Vessel Wall MRI of Unruptured Intracranial Artery Dissection: Serial Changes and Imaging Strategy

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Kwon, Dong-Wha Kang, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6246062/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract We investigated serial changes in intracranial artery dissection (ICAD) from the baseline to 12 months on vessel wall MRI. This prospective study enrolled 17 participants with clear onset of 20 unruptured ICADs between April 2016 and May 2018, and underwent vessel wall MRI within 1 week, and at 1-, 3-, 6-, and 12-months following symptom onset. Detection rates of imaging features, imaging time showing stable morphology and measurements were assessed, and compared between 1- and 3-month using exact McNemar’s and Wilcoxon signed-rank test. Detection rates of imaging features and quantitative measurements in 17 participants with 20 ICADs did not decrease from baseline to 1 month but decreased after 1-month (1 vs.3-months: dissecting flap [20/20 vs. 10/20, P =0.002; 19/20 vs. 9/20, P =0.002], double lumen [9/20 vs. 1/20, P =0.008; 7/20 vs. 1/20; P =0.031], intramural hematoma [18/20 vs. 9/20, P =0.004; 17/20 vs. 9/20; P =0.008], increased outer diameter [15/20 vs. 7/20, P =0.008; 15/20 vs. 8/20, P =0.016], normalized wall index [mean, 0.7 vs. 0.6, P =0.008; 0.8 vs. 0.6, P <0.001], quantitative susceptibility mapping [mean, 0.5 vs. 0.3, P =0.004; 0.4 vs. 0.2 ppm, P =0.031], relative T1-weighted signal intensity [mean, 2.5 vs. 1.5, <0.001; 2.8 vs. 2.0, P =0.007]). However, the decrease and stabilization did not occur in the progressive ICAD (n=2). Stable morphology most frequently appeared at 3 months (8–9/18). Most of dissecting imaging features in ICAD were preserved within 1 month and resolved after 1 month following symptom onset, whereas progressive ICAD may not. Vessel wall MRI in ICAD is suggested to be performed within 1 month. If the dissecting imaging features persist or worsen after 3 months, further progression may be considered. ClinicalTrials.gov, NCT03213470 Health sciences/Diseases/Neurological disorders Health sciences/Diseases/Neurological disorders/Neurovascular disorders Health sciences/Medical research/Study design Health sciences/Medical research/Study design/Clinical trials Health sciences/Health care/Medical imaging/Magnetic resonance imaging Health sciences/Neurology/Neurological disorders/Cerebrovascular disorders Dissection Magnetic resonance imaging Intracranial Arterial Diseases Vessel Wall MRI Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Intracranial artery dissection (ICAD) is an important cause of stroke in young and middle-age patients and is more prevalent in the Asian, than in the non-Asian population (67–78% vs. 11–27% of all cervicocephalic artery dissections) 1 , 2 . Without pathognomonic imaging features such as dissecting flap and double lumen, ICAD is often misdiagnosed as atherosclerosis 3 . Vessel wall MRI has shown improved diagnosis and discriminating unruptured ICAD from atherosclerosis when pathognomonic imaging features are depicted on vessel wall MRI 4 , 5 . The pathology of ICAD evolves faster than that of other intracranial pathologies such as atherosclerosis, moyamoya disease, and vasculitis, which is an important consideration when interpreting imaging findings 2 , 6 . Various imaging features are exhibited in ICAD from diagnosis to chronic disease, with reports of major subsequent geometric change within 2 months 7 or subsequent normalization on luminography within 2 weeks , 8 , 9 . These variable features after the acute stage can cause confusion and prevent precise diagnosis. Additionally, data are lacking on these subsequent geometric changes observed on vessel wall MRI and the appropriate imaging timelines for determining chronological changes 9 – 14 . Predicting final disease outcomes in ICAD is still challenging despite trials using imaging features 8 , 15 – 21 . Ahn et al. reported that aneurysmal morphology shows lower rates of improvement in follow-up imaging relative to non-aneurysmal morphology 18 , and Nakagawa et al. emphasized the importance of early follow-up imaging (within 3 weeks of symptom onset) to predict outcomes and confirm geometric formation 22 . However, they investigated patients with irregular follow-up and insufficient data within the acute and subacute stage, which has been an obstacle in representing dynamic processes and determining disease outcomes. In the present study we presented serial imaging changes in spontaneous unruptured ICAD observed on vessel wall MRI from the baseline to 12 months (≤ 1 week, 1, 3, 6, 12 months following symptom onset) and suggested imaging strategies for ICAD diagnosis. Results Participant Demographics and Clinical Characteristics Included seventeen participants with 20 ICAD lesions (vertebral artery [11], posterior inferior cerebellar artery [3], posterior cerebral artery [2], anterior cerebral artery [2], basilar artery [1], middle cerebral artery [1]) were analyzed by two independent observations (observation 1 by two neuroradiologists and observation 2 by another third neuroradiologist). One participant did not undergo baseline imaging, and six participants did not undergo 6-month imaging. All clinical symptoms improved with time. The participant demographics were shown in Table 1 . Table 1 Participant characteristics and follow-up Variable, numbers of participants (%) Sex Male 12 (67) Female 5 (33) Age (y) ( means ± SDs) 47.1 (range, 33–65) Stroke risk factor Hypertension 9 (53) Diabetes mellitus 1 (6) Hyperlipidemia 3 (18) Smoking 9 (53) BMI (kg/m 2 ) (means ± SDs) 24.7 (range, 18-33.4) Past medical history Coronary artery disease 0 (0) Stroke 1 (6) Chief complaint at baseline presentation and follow-up Imaging interval (month) baseline to 1 month 3–6 months 12 months Dizziness or vertigo 15 3 0 Headache 12 1 0 Sensory change 8 4 1 Dysarthria 6 2 0 Visual disturbance 5 4 1 Weakness 3 0 0 Ataxia 5 2 0 Medication Imaging interval (month) baseline to 1 month 3–6 months 12 months Aspirin(A) + Clopidogrel(C) + Atorvastatin(S) 23 13 4 A + S 3 5 4 A + C 2 6 3 C + S 1 5 3 A 2 0 0 C 2 2 1 Serial Vessel Wall MRI Features Detection rates of imaging features and quantitative measurements did not decrease from baseline to 1 month but decreased after 1 month. The detection rates of dissecting flap were as follows: observation 1, 20/20 (100.0%, 95% CI 83.2–100.0%) in 1 month vs. 10/20 (50.0%, 95% CI 27.2–72.8%) in 3 months ( P = 0.002); observation 2, 19/20 (95.0%, 95% CI 75.1–99.9%) in 1 month vs. 9/20 (45.0%, 95% CI 23.1–68.5%) in 3 months ( P = 0.002). The detection rates of double lumen were as follows: observation 1, 9/20 (45.0%, 95% CI 23.1–68.5%) in 1 month vs. 1/20 (5.0%, 95% CI 0.1–24.9%) in 3 months ( P = 0.008); observation 2, 7/20 (35.0%, 95% CI 15.4–59.2%) in 1 month vs. 1/20 (5.0%, 95% CI 0.1–24.9%) in 3 months ( P = 0.031). The detection rates of intramural hematoma were as follows: observation 1, 18/20 (90.0%, 95% CI 68.3–98.8%) in 1 month vs. 9/20 (45.0%, 95% CI 27.2–72.8%) in 3 months ( P = 0.004); observation 2, 17/20 (85.0%, 95% CI 62.1–96.8%) in 1 month vs. 9/20 (45.0%, 95% CI 23.1–68.5%) in 3 months ( P = 0.008). The detection rates of increased outer diameter were as follows: observation 1, 15/20 (75.0%, 95% CI 45.7–88.1%) in 1 month vs. 7/20 (35.0%, 95% CI 15.4–59.2%) in 3 months ( P = 0.008); observation 2, 15/20 (75.0%, 95% CI 45.7–88.1%) in 1 month vs. 8/20 (40.0%, 95% CI 19.1–63.9%) in 3 months ( P = 0.016). The detection rates of wall enhancement (greater than grade 2) were as follows: observation 1, 11/20 (55.0%, 95% CI 31.5–76.9%) in 1 month vs. 10/20 (50.0%, 95% CI 27.2–72.8%) in 3 months ( P > 0.999); observation 2, 10/20 (50.0%, 95% CI 27.2–72.8%) in 1 month vs. 10/20 in 3 months ( P > 0.999) ( Table 2 ) . Table 2 Serial Changes in Detection Rates of Dissecting Imaging Features ( O1 = observation 1, O2 = observation) Timelines P value Baseline (n = 19) 1 month (n = 20) 3 months (n = 20) 6 months (n = 14) 12 months (n = 20) Dissecting flap O1 19 (100.0) 20 (100.0) 10 (50.0) 4 (28.6) 4 (20.0) 0 . 002 O2 18 (94.7) 19 (95.0) 9 (45.0) 5 (35.7) 5 (25.0) 0 . 002 Double lumen O1 9 (47.4) 9 (45.0) 1 (5.0) 0 (0.0) 0 (0.0) 0.008 O2 7 (36.8) 7 (35.0) 1 (5.0) 1 (7.1) 1 (5.0) 0.031 Intramural hematoma O1 18 (94.7) 18 (90.0) 9 (45.0) 2 (14.3) 3 (15.0) 0.004 O2 16 (84.2) 17 (85.0) 9 (45.0) 2 (14.3) 3 (15.0) 0.008 Increased outer diameter O1 15 (78.9) 15 (75.0) 7 (35.0) 4 (28.6) 4 (20.0) 0.008 O2 15 (78.9) 15 (75.0) 8 (40.0) 4 (28.6) 4 (20.0) 0.016 Wall enhancement (Grade 2) O1 11 (57.9) 11 (55.0) 10 (50.0) 8 (57.1) 7 (35.0) > 0.999 O2 12 (63.2) 10 (50.0) 10 (50.0) 9 (64.3) 9 (45.0) > 0.999 The means of remodeling index were as follows: observation 1, 3.1 (95% CI 2.2–4.1) in 1 month vs. 2.6 (95% CI 1.3–4.0) in 3 months ( P = 0.091); observation 2, 3.1 (95% CI 2.1–4.1) in 1 month vs. 2.6 (95% CI 1.2–4.1) in 3 months ( P = 0.080). The means of normalized wall index were as follows: observation 1, 0.7 (95% CI 0.6–0.8) in 1 month vs. 0.6 (95% CI 0.5–0.7) in 3 months ( P = 0.008); observation 2, 0.8 (95% CI 0.7–0.8) in 1 month vs. 0.6 (95% CI 0.6–0.7) in 3 months ( P < 0.001). The means of QSM were as follows: observation 1, 0.5 ppm (95% CI 0.4–0.5 ppm) in 1 month vs. 0.3 ppm (95% CI 0.2–0.3 ppm) in 3 months ( P = 0.004); observation 2, 0.4 ppm (95% CI 0.3–0.5 ppm) in 1 month vs. 0.2 ppm (95% CI 0.1–0.3 ppm) in 3 months ( P = 0.031). The means of relative T1 signal intensity were as follows: observation 1, 2.5 (95% CI 2.2–2.9) in 1 month vs. 1.5 (95% CI 1.3–1.8) in 3 months ( P < 0.001); observation 2, 2.8 (95% CI 2.4–3.3) in 1 month vs. 2.0 (95% CI 1.5–2.6) in 3 months ( P = 0.007) ( Table 3 ) . Table 3 Serial Changes in Quantitative Values of Geometric Measurements and Intramural Hematoma ( A.U.