were used for all the examinations \u003csup\u003e25\u003c/sup\u003e. The total contrast dose was 1.5\u0026ndash;2 ml/kg of body weight. The contrast medium was administered using a dual‐head power injector at an injection rate of 0.8\u0026ndash;1.2 ml/s for a 24G PIV. The injection rate is increased based on the size of the PIV up to 4-6.5 ml/s \u003csup\u003e12,26\u003c/sup\u003e. A bolus of isotonic saline solution was administered after contrast to reduce high-density contrast (streak) artifact. Automated bolus tracking technique was used with reference cardiovascular structure being monitored at near real-time until predetermined threshold opacification of 120\u0026ndash;150 Hounsfield units was achieved at reference level. A scan delay of 4\u0026ndash;5 seconds was often used for image acquisition \u003csup\u003e27\u003c/sup\u003e.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003eCardiac CTA technique:\u003c/h2\u003e\n \u003cp\u003eDuring the study period, different generations of Siemens CT scanners were used to perform these studies. These include SOMATOM AS 128, SOMATOM definition edge, and SOMATOM Force Dual-source CT (Siemens Healthineers). Studies were performed according to our institutional protocol using a tube voltage of 70\u0026ndash;100 kV and tube current auto modulation (CareDose4D, Siemens Healthineers), a slice thickness of 0.6 mm \u003csup\u003e9,26,28\u003c/sup\u003e. Retrospective electrocardiography (ECG)-gated acquisition was performed when ventricular volume/function and coronary artery evaluation were needed. The prospective ECG‐triggered technique was used to delineate vascular anatomy \u003csup\u003e11\u003c/sup\u003e. Images were reconstructed with a slice thickness of 0.6 mm and an increment of 0.4\u0026ndash;0.6 mm \u003csup\u003e29\u003c/sup\u003e .\u003c/p\u003e\n \u003cp\u003eImages acquired when the aortic valve was open were included under systole, usually between 30 and 40% RR interval. and the images acquired during 70\u0026ndash;80% RR interval were included under diastole. Subjects who underwent retrospectively ECG-gated CTA had both systolic and diastolic images. Prospectively ECG-gated CTA images were acquired either in systole or diastole based on the subject\u0026rsquo;s heart rate as per the machine algorithm and imager preference to minimize motion artifact. All studies were performed with an imaging cardiologist present during the scan.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eImage\u003c/strong\u003e \u003cstrong\u003ePost-processing\u003c/strong\u003e:\u003c/p\u003e\n \u003cp\u003eAll measurements were performed on a cardiovascular imaging workstation (Circle CVI42; Circle Cardiovascular Imaging Inc. Alberta, Canada) after studies were anonymized. All images were visualized in axial, sagittal, and coronal planes with a window (600\u0026ndash;900) and a level (250\u0026ndash;350)\u003c/p\u003e\n \u003cp\u003esettings. Double oblique planes using multiplanar reformatting were performed to measure aortic root, sinotubular junction (STJ), ascending aorta (AAO) at the level of the branch pulmonary artery, proximal (PTA) and distal transverse arch (DTA), aortic isthmus (IS), and descending aorta (DAO) at the level of the diaphragm \u003csup\u003e17,18,30\u003c/sup\u003e. As mentioned arch measurements for vascular ring subjects were not performed to avoid errors. Maximum, minimum, and mean diameters and cross-sectional area are measured for all the parameters except for the aortic root. (Fig.\u0026nbsp;1). For the aortic root, three measurements were made at mid- sinus level at their maximum dimensions. Cusps were named by the expected coronary artery origin, and commissures go along with them \u003csup\u003e31\u003c/sup\u003e. Aortic root measurements for this study are named as follows (Fig.\u0026nbsp;2).\u003c/p\u003e\n \u003cp\u003eA- Right cusp to left/non-coronary commissure diameter\u003c/p\u003e\n \u003cp\u003eB- Left cusp to non-coronary/right commissure diameter\u003c/p\u003e\n \u003cp\u003eC- Non-coronary cusp to right/left commissure diameter.\u003c/p\u003e\n \u003cp\u003eThe measurements were categorized as either systole or diastole as described above. Aortic measurements were performed at the following levels: ascending aorta was measured at the level of the right pulmonary artery/ bifurcation of pulmonary arteries \u003csup\u003e18,20\u003c/sup\u003e, proximal transverse arch was measured immediately after the first branch of aorta, distal transverse arch was measured before the left subclavian artery, isthmus was measured after the last aortic branch. Descending Aorta was measured at the level of the diaphragm \u003csup\u003e18\u003c/sup\u003e.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eStatistical analysis:\u003c/h2\u003e\n \u003cp\u003eData was expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD. The measure of the vessel was indexed to the body surface area (BSA) according to the Haycock formula\u003csup\u003e32\u003c/sup\u003e. The allometric exponent for each parameter was derived by applying the ordinary least squares method in which the natural logarithm of the parameter was\u003c/p\u003e\n \u003cp\u003eregressed on the natural logarithm of BSA \u003csup\u003e33,34\u003c/sup\u003e. This method allows for a nonlinear relationship between the parameter and BSA. Specifically, the following steps were used.\u003c/p\u003e\u003cspan\u003e\n \u003cp\u003e1. The equation \u003cem\u003eY\u0026thinsp;=\u0026thinsp;mX\u003c/em\u003e\u003csup\u003eb\u003c/sup\u003e was considered to decide the potentially nonlinear relationship between a parameter and BSA. \u003cem\u003eY\u003c/em\u003e denoted the parameter, \u003cem\u003eX\u003c/em\u003e denoted BSA, and \u003cem\u003eb\u003c/em\u003e was the AE to be estimated.\u003c/p\u003e\n \u003c/span\u003e \u003cspan\u003e\n \u003cp\u003e2. After taking the natural log, a linear regression formula was obtained: \u003cem\u003eln(Y)\u0026thinsp;=\u0026thinsp;ln(m)\u0026thinsp;+\u0026thinsp;bln(X)\u003c/em\u003e, where \u003cem\u003eln(Y)\u003c/em\u003e was the dependent variable and \u003cem\u003eln(X)\u003c/em\u003e was the independent variable.\u003c/p\u003e\n \u003c/span\u003e \u003cspan\u003e\n \u003cp\u003e3. The regression coefficient estimate \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\widehat{b}\\)\u003c/span\u003e\u003c/span\u003e for \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(b\\)\u003c/span\u003e\u003c/span\u003e from the least squares method was the derived AE.