Contrast-enhanced MRI in women with endometrial cancer: dynamic versus single-phase acquisitions

Contrast-enhanced MRI in women with endometrial cancer: dynamic versus single-phase acquisitions | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Help Center Sign In Submit a Preprint Cite Share Download PDF Research article Contrast-enhanced MRI in women with endometrial cancer: dynamic versus single-phase acquisitions Myoung Seok Lee, Min Hoan Moon, Taek Min Kim, Siwon Jang, Sohee Oh, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1718202/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: The 2019 ESUR guidelines for endometrial cancer recommend performing either dynamic contrast-enhanced MRI (CE MRI) or single-phase CE MRI. However, no study has directly compared these options. Therefore, this study compared dynamic versus single-phase CE MRI for the evaluation of myometrial invasion in women with endometrial cancer. Methods: This retrospective, single-institution comparative study was conducted among women with surgically proven endometrial cancer, including 30 consecutive women with single-phase CE MRI and 30 age- and pathologic stage-matched women with dynamic CE MRI. Three readers independently compared dynamic and single-phase CE MRI in terms of the tumor-myometrium signal intensity (SI) difference ratio, depth of myometrial invasion, image quality, and image number. Pathologic findings served as a reference standard for the depth of myometrial invasion. Results. The estimated mean SI difference ratios of dynamic CE MRI and single-phase CE MRI fell within an equivalence margin of 0.05 (90% confidence intervals; -0.0497 to 0.0165, -0.0226 to 0.0403, -0.0429 to 0.0433, respectively, for readers A, B, and C). The area under the receiver operating characteristic curve for the detection of deep myometrial invasion was not significantly different between the acquisitions ( P =0.3315, P =0.3345, and P =0.8593, respectively). Single-phase CE MRI showed significantly better image quality than dynamic CE MRI ( P =0.0143, P =0.0042, and P =0.0066, respectively), while the median number of images for dynamic CE MRI was 2.4 times higher than that for single-phase CE MRI. Conclusions. Single-phase acquisition may be a better option for CE MRI in women with endometrial cancer than dynamic acquisition. Magnetic resonance imaging Contrast media Endometrial neoplasms Uterus Figures Figure 1 Figure 2 Figure 3 Background Endometrial cancer, the most common gynecologic malignancy in developed countries [ 1 ], is surgically staged according to the 2009 Federation of Gynecology and Obstetrics (FIGO) system, which includes evaluations of metastasis to the pelvic and paraaortic lymph nodes [ 2 ]. Lymphadenectomy has been considered part of the surgical staging procedure; however, most surgeons believe that lymphadenectomy is not necessary for women at a low risk of lymph node metastasis, and not performing lymphadenectomy avoids its concomitant risks and complications [ 3 ]. The European Society for Medical Oncology (ESMO) recently recommended that the surgical staging of endometrial cancer should be tailored based on the risk of lymph node metastasis [ 4 ]. According to the ESMO guidelines, lymphadenectomy is not recommended in low-risk patients with grade 1 or 2 endometrioid adenocarcinoma without deep myometrial invasion. Magnetic resonance imaging (MRI) is the most preferred imaging modality used to stratify women with endometrial cancer into low-risk versus intermediate- to high-risk groups because it is the modality that best determines the depth of myometrial invasion [ 5 – 8 , 2 , 9 – 12 ]. T2-weighted imaging (T2WI), contrast-enhanced imaging, and diffusion weighted imaging (DWI) are key MRI sequences to assess myometrial invasion of endometrial cancer. Of these, contrast-enhanced MRI (CE MRI) is mostly performed as high-temporal-resolution, dynamic CE MRI [ 13 , 8 , 14 – 17 ]. However, high-spatial-resolution, single-phase CE MRI is also an option. Our prior experience with dynamic CE MRI suggested that the temporal window for tumor-myometrium contrast in endometrial cancer is not narrow enough to require dynamic CE MRI [ 15 ]. Since radiologists invest substantial time and effort into reviewing hundreds of dynamic CE MRI images, it needs to be clarified whether high temporal resolution is required for CE MRI in women with endometrial cancer. Therefore, our study was conducted to evaluate whether high temporal resolution is required for contrast-enhanced MRI in women with endometrial cancer by comparing dynamic CE MRI with single-phase CE MRI. Methods This retrospective, single-institutional comparative study was approved by