=arbitrary units, QSM = quantitative susceptibility mapping, ppm = parts per million, O1 = observation 1, O2 = observation) Timelines P value Baseline (n = 19) 1 month (n = 20) 3 months (n = 20) 6 months (n = 14) 12 months (n = 20) Remodeling index (A.U.) O1 3.7 ± 2.2 3.1 ± 2.2 2.6 ± 3.0 2.7 ± 4.4 2.3 ± 4.2 0.091 O2 3.4 ± 1.7 3.1 ± 2.2 2.6 ± 3.1 2.8 ± 4.1 2.4 ± 3.9 0.080 Normalized wall index (A.U.) O1 0.7 ± 0.2 0.7 ± 0.2 0.6 ± 0.2 0.6 ± 0.3 0.5 ± 0.3 0.008 O2 0.7 ± 0.1 0.8 ± 0.1 0.6 ± 0.2 0.6 ± 0.2 0.5 ± 0.3 0.000 Intramural hematoma: QSM (ppm) O1 0.4 ± 0.1 0.5 ± 0.2 0.3 ± 0.1 0.3 ± 0.1 0.2 ± 0.2 0.004 O2 0.4 ± 0.2 0.4 ± 0.2 0.2 ± 0.2 0.2 ± 0.2 0.2 ± 0.2 0.031 Intramural hematoma: T1 (A.U.) O1 2.0 ± 0.8 2.5 ± 0.7 1.5 ± 0.5 1.2 ± 0.4 1.1 ± 0.9 0.000 O2 2.4 ± 1.3 2.8 ± 1.1 2.0 ± 1.1 1.7 ± 0.8 1.6 ± 0.9 0.007 However, two progressive ICAD cases showed persistent dissecting imaging features and progressive aneurysmal dilatation and intramural hematoma on the follow-up imaging (Supplemental table 2 and 3). From baseline to 1 month, there were no significant differences in the detection rates and quantitative measurements of dissecting imaging features ( P > 0.05 ) . Various Vessel Wall MRI Morphologies at 12 months The following imaging features were observed on vessel wall MRI and TOF-MRA at 12 months: complete normalization (n = 2) (Supplemental Fig. 1) , complete normalization with residual wall lesion (n = 3) ( Fig. 2 ) , incomplete normalization (n = 7) ( Fig. 3 ) , aneurysmal dilatation (n = 4) ( Figs. 4 and 5 ) , and occlusion (n = 4). Stable Morphology Stable morphology most frequently appeared at 3 months (observation 1 = 9, observation 2 = 8) followed by that at 6 months (observation 1 = 6, observation 2 = 7) and 1 month (observation 1 = 1, observation 2 = 1). Despite a resolving course, two lesions wherein the 6-month follow-up imaging investigation was not performed were excluded from the analysis of stable morphology. Interobserver agreements Interobserver agreements between two independent obervations in the assessments of imaging features are kappa values of 0.72–0.85 and in the quantitative measurements, showed ICC of 0.71–0.97. Discussion This study was designed to present serial changes in ICAD from the baseline to 12 months on vessel wall MRI and suggest imaging strategies, given the variable and dynamic imaging features of ICAD. Most of dissecting imaging features were preserved between baseline and 1 month and then less detected at 3 months than at 1 month in ICAD. Stable morphology most frequently appeared at 3 months (8–9/18). However, two progressive ICAD did not show the stability. Therefore, the most appropriate imaging time to observe the pathognomonic dissecting imaging features completely using vessel wall MRI appears to be within 1 month. If the dissecting imaging features persist or worsen after 3 months, further progression may be considered. Despite efforts to investigate serial change in spontaneous unruptured ICAD, 2 , 7 , 9 , 18 , 19 , 22 – 25 , to our knowledge, no prospective studies with the same follow-up intervals using vessel wall MRI has been conducted. Thus, irregular follow-up with insufficient data within the acute to subacute stage may constitute an obstacle in representing dynamic processes and investigating outcomes. Prediction of the final imaging morphology using baseline imaging features has been previously attempted 16 , 18 , 19 , 21 , although, given the dynamic processes in arterial dissection, follow-up imaging has been reported as being essential for confirming or predicting the final morphological outcomes 15 , 17 , 20 , 26 , 27 . Mizutani et al presented that major geometric change in most cases occurred within 2 months 7 , and Nakagawa et al postulated that early follow-up imaging (within 3 weeks after symptom onset) is necessary to predict outcomes and confirm the geometric formation 22 . Therefore, changes between the baseline and follow-up imaging features may be important for the evaluation of stable morphology as well as each imaging feature at each imaging time point, and a standardized imaging strategy is necessary to clearly observe the changes. Previous studies reported that aneurysmal morphology in the acute stage is an important prognostic factor for final morphology 18 . Therefore, close monitoring is necessary to detect further enlargement 20 , 27 , multilayered thrombus walls 8 , and enhancement 21 . Two progressive cases in our study also showed persistent thrombosed false lumen with multilayered hematoma, strong wall enhancement, remodeling index, and normalized wall index from the baseline. Therefore, aneurysmal dilatation may be monitored from the acute stage by checking the large positive remodeling index with further enlargement, thrombosed false lumen with multilayered hematoma, and strong wall enhancement. The various and dynamic ICAD imaging features can be a useful guide to interpreting vessel wall MRI. ICAD in the subacute to chronic stages may be challenging to diagnose on other imaging modalities as well as on vessel wall MRI, which presents as gray imaging features between ICAD and other diseases. Complete normalization with residual wall lesions may thus be confused with atherosclerotic lesions without sufficient data. Angiographic findings of deformities with wall lesions in the incomplete normalization and occlusion with decreased outer diameter may be important considerations, especially as they could originate from ICAD occurring in isolated and common locations for dissections. Our study had several limitations. First, our sample size was small as the study was performed in a single tertiary center; therefore, the statistical analyses lack power, and imaging strategies may have been insufficiently proved. Therefore, the statistical significance of our results and of the conclusions requires further validation in future studies and for now remain suggestive. In particular, progressive ICAD was only 2 cases. However, data on serial vessel wall MRI features of ICAD, including imaging in the acute to subacute stages, within the imaging timelines used in our study have been lacking and may be sparse particularly in the early stages. Hence, our results may provide the pilot data for further study. Second, the final follow-up intervals were limited to 12 months, so the clinical and radiological imaging findings at this time point may not represent final features including long-term stability. Third, although we endeavored to retain a standardized imaging timeline, data were missing at seven time points. Fourth, the diagnosis of ICAD based on clinical, laboratory, and imaging characteristics may appear weak without histopathological evidence. Fifth, patients who underwent endovascular treatments were excluded if the procedures were performed in the early phase without short-term follow-up imaging, such as 1- or 3-month post-procedure scans. The baseline images did not reveal any differences in clinical or radiological features compared to the included patients. However, this exclusion may still represent a limitation in the study design. In conclusion, most of dissecting imaging features in ICAD were preserved within 1 month and then resolved after 1 month following symptom onset, whereas progressive ICAD may not. Vessel wall MRI in ICAD is suggested to be performed within 1 month to observe the pathognomonic imaging features completely. If the dissecting imaging features persist or worsen after 3 months, further progression may be considered.\ Materials and Methods Study Participants The protocol of this prospective study (ClinicalTrials.gov, NCT03213470) was approved by the Ethics Committees of the Institutional Review Boards of Asan medical center (Institutional Review Boards number: 2016-0058). All methods were performed in accordance with the relevant guidelines and regulations. Written informed consent was obtained from all participants before enrollment. Between April 2016 and May 2018, 36 participants were enrolled and the first registration was done on 18 April 2016. The inclusion criteria were: (a) age ≥ 18 years, (b) ICAD diagnosis based on clinical history and computed tomography angiography (CTA), magnetic resonance angiography (MRA), and/or digital subtraction angiography (DSA), (c) ICAD which was unruptured, not traumatic, not iatrogenic, and (d) diagnosis within 1 week from a clear symptom onset time. The exclusion criteria were: (a) refusal to participate in the study, (b) endovascular or surgical treatments for target vessels. The participants underwent vessel wall MRI within 1 week and at 1, 3, 6, and 12 months after symptom onset. Demographic information was collected from the clinical records and interviews ( Table 1 ) . Fourteen participants who refused to participate and 5 participants who underwent endovascular treatment were excluded. Seventeen participants with 20 ICAD lesions were finally included in this study, and received 78 vessel wall MRI scans ( Fig. 1 ). Imaging Protocol Vessel wall MRI was performed with a 3.0-T MRI system (Magnetom Skyra; Siemens) with 64-channel head and neck coils, using sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) and 3D turbo spin-echo sequences 28 . T2-weighted images, pre-contrast T1-weighted images (T1WI), and post-contrast T1-weighted images (CE-T1WI) were obtained using SPACE. CE-T1WIs were obtained immediately after intravenous administration of gadoterate meglumine (Dotarem) at 0.1 mmol per kilogram of body weight. The magnitude and phase images of multi-echo (seven echoes) susceptibility-weighted imaging (SWI) was obtained for quantitative susceptibility mapping (QSM) reconstruction. QSM images were reconstructed using STI Suite v3 ( https://people.eecs.berkeley.edu/~chunlei.liu/software.html ) in MATLAB R2016a (The Mathworks) 29 . The imaging parameters were shown in Supplemental table 1 . Image Analysis Two neuroradiologists (S.Y.J. with 6 years’ experience and S.C.J. with 14 years’ experience) analyzed the vessel wall MRIs with consensus readings (observation 1) and another neuroradiologist (Y.H.R. with 5 years’ experience) analyzed the imaging features (observation 2) independently. Image analysis was performed blinded to clinical and laboratory information on a picture archiving and communication system workstation (PetaVision®) using in-house analysis software based on Image J ( http://rsbweb.nih.gov/ii/ ). Vessel wall MRI features were rated on the following 5 features; 1) dissecting flap, 2) double lumen, 3) increased outer diameter (relative to the adjacent normal-appearing arteries), 4) intramural hematoma, and 5) vessel wall enhancement. The remodeling index, normalized wall index, and intramural hematoma on T1WI and QSM were measured. The remodeling index were calculated as the maximal outer wall area in the lesion sites/outer wall area in adjacent normal-looking arteries 30 . The normalized wall index was calculated as the wall area/outer wall area in the maximal stenotic sites 31 . The relative T1 signal intensity was calculated as the signal intensity in intramural hematoma/signal intensity in adjacent muscles on T1W 17 . QSM was normalized relative to cerebrospinal fluid in the lateral ventricles 32 . Observers rated the presence or absence of each imaging feature at each imaging time point. The degree of vessel wall enhancement was assessed on CE-T1WI from grade 0 to 2 9,33 (see details in Supplement). The stages of ICAD were classified as follows: acute stage (< 1month); subacute (1–3 month), chronic (3–12 months). All participants were categorized into five groups at 12 months: complete normalization, complete normalization with residual wall lesion, incomplete normalization, aneurysmal dilatation, and occlusion 10 . The ICAD lesions were classified into stable or progressive dissection according to stability on the TOF-MRA and vessel wall MRI. Stable ICAD was defined as unchanged imaging morphology across consecutive time points lasting 12 months, and among time points of 1, 3, and 6 months, the first time point showing stable morphology was recorded. Lack of stable morphology led to the allocation of the lesion to the progressive ICAD (see details in Supplement). Statistical Analysis All statistical analyses were performed using SPSS (version 21.0, IBM SPSS Statistics), MedCalc version 20.014 (MedCalc Software Ltd), and R (version 3.5.3; R Foundation for Statistical Computing). The independent data assessed through two independent observations was analyzed for detection rates and geometric measurements of imaging features, and signal intensities of intramural hematoma, which were presented with the mean and 95% confidence interval (CI). Detection rates and quantitative measurements were compared between 1 month and 3 months using exact McNemar’s and Wilcoxon signed–rank. Detection rates of stable morphology were compared among evaluations at 1, 3, and 6 months. Interobserver agreements were performed using interclass correlation coefficient (ICC) and kappa. A two-tailed p-value of < .05 was considered statistically significant. Abbreviations ICAD, intracranial artery dissection; CTA, computed tomography angiography; MRA, magnetic resonance angiography; DSA, digital subtraction angiography; CI, confidence interval; T1WI, T1-weighted images Declarations Acknowledgements None Author contribution All authors reviewed the manuscript. Conceptualization: So Yeong Jeong, Seung Chai Jung Data curation: So Yeong Jeong, Seung Chai Jung, Yun Hwa Roh, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim, Keum Mi Choi Formal analysis: So Yeong Jeong, Seung Chai Jung, Yun Hwa Roh, Keum Mi Choi, Sehee Kim Funding acquisition: Seung Chai Jung Investigation: So Yeong Jeong, Seung Chai Jung Methodology: So Yeong Jeong, Seung Chai Jung, Keum Mi Choi, Sehee Kim Project administration: So Yeong Jeong, Seung Chai Jung, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim Resources: So Yeong Jeong, Seung Chai Jung, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim Software: So Yeong Jeong, Seung Chai Jung, Keum Mi Choi Supervision: So Yeong Jeong, Seung Chai Jung, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim Validation: So Yeong Jeong, Seung Chai Jung, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim Visualization: So Yeong Jeong, Seung Chai Jung, Kim, Keum Mi Choi, Sehee Kim Writing—original draft: So Yeong Jeong, Seung Chai Jung, Eunseon Jeong Writing—review & editing: all authors. Data availability statement The data that support the findings of this study are available from the Ethics Committees of the Institutional Review Boards of Asan medical center but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from corresponding author upon reasonable request and with permission of the Ethics Committees of the Institutional Review Boards of Asan medical center Funding: This study was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (NRF-2019R1A2C1089939 and NRF-2020M3E5D2A01084578), the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare & Family Affairs (HI12C1847), Bracco Imaging Korea Ltd. 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Diagnostics (Basel) 11 . https://doi.org/10.3390/diagnostics11061024 (2021). Lee, S. H., Kim, K. Y. & Jung, J. M. High-resolution magnetic resonance imaging for the follow-up of intracranial arterial dissections. Acta Neurol Belg 121, 1599-1605. https://doi.org/10.1007/s13760-020-01432-0 (2021). Tsuda, Y. et al. Importance of Chronological Changes on High-Resolution Vessel Wall Imaging for Diagnosis of Isolated Anterior Cerebral Artery Dissection. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association 29, 105146. https://doi.org/10.1016/j.jstrokecerebrovasdis.2020.105146 (2020). Saito, A. et al. Diagnostic Value of Contrast-Enhanced Magnetic Resonance Vessel Wall Imaging on the Onset Type of Vertebral Artery Dissection. Cerebrovascular diseases 48, 124-131. https://doi.org/10.1159/000503852 (2019). Hashimoto, Y. et al. Monitoring Intramural Hematoma on Vessel Wall Imaging to Evaluate the Healing of Intracranial Vertebral Artery Dissection. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association 30, 105992. https://doi.org/10.1016/j.jstrokecerebrovasdis.2021.105992 (2021). Ahn, S. S. et al. Spontaneous symptomatic intracranial vertebrobasilar dissection: initial and follow-up imaging findings. Radiology 264, 196-202. https://doi.org/10.1148/radiol.12112331 (2012). Kim, B. M. et al. Outcomes and prognostic factors of intracranial unruptured vertebrobasilar artery dissection. Neurology 76, 1735-1741. https://doi.org/10.1212/WNL.0b013e31821a7d94 (2011). Kai, Y. et al. Strategy for treating unruptured vertebral artery dissecting aneurysms. Neurosurgery 69, 1085-1091; discussion 1091-1082. https://doi.org/10.1227/NEU.0b013e3182262adf (2011). Hashimoto, Y. et al. Magnetic resonance vessel wall imaging predicts morphological deterioration in unruptured intracranial artery dissection. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association 29, 105006. https://doi.org/10.1016/j.jstrokecerebrovasdis.2020.105006 (2020). Nakagawa, K. et al. Long-term follow-up study of unruptured vertebral artery dissection: clinical outcomes and serial angiographic findings. Journal of neurosurgery 93, 19-25. https://doi.org/10.3171/jns.2000.93.1.0019 (2000). Park, K. W. et al. Vertebral artery dissection: natural history, clinical features and therapeutic considerations. J Korean Neurosurg Soc 44, 109-115. https://doi.org/10.3340/jkns.2008.44.3.109 (2008). Hirai, T. et al. Intracranial artery dissections: serial evaluation with MR imaging, MR angiography, and source images of MR angiography. Radiation medicine 21, 86-93. (2003). Arauz, A. et al. Dissection of cervical arteries: Long-term follow-up study of 130 consecutive cases. Cerebrovascular diseases 22, 150-154. https://doi.org/10.1159/000093244 (2006). Schievink, W. I. Spontaneous dissection of the carotid and vertebral arteries. The New England journal of medicine 344, 898-906. https://doi.org/10.1056/NEJM200103223441206 (2001). Nagahata, M., Manabe, H., Hasegawa, S. & Takemura, A. Morphological Change of Unruptured Vertebral Artery Dissection on Serial MR Examinations. Evaluation of the Arterial Outer Contour by Basi-parallel Anatomical Scanning (BPAS)-MRI. Interv Neuroradiol 12, 133-136. http://www.ncbi.nlm.nih.gov/pubmed/20569618 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3387940/pdf/IN-12-s1-133.pdf(2006). Park, J. E. et al. Comparison of 3D magnetic resonance imaging and digital subtraction angiography for intracranial artery stenosis. European Radiology 27, 4737–4746. https://doi.org/10.1007/s00330-017-4860-6 (2017). Li, W., Wu, B. & Liu, C. Quantitative susceptibility mapping of human brain reflects spatial variation in tissue composition. Neuroimage 55, 1645-1656. https://doi.org/10.1016/j.neuroimage.2010.11.088 (2011). Zhu, X. J. et al. Morphologic characteristics of atherosclerotic middle cerebral arteries on 3T high-resolution MRI. AJNR. American journal of neuroradiology 34, 1717-1722. https://doi.org/10.3174/ajnr.A3573 (2013). Qiao, Y. et al. MR Imaging Measures of Intracranial Atherosclerosis in a Population-based Study. Radiology 280, 860-868. https://doi.org/10.1148/radiol.2016151124 (2016). Sun, H. et al. Quantitative Susceptibility Mapping for Following Intracranial Hemorrhage. Radiology 288, 830-839. https://doi.org/10.1148/radiol.2018171918 (2018). Qiao, Y. et al. Intracranial plaque enhancement in patients with cerebrovascular events on high-spatial-resolution MR images. Radiology 271, 534-542. https://doi.org/10.1148/radiol.13122812 (2014). Additional Declarations No competing interests reported. 