\u003c/p\u003e\n \u003c/span\u003e\n \u003cp\u003eWe then indexed the parameter using BSA to the power of the derived AE. We did the following quality check to make sure that the allometric model was adequate and that there was no residual relationship between the indexed parameter and BSA. The indexed parameter was regressed against\u003c/p\u003e\n \u003cp\u003eBSA. The regression line was plotted, and \u003cem\u003eR\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e was calculated. A flat line and a small \u003cem\u003eR\u003c/em\u003e\u003csup\u003e2\u003c/sup\u003e indicate no residual relationship. Pearson correlation coefficient and the corresponding P value were determined. A correlation close to zero and a P-value\u0026thinsp;\u0026ge;\u0026thinsp;0.05 also indicate no residual relationship.\u003c/p\u003e\n \u003cp\u003eWe checked the normality of the indexed parameter using the Shapiro\u0026ndash;Wilk test and reported \u0026micro;\u0026thinsp;\u0026plusmn;\u0026thinsp;\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\sigma\\)\u003c/span\u003e\u003c/span\u003ewhere \u0026micro; and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\sigma\\)\u003c/span\u003e\u003c/span\u003e denoted the mean and SD of the indexed parameter. Last, we plotted non-indexed parameters against BSA with lines representing the mean, \u0026plusmn; 1, \u0026plusmn; 2, and \u0026plusmn;\u0026thinsp;3 SDs of the mean based on the relationship that the non-indexed parameter followed a normal distribution with a mean of \u0026micro;BSA\u003csup\u003eAE\u003c/sup\u003e and SD of BSA\u003csup\u003eAE\u003c/sup\u003e. Interobserver and intraobserver variability were assessed using the intraclass correlation coefficient in a subset of 50 subjects. All analyses were conducted using R version 4.0.5 (March 2021).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003ePatient characteristics:\u003c/h2\u003e \u003cp\u003eOut of 628 patients who underwent CTA at our institution during the study period, 100 children met the inclusion criteria and were analyzed. The mean age and BSA of the subjects were 5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.1 years (range 0\u0026ndash;18 years) and 0.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.68 m\u003csup\u003e2\u003c/sup\u003e (range 0.16\u0026ndash;2.8 m\u003csup\u003e2\u003c/sup\u003e) respectively. Among the subjects, 56% were male (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The majority (71%) of our subjects were young with a BSA\u0026thinsp;\u0026lt;\u0026thinsp;1 m\u003csup\u003e2\u003c/sup\u003e. The most common finding on the CTA was structurally normal heart (n\u0026thinsp;=\u0026thinsp;29), followed by right aortic arch with aberrant left subclavian artery (n\u0026thinsp;=\u0026thinsp;25), and coronary anomaly (n\u0026thinsp;=\u0026thinsp;21) as shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" morerows=\"1\" nameend=\"c3\" namest=\"c2\" rowspan=\"2\"\u003e \u003cp\u003eMale (56%)\u003c/p\u003e \u003cp\u003e71%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBSA\u0026thinsp;\u0026lt;\u0026thinsp;1 m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMedian (range)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.3 yrs (6.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.3 yrs (0\u0026ndash;18)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eWeight\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26.2 Kg (31.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.75 Kg (2.04\u0026ndash;156)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHeight\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e98 cm (47.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e88.5 cm (44\u0026ndash;187)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBSA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.8 m\u003csup\u003e2\u003c/sup\u003e (0.68)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.6 m\u003csup\u003e2\u003c/sup\u003e (0.16\u0026ndash;2.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eBSA - body surface area, SD - standard deviation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eSystolic measurements for aortic root, STJ, AAO and DAO were available in the majority of our subjects (n\u0026thinsp;\u0026gt;\u0026thinsp;77). Systolic IS and DTA measurements were available in 50 subjects. Systolic PTA measurement was available in very few subjects (n\u0026thinsp;=\u0026thinsp;35) due to common origin of the innominate and left carotid artery (n\u0026thinsp;=\u0026thinsp;15). The Diastolic measurements were available in fewer subjects (root\u0026thinsp;=\u0026thinsp;37, STJ\u0026thinsp;=\u0026thinsp;41, AAO\u0026thinsp;=\u0026thinsp;47, PTA\u0026thinsp;=\u0026thinsp;25, DTA\u0026thinsp;=\u0026thinsp;34, IS\u0026thinsp;=\u0026thinsp;34 and DAO\u0026thinsp;=\u0026thinsp;49 respectively) due to the younger age of our study population the CTA imaging protocols are geared towards acquiring the image during the least heart motion to reduce artifacts. As such systolic imaging was common in young children due to fast heart rates.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eNormative values:\u003c/h3\u003e\n\u003cp\u003eThe normalized mean diameters (mm), cross-sectional area (mm\u003csup\u003e2\u003c/sup\u003e), and standard deviation in systole and diastole are shown in Tables\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, \u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. Based on the results in these tables, we can calculate the Z-score of a measurement for a given BSA using the reported AE, mean, and SD of that parameter:\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMaximum, minimum, mean, and area variables with AE, SD in systole.