our institutional review board, and the requirement for informed consent was waived due to the retrospective nature of the study. Study population Before May 2014, our institution conducted dynamic CE MRI as a standard part of preoperative MRI for endometrial cancer. Based on scientific evidence [ 15 ], we adopted single-phase CE MRI instead of dynamic CE MRI in May 2014. We retrospectively searched our database for women who underwent single-phase CE MRI and surgically proven endometrial cancer, and the last 30 consecutive women were selected as the single-phase CE MRI group. Among women who underwent dynamic CE MRI and had surgically proven endometrial cancer, 30 age- and surgicopathologic stage-matched women were chosen for comparison as the dynamic CE MRI group. A deviation of ± 3 years was allowed for age matching. Image acquisition The MRI studies were performed with a 1.5-T MRI unit (Achieva and Intera; Philips Medical Systems, Best, the Netherlands) using a phased-array torso coil. The patients were asked to fast for 4–6 hours and empty the bladder before MRI to reduce motion artifacts [ 18 ]. In addition, half an hour before MRI, the patients received an intramuscular injection of 20 mg of scopolamine butylbromide (Buscopan; Boehringer Ingelheim Korea, Seoul, Korea) as an antiperistaltic agent. Our MRI protocol for endometrial cancer is summarized in Table 1 . A fat-saturated T1-weighted three-dimensional fast field echo sequence was used for both dynamic CE MRI and single-phase CE MRI. For dynamic CE MRI (Fig. 1 ), oblique axial images were obtained perpendicular to the endometrial cavity, and the scan percentage was reduced to 60% to allow a temporal resolution of 25–40 seconds depending on the uterine size. The loss of image resolution from the reduced scan percentage was compensated with the peripheral part of the k-space of the last dynamic reference scan [ 19 ]. Imaging began simultaneously with the administration of 0.1 mmol gadolinium/kg body weight, injected at a rate of 2 mL/s through an antecubital vein, and approximately 7–12 continuous sets of image series were acquired during 4–6 minutes of examination. For single-phase CE MRI (Fig. 2 ), coronal images were obtained with a slice thickness of 1 mm and a space of 0.5 mm. Because single-phase CE MRI required an average of 4 minutes and 40 seconds, a linear profile order was used to fill the central k-space with an appropriate imaging delay [ 15 ]. The obtained coronal data were immediately reconstructed into sagittal, coronal, and oblique axial planes by the technologists at the console and then transferred to the picture archiving and communication system (PACS: Marosis M-view, Infinitt, Seoul, Korea). A 2-mm thickness and no interslice gap were chosen to facilitate comparison with the standard anatomic sequences. The average time for image reconstruction was approximately 1 minute. Table 1 Imaging parameters of standardized MRI protocols for endometrial cancer. Sequence T2 TSE T1 TSE DWI Dynamic CE MRI Single-phase CE MRI Plane Sagittal Axial Obl 1 axial Axial (Obl 1 ) axial Obl 1 axial Coronal Bandwidth (Hz) 250 250 32 190 189.9 Repetition time (ms) 6000 620 2420 5–6 8.1 Echo time (ms) 100 10 70 2–3 3.7 Flip angle ( o ) 90 90 90 10 12 Sense factor 1 1 2 2/1 2/1 Echo train length 17 3 53 54 26 Slice thickness (mm) 5 5 5 4 1 space (mm) 6 6 6 6 0.5 Number of signal average 2 2 4 2 2 Field of view (cm) 25 25 25 25 25 Matrix 256*256 256*256 100*100 356*356 252*250 Scan time (min:sec) 3:10 3:30 3:00 4:00–6:00 4:40 Note-TSE = turbo spin-echo, DWI = diffusion weighted imaging, CE MRI = contrast-enhanced MRI 1 Obl indicates oblique, and oblique axial images were obtained perpendicular to the endometrial cavity. Image analysis For each woman included in this study, the MR images were loaded to a dedicated study worklist on the PACS after the removal of personal identifying information by an author (***) who did not participate in subsequent image interpretation. Two genitourinary radiologists (*** [reader 1] and *** [reader 2] with 4 years and 15 years of experience in genitourinary imaging, respectively) and one fourth-year resident (*** [reader 3]), who were informed of the primary aim of the study but blinded to the surgicopathologic results of each patient, independently evaluated the dynamic CE MRI and single-phase CE MRI in a random order, with reference to the T2WI and DWI sequences, for the following: (a) the tumor-myometrium signal intensity (SI) difference ratio, (b) the depth of myometrial invasion (superficial vs. deep) [ 20 ], and (c) image quality. Image quality was scored according to a 4-point grading system (Table 2 ), and the SI difference ratio