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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-6246062","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":444673786,"identity":"459bb430-dba8-45bc-ae9d-a8102e1e2483","order_by":0,"name":"So Yeong Jeong","email":"","orcid":"","institution":"Seoul National University Bundang Hospital","correspondingAuthor":false,"prefix":"","firstName":"So","middleName":"Yeong","lastName":"Jeong","suffix":""},{"id":444673787,"identity":"6aab568c-2534-4766-b06b-2575b8bc264d","order_by":1,"name":"Seung Chai Jung","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4UlEQVRIiWNgGAWjYDCCAyDCgIHB/ngziCkhQ7wWhjPHEkBaeIjUAgI3ckAaGQhr4buRe/DTjQI7e8YZOZ9f3aix4GFgP3x0Az4tkjfykqVzDJITm3nebrPOOQZ0GE9a2g18WgyA7gFqOZDAxp67zTiHDahFgseMkBbj30At9jwMOc+Mc/4Rp8UMZAvjDI4c5se5bURokTzzxswa5JcNPMfMmHP7JHjYCPmF73iO8e2cP3b2BuzNjz/nfKuT42c/fAyvFgaBBDiTTQJM4lUOAvwH4EzmDwRVj4JRMApGwYgEAMsISTr7QTxnAAAAAElFTkSuQmCC","orcid":"","institution":"Asan Medical Center","correspondingAuthor":true,"prefix":"","firstName":"Seung","middleName":"Chai","lastName":"Jung","suffix":""},{"id":444673788,"identity":"e5bb3992-f656-4590-95fd-f4ad68b8e8e0","order_by":2,"name":"Yun Hwa Roh","email":"","orcid":"","institution":"Asan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Yun","middleName":"Hwa","lastName":"Roh","suffix":""},{"id":444673789,"identity":"2852ecf0-b7ec-4253-bd75-04f411b88bc9","order_by":3,"name":"Sun U. Kwon","email":"","orcid":"","institution":"Asan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Sun","middleName":"U.","lastName":"Kwon","suffix":""},{"id":444673790,"identity":"f4cc3d46-dabe-4a9d-b664-cda73f921b7b","order_by":4,"name":"Dong-Wha Kang","email":"","orcid":"","institution":"Asan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Dong-Wha","middleName":"","lastName":"Kang","suffix":""},{"id":444673791,"identity":"6a121f08-8b9a-43ba-8532-0bc866e8944c","order_by":5,"name":"Jong S. Kim","email":"","orcid":"","institution":"Gangneung Asan Hospital","correspondingAuthor":false,"prefix":"","firstName":"Jong","middleName":"S.","lastName":"Kim","suffix":""},{"id":444673792,"identity":"5a7d38b3-8210-417d-91e1-882da34e5f9e","order_by":6,"name":"Keum Mi Choi","email":"","orcid":"","institution":"Asan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Keum","middleName":"Mi","lastName":"Choi","suffix":""},{"id":444673793,"identity":"7ad07be6-9836-4953-8dfe-15be30fc67b4","order_by":7,"name":"Sehee Kim","email":"","orcid":"","institution":"Asan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Sehee","middleName":"","lastName":"Kim","suffix":""},{"id":444673794,"identity":"dbe88cf9-4dc9-4f85-a8a1-0bcd34048c10","order_by":8,"name":"Eunseon Jeong","email":"","orcid":"","institution":"Asan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Eunseon","middleName":"","lastName":"Jeong","suffix":""}],"badges":[],"createdAt":"2025-03-17 15:38:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6246062/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6246062/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-05732-4","type":"published","date":"2025-07-01T15:58:36+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":81692913,"identity":"4d4f75ff-b9a4-4d96-a8a7-cb92e7eb01dc","added_by":"auto","created_at":"2025-04-30 11:45:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":82433,"visible":true,"origin":"","legend":"\u003cp\u003eFlow Diagram\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6246062/v1/581f489fab138f8ce2476406.png"},{"id":81692915,"identity":"07cb9a92-c7b3-4e62-aba4-68f132d406ca","added_by":"auto","created_at":"2025-04-30 11:45:00","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":578702,"visible":true,"origin":"","legend":"\u003cp\u003eA 56-year-old man with a headache diagnosed with bilateral vertebral artery (VA) dissection, which was later determined to have the complete normalization with residual wall lesion and stable dissection. The acute stage showed a bright, high T1W signal intensity intramural hematoma (arrow), dissecting flap (arrowheads), and aneurysmal dilatation in the right VA on coronal multi-planar reformation (MPR) and axial T1W. The intramural hematoma decreased but remained in the subacute stage in the right VA on the axial T1W and quantitative susceptibility mapping (QSM) (arrows). Vessel wall MRI at 3 months showed improvement of the wall lesion and decreased QSM susceptibility in the right VA on curved MPR and axial T1W and QSM (arrows). Vessel wall MRI at 6 and 12 months showed complete normalization with residual wall lesion (arrows) in the right VA on curved MPR and axial T1W and contrast-enhanced -T1W. Vessel wall enhancement decreased from the acute to chronic stage in the degree on axial contrast-enhanced -T1W (arrows).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6246062/v1/7214481da4bfe09d596c54be.png"},{"id":81695617,"identity":"bbd2063b-efe3-4294-a51d-74fdbfe553b3","added_by":"auto","created_at":"2025-04-30 12:01:02","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":543528,"visible":true,"origin":"","legend":"\u003cp\u003eA 65-year-old woman with blurred vision and dizziness diagnosed with left posterior cerebral artery dissection, which was later determined to have the incomplete normalization and stable dissection. The acute to subacute stage showed dissecting flap on coronal T1W, T2W, and contrast-enhanced -T1W (small arrows), and intramural hematoma on axial T1W (arrow, iso-to-high signal intensity) and axial quantitative susceptibility mapping (QSM) (arrow, positive susceptibility value). Vessel wall MRI at 3 months showed improvement with remaining focal eccentric wall thickening (small arrows) on coronal T1W, T2W, and contrast-enhanced -T1W and decreased T1W signal intensity on axial T1W and QSM susceptibility on axial QSM. Vessel wall MRI at 12 months showed incomplete normalization (small arrows) on coronal T1W, T2W, and CE-T1W.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6246062/v1/9bdf88978028492be17e0ed9.png"},{"id":81692919,"identity":"e6797251-7f09-4e62-801f-d596135a953c","added_by":"auto","created_at":"2025-04-30 11:45:00","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":626906,"visible":true,"origin":"","legend":"\u003cp\u003eA 46-year-old woman with a headache diagnosed with bilateral vertebral artery (VA) to basilar artery (BA) dissection, which was later determined to have the incomplete normalization and aneurysmal dilatation, and stable dissection. The acute stage showed dissecting flaps (arrows) in the right VA on coronal MPR and axial T1W and intramural hematoma (arrows) in the VA to BA junction on axial T1W and quantitative susceptibility mapping (QSM). The amount and intensity of the intramural hematoma (arrows) in the VA and BA increased in the subacute stage on curved multi-planar reformation (MPR) and axial T1W and QSM. Vessel wall MRI at 3 months showed improvement in the residual wall lesion (arrows) of right VA in axial T1W and in intramural hematoma of VA to BA junction on axial T1W and QSM. Vessel wall MRI at 6 months showed improvement in the remaining focal eccentric wall thickening (arrow) and disappearing intramural hematoma in the right VA and BA on all T1W and CE-T1W. Vessel wall MRI at 12 months showed incomplete normalization and focal dissecting aneurysm in the right VA (arrow) on axial T1W, incomplete normalization in the BA (arrow) on coronal MPR T1W, and occlusion of the left VA distal to the posterior inferior cerebellar artery origin (arrow) on axial T1W. Vessel wall enhancement decreased from the acute to chronic stage in the degree on axial contrast-enhanced-T1W (arrows).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6246062/v1/e20cc3b6f811103f591e3c73.png"},{"id":81695616,"identity":"208b4bfd-fbc4-47fe-95ea-b270a206966d","added_by":"auto","created_at":"2025-04-30 12:01:02","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":579406,"visible":true,"origin":"","legend":"\u003cp\u003eA 49-year-old man with ataxia, vertigo, and sensory change diagnosed with right vertebral artery dissection, which was later determined to have the aneurysmal dilatation and progressive dissection. The acute stage showed dissecting flap (arrow) on axial T1W and intramural hematoma on contrast-enhanced (CE)-T1W (arrow, non-enhancing low-to-iso signal intensity) and axial quantitative susceptibility mapping (QSM) (arrow, positive susceptibility). The dissecting aneurysm was formed with a flow through the aneurysm in the subacute stage and increased with wall hematomas at 3 months. The dissecting aneurysm continuously increased in size with wall hematomas (arrows) until 12 months on coronal multi-planar reformation (MPR) and axial T1W, CE-T1W, and QSM. Vessel wall enhancement persisted from the acute to chronic stage in the degree on axial CE-T1W (arrows).\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6246062/v1/f725d0dc57658138c7ebb1f4.png"},{"id":86179247,"identity":"1e6c719e-c734-46c5-a5e8-7c8091705ffd","added_by":"auto","created_at":"2025-07-07 16:17:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3856052,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6246062/v1/6ec562bf-b742-4661-b79e-16e994b319f4.pdf"},{"id":81694263,"identity":"b6e4f882-b955-4224-995f-555db5990a25","added_by":"auto","created_at":"2025-04-30 11:53:00","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":1227078,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementalfiles.docx","url":"https://assets-eu.researchsquare.com/files/rs-6246062/v1/0fc0fe867cf17cda8e837dc1.