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSystolic parameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003emean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eStandard Deviation\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e18.236\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.079\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17.398\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.118\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17.817\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.069\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e252.409\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e59.336\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17.842\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.649\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.952\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.674\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17.398\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.625\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e239.495\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e45.584\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e19.021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.929\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e20.029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e20.221\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.151\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e19.757\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.847\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12.704\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.501\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12.234\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.497\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12.469\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.48\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e123.719\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e29.275\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.706\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.777\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13.795\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.637\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.251\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.688\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e161.471\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e38.26\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17.233\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.348\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal transverse arch Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.625\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.898\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal transverse arch Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.977\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal transverse arch Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e213.975\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e50.953\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.891\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.874\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.777\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.716\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.334\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.725\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e186.513\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e41.694\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eMax - maximum diameter, Min - minimum diameter, Mean - mean diameter, area - cross-sectional area, N - number of subjects, AE - allometric exponent, SD- standard deviation. Max, Min, and Mean diameters are reported in millimeters, cross-sectional area is reported in square millimeters. STJ - sinotubular junction. Aortic root: A- Right cusp to left/non-coronary commissure, B- Left cusp to non-coronary/right commissure, C- Non-coronary cusp to right/left commissure.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMaximum, minimum, mean, area variables with AE, SD in diastole.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiastolic parameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003emean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eStandard Deviation\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.646\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.945\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.747\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.233\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.816\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e209.257\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e48.028\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.773\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.979\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.696\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.376\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.715\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e212.678\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e45.333\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17.759\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.746\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e19.323\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.857\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e19.416\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.785\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e18.833\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.673\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e11.902\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.358\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e11.463\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.229\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e11.682\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.271\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e108.346\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e23.556\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.595\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12.809\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.636\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.576\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e139.727\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e32.264\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.624\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.967\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.105\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.885\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.982\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e176.293\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e47.642\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.687\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.871\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e13.744\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.761\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.216\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.775\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Area\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e160.828\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e40.149\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eMax- maximum diameter, Min- minimum diameter, Mean - mean diameter, area - cross-sectional area, N- number of subjects, AE - allometric exponent, SD- standard deviation. Max, Min, and Mean diameters are reported in millimeters, cross-sectional area is reported in square millimeters. STJ - sinotubular junction, STJ - sinotubular junction. Aortic root: A- Right cusp to left/non-coronary commissure, B- Left cusp to non-coronary/right commissure, C- Non-coronary cusp to right/left commissure.