was calculated as follows: SI difference ratio = (SI m – SI c ) /(SI m + SI c ), where SI m is the signal intensity of the myometrium, and SI c is the signal intensity of the endometrial cancer. This formula provides a unitless parameter between 0 and 1, with 1 representing the greatest relative contrast. For dynamic CE MRI, the SI difference ratio was calculated from the images that showed the largest subjective contrast difference between the tumor and the myometrium. Myometrial invasion was scored as superficial if the tumor showed no invasion or invasion of less than half of the myometrium, while deep myometrial invasion was defined as invasion of at least half of the myometrium [ 20 ]. In addition, subendometrial enhancement (SEE) on dynamic CE MRI was assessed by consensus between readers 1 and 2 with the following classification: (a) no demonstrable SEE, (b) disrupted SEE, and (c) intact SEE [ 16 , 21 ]. The number of images was counted by reader 2 for subsequent analysis. Table 2 Grading of diagnostic image quality Score Diagnostic quality Description 4 Excellent Clear depiction of the uterus 3 Adequate Minor artifact that did not interfere with image interpretation 2 Questionable Impaired depiction of the uterus 1 Nondiagnostic Insufficient image quality Histopathologic analysis Most of the study participants (n = 57) underwent standard operations consistent with the current International FIGO surgicopathologic staging and guidelines (pelvic washing for cytologic analysis, total abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymphadenectomy with or without paraaortic lymphadenectomy) [ 20 ]. Lymphadenectomy was omitted in the remaining three women according to the clinicians’ discretion. Surgicopathologic reports were prospectively provided as part of daily practice by one of four staff pathologists who were blinded to the results of the MRI studies, with a prescribed form that included the depth of myometrial invasion. Statistical analysis Statistical analyses were performed with MedCalc (version 18.6, MedCalc Software, Mariakerke, Belgium). To test the equivalence of the tumor-myometrium SI difference ratio between single-phase CE MRI and dynamic CE MRI, two one-sided tests for independent means were used with a margin of 0.05 [ 22 , 23 ], which was inferred from the interquartile range of the SI difference ratio in a previous study [ 15 ]. The diagnostic performance in the assessment of deep myometrial invasion was compared using the area under the receiver operating characteristic curve (AUC). The image quality and the number of images were compared using the Wilcoxon rank-sum test. A P value of less than 0.05 was considered to indicate a statistically significant difference. Interobserver agreement was assessed using the weighted kappa (κ) statistic with the following categories: a κ value of less than 0 indicated poor agreement, a κ value of 0–0.20 indicated slight agreement, a κ value of 0.21–0.40 indicated fair agreement, a κ value of 0.41–0.60 indicated moderate agreement, a κ value of 0.61–0.80 indicated substantial agreement, and a κ value of 0.81-1.0 indicated near perfect agreement. Results In all 60 women (mean age: 56 \(\pm\) 10 years in the dynamic CE MRI group and 57 \(\pm\) 9 years in the single-phase CE MRI group), pathologic confirmation of endometrial cancer was obtained following hysterectomy. The specimens showed no invasion or invasion of less than half of the myometrium in 42 women and invasion of half or more of the myometrium in 18 women. The surgicopathologic characteristics of the study participants are summarized in Table 3 . The median interval between MRI and surgery was 11 days (95% confidence interval [CI]: 7–76 days) in the dynamic CE MRI group and 10 days (95% CI: 7–11 days) in the single-phase CE MRI group. Table 3 Surgicopathologic characteristics of the study participants Variable Dynamic CE MRI Single-phase CE MRI Histologic subtype Endometrioid 24 (80.0) 26 (86.7) Serous papillary 2 (6.7) - Mucinous - - Clear cell - 1 (3.3) Squamous - - Undifferentiated 1 (3.3) - Mixed 3 (1.0) 3 (1.0) Histologic grade Well differentiated 11 (36.7) 16 (53.3) Moderately differentiated 12 (40.0) 10 (33.3) Poorly differentiated 6 (20.0) 2 (6.7) Not determined 1 (3.3) 2 (6.7) Myometrial invasion No or less than half 21 (70.0) 21 (70.0) Equal to or more than half 9 (30.0) 9 (30.0) Surgical stage IA 15 (50.0) 18 (60.0) IB 2 (6.7) 4 (13.3) II 4 (13.3) 4 (13.3) IIIA 4 (13.3) 1 (3.3) IIIB 1 (3.3) - IIIC 4 (13.3) 3 (10.0) IVA - - IVB - - Note: Data represent numbers of women, with percentages in parentheses. SI difference ratio For reader A, the SI difference ratio of dynamic CE MRI ranged from 0.03 