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Vessel Wall MRI of Unruptured Intracranial Artery Dissection: Serial Changes and Imaging Strategy","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIntracranial artery dissection (ICAD) is an important cause of stroke in young and middle-age patients and is more prevalent in the Asian, than in the non-Asian population (67\u0026ndash;78% vs. 11\u0026ndash;27% of all cervicocephalic artery dissections) \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. Without pathognomonic imaging features such as dissecting flap and double lumen, ICAD is often misdiagnosed as atherosclerosis \u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Vessel wall MRI has shown improved diagnosis and discriminating unruptured ICAD from atherosclerosis when pathognomonic imaging features are depicted on vessel wall MRI \u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe pathology of ICAD evolves faster than that of other intracranial pathologies such as atherosclerosis, moyamoya disease, and vasculitis, which is an important consideration when interpreting imaging findings \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. Various imaging features are exhibited in ICAD from diagnosis to chronic disease, with reports of major subsequent geometric change within 2 months \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e or subsequent normalization on luminography within 2 weeks\u003csup\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. These variable features after the acute stage can cause confusion and prevent precise diagnosis. Additionally, data are lacking on these subsequent geometric changes observed on vessel wall MRI and the appropriate imaging timelines for determining chronological changes \u003csup\u003e\u003cspan additionalcitationids=\"CR10 CR11 CR12 CR13\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePredicting final disease outcomes in ICAD is still challenging despite trials using imaging features \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan additionalcitationids=\"CR16 CR17 CR18 CR19 CR20\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Ahn et al. reported that aneurysmal morphology shows lower rates of improvement in follow-up imaging relative to non-aneurysmal morphology \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e, and Nakagawa et al. emphasized the importance of early follow-up imaging (within 3 weeks of symptom onset) to predict outcomes and confirm geometric formation \u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. However, they investigated patients with irregular follow-up and insufficient data within the acute and subacute stage, which has been an obstacle in representing dynamic processes and determining disease outcomes.\u003c/p\u003e \u003cp\u003eIn the present study we presented serial imaging changes in spontaneous unruptured ICAD observed on vessel wall MRI from the baseline to 12 months (\u0026le;\u0026thinsp;1 week, 1, 3, 6, 12 months following symptom onset) and suggested imaging strategies for ICAD diagnosis.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eParticipant Demographics and Clinical Characteristics\u003c/h2\u003e \u003cp\u003eIncluded seventeen participants with 20 ICAD lesions (vertebral artery [11], posterior inferior cerebellar artery [3], posterior cerebral artery [2], anterior cerebral artery [2], basilar artery [1], middle cerebral artery [1]) were analyzed by two independent observations (observation 1 by two neuroradiologists and observation 2 by another third neuroradiologist). One participant did not undergo baseline imaging, and six participants did not undergo 6-month imaging. All clinical symptoms improved with time. The participant demographics were shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eParticipant characteristics and follow-up\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable,\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003enumbers of participants (%)\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\u003eSex\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e12 (67)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e5 (33)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAge (y) (\u003c/b\u003emeans\u0026thinsp;\u0026plusmn;\u0026thinsp;SDs)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e47.1 (range, 33\u0026ndash;65)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eStroke risk factor\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypertension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e9 (53)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiabetes mellitus\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e1 (6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHyperlipidemia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e3 (18)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSmoking\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e9 (53)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e) (means\u0026thinsp;\u0026plusmn;\u0026thinsp;SDs)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e24.7 (range, 18-33.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePast medical history\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCoronary artery disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStroke\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e1 (6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eChief complaint at baseline presentation and follow-up\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eImaging interval (month)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ebaseline to 1 month\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u0026ndash;6 months\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12 months\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDizziness or vertigo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeadache\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSensory change\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDysarthria\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVisual disturbance\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeakness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAtaxia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMedication\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eImaging interval (month)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ebaseline to 1 month\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u0026ndash;6 months\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12 months\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAspirin(A)\u0026thinsp;+\u0026thinsp;Clopidogrel(C)\u0026thinsp;+\u0026thinsp;Atorvastatin(S)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eA\u0026thinsp;+\u0026thinsp;S\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eA\u0026thinsp;+\u0026thinsp;C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u0026thinsp;+\u0026thinsp;S\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSerial Vessel Wall MRI Features\u003c/h3\u003e\n\u003cp\u003eDetection rates of imaging features and quantitative measurements did not decrease from baseline to 1 month but decreased after 1 month. The detection rates of dissecting flap were as follows: observation 1, 20/20 (100.0%, 95% CI 83.2\u0026ndash;100.0%) in 1 month vs. 10/20 (50.0%, 95% CI 27.2\u0026ndash;72.8%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002); observation 2, 19/20 (95.0%, 95% CI 75.1\u0026ndash;99.9%) in 1 month vs. 9/20 (45.0%, 95% CI 23.1\u0026ndash;68.5%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002). The detection rates of double lumen were as follows: observation 1, 9/20 (45.0%, 95% CI 23.1\u0026ndash;68.5%) in 1 month vs. 1/20 (5.0%, 95% CI 0.1\u0026ndash;24.9%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008); observation 2, 7/20 (35.0%, 95% CI 15.4\u0026ndash;59.2%) in 1 month vs. 1/20 (5.0%, 95% CI 0.1\u0026ndash;24.9%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.031). The detection rates of intramural hematoma were as follows: observation 1, 18/20 (90.0%, 95% CI 68.3\u0026ndash;98.8%) in 1 month vs. 9/20 (45.0%, 95% CI 27.2\u0026ndash;72.8%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.004); observation 2, 17/20 (85.0%, 95% CI 62.1\u0026ndash;96.8%) in 1 month vs. 9/20 (45.0%, 95% CI 23.1\u0026ndash;68.5%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008). The detection rates of increased outer diameter were as follows: observation 1, 15/20 (75.0%, 95% CI 45.7\u0026ndash;88.1%) in 1 month vs. 7/20 (35.0%, 95% CI 15.4\u0026ndash;59.2%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008); observation 2, 15/20 (75.0%, 95% CI 45.7\u0026ndash;88.1%) in 1 month vs. 8/20 (40.0%, 95% CI 19.1\u0026ndash;63.9%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.016). The detection rates of wall enhancement (greater than grade 2) were as follows: observation 1, 11/20 (55.0%, 95% CI 31.5\u0026ndash;76.9%) in 1 month vs. 10/20 (50.0%, 95% CI 27.2\u0026ndash;72.8%) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.999); observation 2, 10/20 (50.0%, 95% CI 27.2\u0026ndash;72.8%) in 1 month vs. 10/20 in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.999) \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eSerial Changes in Detection Rates of Dissecting Imaging Features (\u003c/b\u003eO1\u0026thinsp;=\u0026thinsp;observation 1, O2\u0026thinsp;=\u0026thinsp;observation)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c7\" namest=\"c3\"\u003e \u003cp\u003eTimelines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBaseline (n\u0026thinsp;=\u0026thinsp;19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 month (n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 months (n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6 months (n\u0026thinsp;=\u0026thinsp;14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e12 months (n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eDissecting flap\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (100.