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003cdiv id=\"Equa\" class=\"Equation\"\u003e \u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$Z-score = \\frac{indexed value\u0026ndash; \\mu }{\\sigma }$$\u003c/div\u003e \u003c/div\u003e,\u003c/p\u003e \u003cp\u003ewhere\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$indexed value = \\frac{measure{d}_{ }value}{BS{A}^{AE}}$$\u003c/div\u003e\u003c/div\u003e,\u003c/p\u003e \u003cp\u003e\u0026micro; denotes the mean of the indexed parameter, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\sigma\\)\u003c/span\u003e\u003c/span\u003e denotes the SD of the indexed parameter as described in the statistical analysis section. For example, if a subject has an Ascending Aorta Maximum in systole measurement of 17.44 mm and a BSA of 0.6 m\u003csup\u003e2\u003c/sup\u003e, we can derive the Z-score by plugging in the numbers (AE\u0026thinsp;=\u0026thinsp;0.49, mean\u0026thinsp;=\u0026thinsp;18.236, SD\u0026thinsp;=\u0026thinsp;2.079) to the above equations. That is, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(indexed value = \\frac{17.44}{{0.6}^{0.49}}=22.40\\)\u003c/span\u003e\u003c/span\u003e, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(Z-score = \\frac{22.40\u0026ndash;18.236 }{2.079}=2.00\\)\u003c/span\u003e\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe Z-score plots for systolic and diastolic aortic root diameters and their means are shown in Figs.\u0026nbsp;3, and 4. The Z-score plots for systolic and diastolic diameters, mean diameters and cross-sectional areas of the aortic structures are shown in Figs.\u0026nbsp;5, 6, 7 and 8 respectively. As expected systolic diameters were 6\u0026ndash;11% larger and systolic cross-sectional areas were 13\u0026ndash;20% larger compared to diastolic measures. Aortic root systolic measures were 5% larger than the diastolic measures.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eReproducibility:\u003c/h2\u003e \u003cp\u003eThere was an excellent inter and intraobserver agreement (\u0026gt;\u0026thinsp;0.92) for both systolic and diastolic measurements (Tables\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, \u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e) indicating excellent reproducibility of our method.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eInter and intraobserver variability for parameters in systole.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSystole variables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eintra-rater\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003einter-rater\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.978\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.947, 0.991)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.95, 0.994)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.989\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.973, 0.995)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.985\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.956, 0.995)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.975, 0.996)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.987\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.964, 0.996)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.989\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.973, 0.996)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.975\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.927, 0.992)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.987\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.967, 0.995)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.991\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.974, 0.997)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.957, 0.993)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.988\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.963, 0.996)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.958, 0.994)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.978\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.936, 0.993)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.982\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.953, 0.994)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.982\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.946, 0.994)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.991\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.977, 0.997)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.971, 0.997)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.994\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.983, 0.998)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.969, 0.997)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.968\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.923, 0.987)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.975\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.93, 0.992)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.925\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.819, 0.