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20 (100.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4 (28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0\u003c/b\u003e.\u003cb\u003e002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (94.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19 (95.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9 (45.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5 (35.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5 (25.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0\u003c/b\u003e.\u003cb\u003e002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eDouble lumen\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (47.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9 (45.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.008\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (36.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (35.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1 (7.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1 (5.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.031\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eIntramural hematoma\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (94.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18 (90.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9 (45.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2 (14.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3 (15.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.004\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (84.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17 (85.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9 (45.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2 (14.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3 (15.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.008\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eIncreased outer diameter\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15 (78.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15 (75.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7 (35.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4 (28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.008\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15 (78.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15 (75.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8 (40.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4 (28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.016\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eWall enhancement (Grade 2)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (57.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11 (55.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8 (57.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7 (35.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;0.999\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (63.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9 (64.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e9 (45.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;0.999\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe means of remodeling index were as follows: observation 1, 3.1 (95% CI 2.2\u0026ndash;4.1) in 1 month vs. 2.6 (95% CI 1.3\u0026ndash;4.0) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.091); observation 2, 3.1 (95% CI 2.1\u0026ndash;4.1) in 1 month vs. 2.6 (95% CI 1.2\u0026ndash;4.1) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.080). The means of normalized wall index were as follows: observation 1, 0.7 (95% CI 0.6\u0026ndash;0.8) in 1 month vs. 0.6 (95% CI 0.5\u0026ndash;0.7) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008); observation 2, 0.8 (95% CI 0.7\u0026ndash;0.8) in 1 month vs. 0.6 (95% CI 0.6\u0026ndash;0.7) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The means of QSM were as follows: observation 1, 0.5 ppm (95% CI 0.4\u0026ndash;0.5 ppm) in 1 month vs. 0.3 ppm (95% CI 0.2\u0026ndash;0.3 ppm) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.004); observation 2, 0.4 ppm (95% CI 0.3\u0026ndash;0.5 ppm) in 1 month vs. 0.2 ppm (95% CI 0.1\u0026ndash;0.3 ppm) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.031). The means of relative T1 signal intensity were as follows: observation 1, 2.5 (95% CI 2.2\u0026ndash;2.9) in 1 month vs. 1.5 (95% CI 1.3\u0026ndash;1.8) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001); observation 2, 2.8 (95% CI 2.4\u0026ndash;3.3) in 1 month vs. 2.0 (95% CI 1.5\u0026ndash;2.6) in 3 months (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007) \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e)\u003c/b\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\u003e\u003cb\u003eSerial Changes in Quantitative Values of Geometric Measurements and Intramural Hematoma (\u003c/b\u003eA.U.=arbitrary units, QSM\u0026thinsp;=\u0026thinsp;quantitative susceptibility mapping, ppm\u0026thinsp;=\u0026thinsp;parts per million, O1\u0026thinsp;=\u0026thinsp;observation 1, O2\u0026thinsp;=\u0026thinsp;observation)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c7\" namest=\"c3\"\u003e \u003cp\u003eTimelines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBaseline (n\u0026thinsp;=\u0026thinsp;19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e1 month (n\u0026thinsp;=\u0026thinsp;20)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e3 months (n\u0026thinsp;=\u0026thinsp;20)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6 months (n\u0026thinsp;=\u0026thinsp;14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e12 months (n\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eRemodeling index (A.U.)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e3.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e2.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.3\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.091\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e3.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e2.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.080\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNormalized wall index (A.U.)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.008\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eIntramural hematoma: QSM (ppm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.004\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.031\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eIntramural hematoma: T1 (A.U.)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e2.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e1.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e2.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e2.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e0.007\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eHowever, two progressive ICAD cases showed persistent dissecting imaging features and progressive aneurysmal dilatation and intramural hematoma on the follow-up imaging \u003cb\u003e(Supplemental table 2 and 3).\u003c/b\u003e\u003c/p\u003e \u003cp\u003eFrom baseline to 1 month, there were no significant differences in the detection rates and quantitative measurements of dissecting imaging features (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05\u003cb\u003e)\u003c/b\u003e.\u003c/p\u003e\n\u003ch3\u003eVarious Vessel Wall MRI Morphologies at 12 months\u003c/h3\u003e\n\u003cp\u003eThe following imaging features were observed on vessel wall MRI and TOF-MRA at 12 months: complete normalization (n\u0026thinsp;=\u0026thinsp;2) \u003cb\u003e(Supplemental Fig.\u0026nbsp;1)\u003c/b\u003e, complete normalization with residual wall lesion (n\u0026thinsp;=\u0026thinsp;3) \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e, incomplete normalization (n\u0026thinsp;=\u0026thinsp;7) \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e, aneurysmal dilatation (n\u0026thinsp;=\u0026thinsp;4) \u003cb\u003e(\u003c/b\u003eFigs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e, and occlusion (n\u0026thinsp;=\u0026thinsp;4).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eStable Morphology\u003c/h3\u003e\n\u003cp\u003eStable morphology most frequently appeared at 3 months (observation 1\u0026thinsp;=\u0026thinsp;9, observation 2\u0026thinsp;=\u0026thinsp;8) followed by that at 6 months (observation 1\u0026thinsp;=\u0026thinsp;6, observation 2\u0026thinsp;=\u0026thinsp;7) and 1 month (observation 1\u0026thinsp;=\u0026thinsp;1, observation 2\u0026thinsp;=\u0026thinsp;1). Despite a resolving course, two lesions wherein the 6-month follow-up imaging investigation was not performed were excluded from the analysis of stable morphology.\u003c/p\u003e\n\u003ch3\u003eInterobserver agreements\u003c/h3\u003e\n\u003cp\u003eInterobserver agreements between two independent obervations in the assessments of imaging features are kappa values of 0.72\u0026ndash;0.85 and in the quantitative measurements, showed ICC of 0.71\u0026ndash;0.97.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study was designed to present serial changes in ICAD from the baseline to 12 months on vessel wall MRI and suggest imaging strategies, given the variable and dynamic imaging features of ICAD. Most of dissecting imaging features were preserved between baseline and 1 month and then less detected at 3 months than at 1 month in ICAD. Stable morphology most frequently appeared at 3 months (8\u0026ndash;9/18). However, two progressive ICAD did not show the stability. Therefore, the most appropriate imaging time to observe the pathognomonic dissecting imaging features completely using vessel wall MRI appears to be within 1 month. If the dissecting imaging features persist or worsen after 3 months, further progression may be considered.\u003c/p\u003e \u003cp\u003eDespite efforts to investigate serial change in spontaneous unruptured ICAD, \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan additionalcitationids=\"CR23 CR24\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e, to our knowledge, no prospective studies with the same follow-up intervals using vessel wall MRI has been conducted. Thus, irregular follow-up with insufficient data within the acute to subacute stage may constitute an obstacle in representing dynamic processes and investigating outcomes. Prediction of the final imaging morphology using baseline imaging features has been previously attempted \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e, although, given the dynamic processes in arterial dissection, follow-up imaging has been reported as being essential for confirming or predicting the final morphological outcomes \u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e,\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e,\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Mizutani et al presented that major geometric change in most cases occurred within 2 months \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e, and Nakagawa et al postulated that early follow-up imaging (within 3 weeks after symptom onset) is necessary to predict outcomes and confirm the geometric formation \u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. Therefore, changes between the baseline and follow-up imaging features may be important for the evaluation of stable morphology as well as each imaging feature at each imaging time point, and a standardized imaging strategy is necessary to clearly observe the changes.\u003c/p\u003e \u003cp\u003ePrevious studies reported that aneurysmal morphology in the acute stage is an important prognostic factor for final morphology \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Therefore, close monitoring is necessary to detect further enlargement \u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e,\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e, multilayered thrombus walls \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e, and enhancement \u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Two progressive cases in our study also showed persistent thrombosed false lumen with multilayered hematoma, strong wall enhancement, remodeling index, and normalized wall index from the baseline. Therefore, aneurysmal dilatation may be monitored from the acute stage by checking the large positive remodeling index with further enlargement, thrombosed false lumen with multilayered hematoma, and strong wall enhancement.\u003c/p\u003e \u003cp\u003eThe various and dynamic ICAD imaging features can be a useful guide to interpreting vessel wall MRI. ICAD in the subacute to chronic stages may be challenging to diagnose on other imaging modalities as well as on vessel wall MRI, which presents as gray imaging features between ICAD and other diseases. Complete normalization with residual wall lesions may thus be confused with atherosclerotic lesions without sufficient data. Angiographic findings of deformities with wall lesions in the incomplete normalization and occlusion with decreased outer diameter may be important considerations, especially as they could originate from ICAD occurring in isolated and common locations for dissections.\u003c/p\u003e \u003cp\u003eOur study had several limitations. First, our sample size was small as the study was performed in a single tertiary center; therefore, the statistical analyses lack power, and imaging strategies may have been insufficiently proved. Therefore, the statistical significance of our results and of the conclusions requires further validation in future studies and for now remain suggestive. In particular, progressive ICAD was only 2 cases. However, data on serial vessel wall MRI features of ICAD, including imaging in the acute to subacute stages, within the imaging timelines used in our study have been lacking and may be sparse particularly in the early stages. Hence, our results may provide the pilot data for further study. Second, the final follow-up intervals were limited to 12 months, so the clinical and radiological imaging findings at this time point may not represent final features including long-term stability. Third, although we endeavored to retain a standardized imaging timeline, data were missing at seven time points. Fourth, the diagnosis of ICAD based on clinical, laboratory, and imaging characteristics may appear weak without histopathological evidence. Fifth, patients who underwent endovascular treatments were excluded if the procedures were performed in the early phase without short-term follow-up imaging, such as 1- or 3-month post-procedure scans. The baseline images did not reveal any differences in clinical or radiological features compared to the included patients. However, this exclusion may still represent a limitation in the study design.\u003c/p\u003e \u003cp\u003eIn conclusion, most of dissecting imaging features in ICAD were preserved within 1 month and then resolved after 1 month following symptom onset, whereas progressive ICAD may not. Vessel wall MRI in ICAD is suggested to be performed within 1 month to observe the pathognomonic imaging features completely. If the dissecting imaging features persist or worsen after 3 months, further progression may be considered.\\\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eStudy Participants\u003c/h2\u003e \u003cp\u003e The protocol of this prospective study (ClinicalTrials.gov, NCT03213470) was approved by the Ethics Committees of the Institutional Review Boards of Asan medical center (Institutional Review Boards number: 2016-0058). All methods were performed in accordance with the relevant guidelines and regulations. Written informed consent was obtained from all participants before enrollment. Between April 2016 and May 2018, 36 participants were enrolled and the first registration was done on 18 April 2016. The inclusion criteria were: (a) age\u0026thinsp;\u0026ge;\u0026thinsp;18 years, (b) ICAD diagnosis based on clinical history and computed tomography angiography (CTA), magnetic resonance angiography (MRA), and/or digital subtraction angiography (DSA), (c) ICAD which was unruptured, not traumatic, not iatrogenic, and (d) diagnosis within 1 week from a clear symptom onset time. The exclusion criteria were: (a) refusal to participate in the study, (b) endovascular or surgical treatments for target vessels. The participants underwent vessel wall MRI within 1 week and at 1, 3, 6, and 12 months after symptom onset. Demographic information was collected from the clinical records and interviews \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eFourteen participants who refused to participate and 5 participants who underwent endovascular treatment were excluded. Seventeen participants with 20 ICAD lesions were finally included in this study, and received 78 vessel wall MRI scans \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eImaging Protocol\u003c/h2\u003e \u003cp\u003eVessel wall MRI was performed with a 3.0-T MRI system (Magnetom Skyra; Siemens) with 64-channel head and neck coils, using sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) and 3D turbo spin-echo sequences \u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. T2-weighted images, pre-contrast T1-weighted images (T1WI), and post-contrast T1-weighted images (CE-T1WI) were obtained using SPACE. CE-T1WIs were obtained immediately after intravenous administration of gadoterate meglumine (Dotarem) at 0.1 mmol per kilogram of body weight. The magnitude and phase images of multi-echo (seven echoes) susceptibility-weighted imaging (SWI) was obtained for quantitative susceptibility mapping (QSM) reconstruction. QSM images were reconstructed using STI Suite v3 (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://people.eecs.berkeley.edu/~chunlei.liu/software.html\u003c/span\u003e\u003cspan address=\"https://people.eecs.berkeley.edu/~chunlei.liu/software.html\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e) in MATLAB R2016a (The Mathworks) \u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. The imaging parameters were shown in \u003cb\u003eSupplemental table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003c/b\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eImage Analysis\u003c/h2\u003e \u003cp\u003eTwo neuroradiologists (S.Y.J. with 6 years\u0026rsquo; experience and S.C.J. with 14 years\u0026rsquo; experience) analyzed the vessel wall MRIs with consensus readings (observation 1) and another neuroradiologist (Y.H.R. with 5 years\u0026rsquo; experience) analyzed the imaging features (observation 2) independently. Image analysis was performed blinded to clinical and laboratory information on a picture archiving and communication system workstation (PetaVision\u0026reg;) using in-house analysis software based on Image J (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://rsbweb.nih.gov/ii/\u003c/span\u003e\u003cspan address=\"http://rsbweb.nih.gov/ii/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eVessel wall MRI features were rated on the following 5 features; 1) dissecting flap, 2) double lumen, 3) increased outer diameter (relative to the adjacent normal-appearing arteries), 4) intramural hematoma, and 5) vessel wall enhancement. The remodeling index, normalized wall index, and intramural hematoma on T1WI and QSM were measured. The remodeling index were calculated as the maximal outer wall area in the lesion sites/outer wall area in adjacent normal-looking arteries \u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. The normalized wall index was calculated as the wall area/outer wall area in the maximal stenotic sites \u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. The relative T1 signal intensity was calculated as the signal intensity in intramural hematoma/signal intensity in adjacent muscles on T1W \u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. QSM was normalized relative to cerebrospinal fluid in the lateral ventricles \u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. Observers rated the presence or absence of each imaging feature at each imaging time point. The degree of vessel wall enhancement was assessed on CE-T1WI from grade 0 to 2 \u003csup\u003e9,33\u003c/sup\u003e (see details in Supplement).