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.978\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.938, 0.992)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.925, 0.988)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.981\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.946, 0.994)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.995\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.981, 0.999)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.991\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.945, 0.999)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.989\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.956, 0.997)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.903, 0.998)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.996\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.985, 0.999)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.991\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.948, 0.999)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.599, 0.988)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.895\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.287, 0.993)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal transverse arch Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.92, 0.998)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.843, 0.999)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal transverse arch Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.967\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.819, 0.995)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.956\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.634, 0.997)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.967\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.871, 0.992)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.964\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.803, 0.995)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.934, 0.996)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.904, 0.998)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.978\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.913, 0.995)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.977\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.868, 0.997)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eMax- maximum diameter, Min- minimum diameter, Mean - mean diameter, STJ - sinotubular junction, STJ - sinotubular junction. Aortic root: A- Right cusp to left/non-coronary commissure, B- Left cusp to non-coronary/right commissure, C- Non-coronary cusp to right/left commissure. CI - confidence interval.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eInter and intraobserver variability for parameters in diastole.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiastole variables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eintra-rater\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003einter-rater\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.995\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.983, 0.999)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.952, 0.996)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.955, 0.996)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.987\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.957, 0.997)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAscending Aorta Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.994\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.979, 0.998)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.993\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.975, 0.998)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.925, 0.995)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.969\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.88, 0.993)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.988\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.956, 0.997)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.979\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.918, 0.995)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic STJ Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.988\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.955, 0.997)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.981\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.923, 0.996)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.966\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.838, 0.994)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.688, 0.991)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.968\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.849, 0.994)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.965\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.808, 0.995)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.93, 0.998)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.976\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.863, 0.996)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.904, 0.997)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.971\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.836, 0.996)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.715, 0.975)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.868\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.579, 0.965)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.959\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.862, 0.989)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.948\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.817, 0.987)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDescending Aorta Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.943\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.813, 0.984)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.922\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.734, 0.98)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.903, 0.998)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.981\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.869, 0.998)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.982\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.899, 0.997)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.979\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.851, 0.998)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsthmus Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.983\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.903, 0.998)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.889, 0.998)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.949\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.677, 0.994)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.961\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.666, 0.997)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.982\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.877, 