\u003c/p\u003e \u003cp\u003eThe stages of ICAD were classified as follows: acute stage (\u0026lt;\u0026thinsp;1month); subacute (1\u0026ndash;3 month), chronic (3\u0026ndash;12 months). All participants were categorized into five groups at 12 months: complete normalization, complete normalization with residual wall lesion, incomplete normalization, aneurysmal dilatation, and occlusion \u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. The ICAD lesions were classified into stable or progressive dissection according to stability on the TOF-MRA and vessel wall MRI. Stable ICAD was defined as unchanged imaging morphology across consecutive time points lasting 12 months, and among time points of 1, 3, and 6 months, the first time point showing stable morphology was recorded. Lack of stable morphology led to the allocation of the lesion to the progressive ICAD (see details in Supplement).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eAll statistical analyses were performed using SPSS (version 21.0, IBM SPSS Statistics), MedCalc version 20.014 (MedCalc Software Ltd), and R (version 3.5.3; R Foundation for Statistical Computing). The independent data assessed through two independent observations was analyzed for detection rates and geometric measurements of imaging features, and signal intensities of intramural hematoma, which were presented with the mean and 95% confidence interval (CI). Detection rates and quantitative measurements were compared between 1 month and 3 months using exact McNemar\u0026rsquo;s and Wilcoxon signed\u0026ndash;rank. Detection rates of stable morphology were compared among evaluations at 1, 3, and 6 months. Interobserver agreements were performed using interclass correlation coefficient (ICC) and kappa. A two-tailed p-value of \u0026lt;\u0026thinsp;.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eICAD, intracranial artery dissection; CTA, computed tomography angiography; MRA, magnetic resonance angiography; DSA, digital subtraction angiography; CI, confidence interval; T1WI, T1-weighted images\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors reviewed the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConceptualization:\u0026nbsp;So Yeong Jeong, Seung Chai Jung\u003c/p\u003e\n\u003cp\u003eData curation:\u0026nbsp;So Yeong Jeong, Seung Chai Jung, Yun Hwa Roh, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim, Keum Mi Choi\u003c/p\u003e\n\u003cp\u003eFormal analysis:\u0026nbsp;So Yeong Jeong, Seung Chai Jung, Yun Hwa Roh, Keum Mi Choi, Sehee Kim\u003c/p\u003e\n\u003cp\u003eFunding acquisition: Seung Chai Jung\u003c/p\u003e\n\u003cp\u003eInvestigation:\u0026nbsp;So Yeong Jeong, Seung Chai Jung\u003c/p\u003e\n\u003cp\u003eMethodology:\u0026nbsp;So Yeong Jeong, Seung Chai Jung, Keum Mi Choi, Sehee Kim\u003c/p\u003e\n\u003cp\u003eProject administration:\u0026nbsp;So Yeong Jeong, Seung Chai Jung, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim\u003c/p\u003e\n\u003cp\u003eResources: So Yeong Jeong, Seung Chai Jung, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim\u003c/p\u003e\n\u003cp\u003eSoftware: So Yeong Jeong, Seung Chai Jung, Keum Mi Choi\u003c/p\u003e\n\u003cp\u003eSupervision: So Yeong Jeong, Seung Chai Jung, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim\u003c/p\u003e\n\u003cp\u003eValidation: So Yeong Jeong, Seung Chai Jung, Sun U. Kwon, Dong-Wha Kang, Jong S. Kim\u003c/p\u003e\n\u003cp\u003eVisualization: So Yeong Jeong, Seung Chai Jung, Kim, Keum Mi Choi, Sehee Kim\u003c/p\u003e\n\u003cp\u003eWriting—original draft: So Yeong Jeong, Seung Chai Jung, Eunseon Jeong\u003c/p\u003e\n\u003cp\u003eWriting—review \u0026amp; editing:\u0026nbsp;all authors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from\u0026nbsp;the Ethics Committees of the Institutional Review Boards of Asan medical center\u0026nbsp;but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from corresponding author upon reasonable request and with permission of\u0026nbsp;the Ethics Committees of the Institutional Review Boards of Asan medical center\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e This study was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (NRF-2019R1A2C1089939 and NRF-2020M3E5D2A01084578), the Korea Healthcare Technology R\u0026amp;D Project, Ministry for Health, Welfare \u0026amp; Family Affairs (HI12C1847), Bracco Imaging Korea Ltd. Seoul, South Korea (2016-0058).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eBang, O. Y., Toyoda, K., Arenillas, J. F., Liu, L. \u0026amp; Kim, J. S. 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This prospective study enrolled 17 participants with clear onset of 20 unruptured ICADs between April 2016 and May 2018, and underwent vessel wall MRI within 1 week, and at 1-, 3-, 6-, and 12-months following symptom onset. Detection rates of imaging features, imaging time showing stable morphology and measurements were assessed, and compared between 1- and 3-month using exact McNemar’s and Wilcoxon signed-rank test.\u003cstrong\u003e \u003c/strong\u003eDetection rates of imaging features and quantitative measurements in 17 participants with 20 ICADs did not decrease from baseline to 1 month but decreased after 1-month (1 vs.3-months: dissecting flap [20/20 vs. 10/20, \u003cem\u003eP\u003c/em\u003e=0.002; 19/20 vs. 9/20, \u003cem\u003eP\u003c/em\u003e=0.002], double lumen [9/20 vs. 1/20, \u003cem\u003eP\u003c/em\u003e=0.008; 7/20 vs. 1/20; \u003cem\u003eP\u003c/em\u003e=0.031], intramural hematoma [18/20 vs. 9/20, \u003cem\u003eP\u003c/em\u003e=0.004; 17/20 vs. 9/20; \u003cem\u003eP\u003c/em\u003e=0.008], increased outer diameter [15/20 vs. 7/20, \u003cem\u003eP\u003c/em\u003e=0.008; 15/20 vs. 8/20, \u003cem\u003eP\u003c/em\u003e=0.016], normalized wall index [mean, 0.7 vs. 0.6, \u003cem\u003eP\u003c/em\u003e=0.008; 0.8 vs. 0.6, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001], quantitative susceptibility mapping [mean, 0.5 vs. 0.3, \u003cem\u003eP\u003c/em\u003e=0.004; 0.4 vs. 0.2 ppm, \u003cem\u003eP\u003c/em\u003e=0.031], relative T1-weighted signal intensity [mean, 2.5 vs. 1.5, \u0026lt;0.001; 2.8 vs. 2.0, \u003cem\u003eP\u003c/em\u003e=0.007]). However, the decrease and stabilization did not occur in the progressive ICAD (n=2). Stable morphology most frequently appeared at 3 months (8–9/18). Most of dissecting imaging features in ICAD were preserved within 1 month and resolved after 1 month following symptom onset, whereas progressive ICAD may not. Vessel wall MRI in ICAD is suggested to be performed within 1 month. If the dissecting imaging features persist or worsen after 3 months, further progression may be considered.\u003c/p\u003e\n\u003cp\u003eClinicalTrials.gov, NCT03213470\u003c/p\u003e","manuscriptTitle":"Vessel Wall MRI of Unruptured Intracranial Artery Dissection: Serial Changes and Imaging Strategy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-30 11:44:55","doi":"10.21203/rs.3.rs-6246062/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-18T04:57:54+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-17T09:40:53+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-09T13:40:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"11696054652780517627689913301500287741","date":"2025-04-08T07:28:41+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"42145859772156610332671153637988810852","date":"2025-03-31T07:49:17+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-03-31T04:42:20+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-03-31T04:37:35+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-03-31T04:17:52+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-28T05:38:14+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-03-17T15:23:52+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ecb7bc98-fe65-4e37-8ebc-37193ad6b314","owner":[],"postedDate":"April 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":47345025,"name":"Health sciences/Diseases/Neurological disorders"},{"id":47345026,"name":"Health sciences/Diseases/Neurological disorders/Neurovascular disorders"},{"id":47345027,"name":"Health sciences/Medical research/Study design"},{"id":47345028,"name":"Health sciences/Medical research/Study design/Clinical trials"},{"id":47345029,"name":"Health sciences/Health care/Medical imaging/Magnetic resonance imaging"},{"id":47345030,"name":"Health sciences/Neurology/Neurological disorders/Cerebrovascular disorders"}],"tags":[],"updatedAt":"2025-07-07T16:07:45+00:00","versionOfRecord":{"articleIdentity":"rs-6246062","link":"https://doi.org/10.1038/s41598-025-05732-4","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-07-01 15:58:36","publishedOnDateReadable":"July 1st, 2025"},"versionCreatedAt":"2025-04-30 11:44:55","video":"","vorDoi":"10.1038/s41598-025-05732-4","vorDoiUrl":"https://doi.org/10.1038/s41598-025-05732-4","workflowStages":[]},"version":"v1","identity":"rs-6246062","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6246062","identity":"rs-6246062","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}