0.998)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.986\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.87, 0.999)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProximal Transverse arch Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.969\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.792, 0.997)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.981\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.825, 0.999)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Max\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.985\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.913, 0.998)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.975, 1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.994\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.962, 0.999)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.996\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.969, 1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistal Transverse arch Mean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.996\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e(0.975, 0.999)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.997\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e(0.975, 1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eMax- maximum diameter, Min- minimum diameter, Mean - mean diameter, STJ - sinotubular junction, STJ - sinotubular junction. Aortic root: A- Right cusp to left/non-coronary commissure, B- Left cusp to non-coronary/right commissure, C- Non-coronary cusp to right/left commissure. CI - confidence interval.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe report normative systolic, diastolic diameters, cross sectional areas along with Z-scores and normative curves for the aorta, aortic root and aortic arch for ECG-gated cardiac CTA in children younger than 18 years. We report maximum, minimum, and mean diameters as well as the cross-sectional areas for these structures. Normative values in children exist for echo, CMR, and non ECG -gated CTA but are lacking for ECG-gated- CTA \u003csup\u003e35\u0026ndash;37\u003c/sup\u003e. Few non-ECG-gated CTA studies reported normative measurements so far. Akay et al.\u003csup\u003e20\u003c/sup\u003e used single axial measurement with respect to patient age, sex and T- vertebral body size. Bayindir et al.\u003csup\u003e19\u003c/sup\u003e used single measurements from standard axial imaging planes as well. These measurements did not take the patient size into account; as such, the influence of growth and body size in a patient cannot be assessed. This methodology can also be challenging especially in patients with congenital heart defects, heterotaxy, etc. where a single-plane measurement may not be practical.\u003c/p\u003e \u003cp\u003eHegde et al. \u003csup\u003e18\u003c/sup\u003e reported aortic measurements using the double-oblique method using CTAs performed mostly in oncology, chest pain and trauma patients (42%, 16% and 10% respectively); their measurement technique was similar to our study. However, they have not reported cross sectional areas or used ECG-gated CTAs which the authors have recognized as a limitation. Their data was modeled using a natural log-transformed response variable.\u003c/p\u003e \u003cp\u003eEn face measurements of the aorta provide an accurate assessment of the structure of interest \u003csup\u003e17\u003c/sup\u003e. Cardiac CTA is gaining acceptance in congenital cardiology to better evaluate vascular structures due to the improvements in scanning techniques, radiation reduction, ease of access, fast scan times, and reduced need for anesthesia in young children \u003csup\u003e6,28\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eOur study is also unique in reporting both systolic and diastolic normative aortic values; our study confirms larger systolic parameters compared with diastolic measures as was previously described by an angiographic study \u003csup\u003e38\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe cross-sectional area along with the mean diameter may have real-world applicability as the structure of interest can be assessed in any non-standard plane. This is especially important in patients with congenital heart defects where a vascular structure may not be in a normal orientation.\u003c/p\u003e \u003cp\u003eDeriving normative values and Z-scores can be achieved by various methods and there is significant variation among Z-scores derived from each method \u003csup\u003e39\u0026ndash;42\u003c/sup\u003e. We chose the previously described and validated method of using BSA as an expression of body size and linear regression for the relationship between body growth and cardiovascular dimensions \u003csup\u003e43,44 21,33,45\u0026ndash;47\u003c/sup\u003e. Cardiovascular allometry is defined as the relative growth of cardiac structure in relation to somatic growth. Identifying a correct allometric relationship and model for a structure is important for its interpretation and clinical application \u003csup\u003e34,43\u003c/sup\u003e. Multiple authors have advocated the use of an allometric model to identify a true indexing method of a physiologically dependent variable and this method has been widely used for various echo Z-score calculators that are in current clinical use \u003csup\u003e33\u0026ndash;35,43,44\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eRecruiting normal children for a CTA study is ethically not possible due to radiation exposure, need for sedation/anesthesia, and contrast use. It is not uncommon to identify normal subjects who undergo cross-sectional imaging for various reasons to be included in a study. Prior CMR and CTA studies to derive normative values for the aorta and pulmonary arteries have included children with a history of malignancy \u003csup\u003e22,23\u003c/sup\u003e. We have been diligent to include subjects with normal cardiac anatomy, as a result, this data should be close to what is expected for a normal population. Future studies are needed to validate our results with a larger sample. We plan to make our data publicly available.\u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eLimitations:\u003c/h2\u003e \u003cp\u003eOur single-center, small-sample, retrospective study has inherent limitations due to its design. Generalized applicability across institutions may not be possible, but there is a lack of normative ECG-gated-CTA data available at this time. Our data will help kick-start the process of performing a similar study in a multicenter fashion which can help address issues related to a single-center design. Similar goals have been achieved by the Pediatric Heart Network echocardiogram database that published echocardiographic Z-scores, although normative echo Z-scores have been in existence for a few decades. The statistical methodology may have issues with the model of choice, there has been extensive literature on various Z-score models but we felt that our approach is ideal for this study based on extensive prior experience using allometric models in echocardiographic Z-score studies. Our study population was mostly young with 71% having a BSA of less than 1 m\u003csup\u003e2\u003c/sup\u003e, this resulted in less subjects available for the diastolic measurements as the CTA protocols were geared to acquire during systole. We have not reported aortic annulus, descending thoracic aortic measurements, we feel that the abdominal aortic measurements have more clinical significance. Our study has not explored the influence of sex, or race on the Z-scores due to the small sample size, a multicenter design is likely to address this issue. Our sample has predominantly young children, its applicability to older children and adolescents should be done with caution.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThis is the first pediatric study to report en face normative diameters and cross-sectional areas of the aortic root, ascending aorta and aortic arch in systole and diastole derived using ECG-gated cardiac CTA. This data has potential application for proper diagnosis, risk stratification, surgical planning, and planning catheter-related interventions for children with congenital heart defects and connective tissue disorders. The real-world applicability of this tool needs careful validation.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDr. Wen Li’s effort is supported by UL1TR003167.\u003c/p\u003e\n\u003cp\u003eThe other authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Rakesh Donthula and Santosh Uppu. Statistical analysis was performed by Wen Li. The first draft of the manuscript was written by Rakesh Donthula and Santosh Uppu. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConference Presentation:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe abstract was presented at the American Heart Association conference in Chicago, IL on November 5th, 2022.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical standards:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by The University of Texas Health Science Center at Houston and Memorial Hermann Institutional Review Board (HSC-MS-20-1338, September 13\u003csup\u003eth,\u003c/sup\u003e 2021) and waived the need for informed consent. All human studies at the University of Texas at Houston Health Science Center and Memorial Hermann hospital have to go through rigorous review by the ethics committee and have therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinkiand its later amendments. The subjects were deidentified as per our IRB guidelines. Due to the retrospective nature, this study does not require contacting subjects as such a waiver of consent was requested and was approved by the IRB.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMarelli AJ, Ionescu-Ittu R, Mackie AS, Guo L, Dendukuri N, Kaouache M. Lifetime prevalence of congenital heart disease in the general population from 2000 to 2010. \u003cem\u003eCirculation\u003c/em\u003e. 2014;130(9):749-756. doi:10.1161/CIRCULATIONAHA.113.008396\u003c/li\u003e\n\u003cli\u003eGilboa SM, Devine OJ, Kucik JE, et al. 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Relationship of echocardiographic Z scores adjusted for body surface area to age, sex, race, and ethnicity: the pediatric heart network normal echocardiogram database. \u003cem\u003eCirc Cardiovasc Imaging\u003c/em\u003e. 2017;10(11). doi:10.1161/CIRCIMAGING.117.006979\u003c/li\u003e\n\u003cli\u003eColan SD. The why and how of Z scores. \u003cem\u003eJ Am Soc Echocardiogr\u003c/em\u003e. 2013;26(1):38-40. doi:10.1016/j.echo.2012.11.005\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Computed Tomography Angiography, Z-scores, Normative values, Pediatrics, Aorta, Aortic root","lastPublishedDoi":"10.21203/rs.3.rs-4406785/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4406785/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eNormative values for intracardiac and extracardiac vascular structures help in understanding normal growth and changes over time in children; this normative data are not currently available for ECG-gated Computed Tomography Angiography (CTA). We sought to establish ECG-gated CTA derived normative values for the aortic root, aorta and aortic arch in children.\u003c/p\u003e\u003ch2\u003eMethods and Results\u003c/h2\u003e \u003cp\u003eAortic root, ascending aorta, aortic arch, and descending aorta were measured in systole and diastole in 100 subjects who had ECG-gated CTA at our center between January 2015 through December 2020 and met our inclusion criteria. The allometric exponent (AE) for each parameter was derived, and the parameter/body surface area\u003csup\u003eAE\u003c/sup\u003e (BSA\u003csup\u003eAE\u003c/sup\u003e) was established using the previously described methods. Using this data, normalized mean, cross-sectional area, and standard deviation were calculated. Z-score curves were plotted in relation to the BSA for all measurements.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eOur study reports systolic and diastolic ECG-gated CTA Z-scores along with normative curves in relation to BSA for the aortic root, aorta and aortic arch in children.\u003c/p\u003e","manuscriptTitle":"Normative Computed Tomography Angiography Values of the Aortic Root, Aorta and Aortic arch in Children","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-05-17 16:39:40","doi":"10.21203/rs.3.rs-4406785/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8535a69d-e737-4b86-9af2-385214f874f1","owner":[],"postedDate":"May 17th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-07-31T10:26:17+00:00","versionOfRecord":[],"versionCreatedAt":"2024-05-17 16:39:40","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4406785","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4406785","identity":"rs-4406785","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}