to 0.42, with a median value of 0.18, while that of single-phase CE MRI ranged from 0.04 to 0.33, with a median value of 0.20. For reader B, the SI difference ratio of dynamic CE MRI ranged from 0.04 to 0.42, with a median value of 0.22, while that of single-phase CE MRI ranged from 0.06 to 0.36, with a median value of 0.21. For reader C, the SI difference ratio of dynamic CE MRI ranged from 0.06 to 0.45, with a median value of 0.22, while that of single-phase CE MRI ranged from 0.07 to 0.31, with a median value of 0.22. The dynamic and single-phase CE MRI SI difference ratios were found to be equivalent for all readers with a margin of equivalence of 0.05 (90% CI of the mean difference: -0.0497 to 0.0165, -0.0226 to 0.0403, and − 0.0429 to 0.0433, respectively, for readers A, B, and C) (Fig. 3 ). Diagnostic performance The sensitivity and specificity of dynamic and single-phase CE MRI in the detection of deep myometrial invasion are summarized in Table 4 and the AUCs in the detection of deep myometrial invasion are presented in Table 5 . For all readers, the difference in the AUC between dynamic and single-phase CE MRI was not significant ( P = 0.3315, P = 0.3345, and P = 0.8593, respectively, for readers A, B, and C). The interobserver agreement in the diagnosis of deep myometrial invasion was substantial for dynamic CE MRI and moderate to substantial for single-phase CE MRI (Table 6 ). Table 4 Sensitivity and specificity of dynamic CE MRI and single-phase CE MRI in the detection of deep myometrial invasion in women with endometrial cancer. Reader Sensitivity (%) Specificity (%) Dynamic CE MRI Single-phase CE MRI Dynamic CE MRI Single-phase CE MRI Reader A 67 (6/9) 89 (8/9) 86 (18/21) 86 (18/21) Reader B 44 (4/9) 78 (7/9) 95 (20/21) 86 (18/21) Reader C 44 (4/9) 44 (4/9) 86 (18/21) 90 (19/21) Table 5 AUC values for dynamic CE MRI and single-phase CE MRI in the detection of deep myometrial invasion in women with endometrial cancer. Reader Dynamic CE MRI Single-phase CE MRI P value Reader A 0.762 (0.572–0.897) 0.873 (0.701–0.966) 0.3315 Reader B 0.698 (0.504–0.851) 0.817 (0.634–0.934) 0.3345 Reader C 0.651 (0.456–0.815) 0.675 (0.480–0.833) 0.8593 * Data are AUC values, with 95% CIs in parentheses. Note-AUC = area under the curve. Table 6 Interobserver agreement of dynamic CE MRI and single-phase CE MRI in the evaluation of deep myometrial invasion. Dynamic CE MRI Single-phase CE MRI A vs. B 0.64 (0.33–0.95) 0.63 (0.34–0.92) A vs. C 0.66 (0.36–0.96) 0.60 (0.31–0.89) B vs. C 0.79 (0.52-1.00) 0.50 (0.17–0.83) * Data are κ values, with 95% CIs in parentheses. Subendometrial enhancement SEE was depicted in only 30.0% (9/30) of women who underwent dynamic CE MRI, and SEE was demonstrated in 17.7% (1/6) of premenopausal women who were eligible for fertility-sparing management. In all cases, SEE was disrupted and no women showed intact SEE. Image quality For reader A, the image quality of dynamic CE MRI ranged from 1 to 4, with a median score of 3, while that of single-phase CE MRI ranged from 2 to 4, with a median score of 3. For reader B, the image quality of dynamic CE MRI ranged from 1 to 4, with a median score of 3, while that of single-phase CE MRI ranged from 2 to 4, with a median score of 3. For reader C, the image quality of dynamic CE MRI ranged from 1 to 3, with a median score of 3, while that of single-phase CE MRI ranged from 2 to 4, with a median score of 3. For all readers, image quality was significantly better for single-phase CE MRI than for dynamic CE MRI ( P = 0.0143, P = 0.0042, and P = 0.0066, respectively, for readers A, B, and C). Number of images The number of images for dynamic CE MRI ranged from 350 to 880, with a median of 640, while that for single-phase CE MRI ranged from 112 to 300, with a median of 270. The median number of images was 2.4 times higher for dynamic CE MRI than for single-phase CE MRI, and the difference was statistically significant ( P < 0.0001). Discussion Moon et al. reported that an imaging delay of approximately 90 seconds after contrast material injection may be optimal to obtain appropriate tumor-myometrium contrast in women with endometrial cancer. In their study, the appropriate tumor-myometrium contrast tended to continue or increase over time and not be instantaneous [ 15 ]. Therefore, as long as the central k -space data for tumor-myometrium contrast are obtained after an appropriate imaging delay, single-phase CE MRI can be performed without losing tumor-myometrium contrast, compared to dynamic CE MRI. In the present study, the k -space profile order was set to be linear and the central lines were acquired halfway through the acquisition. By doing so, we could fill the central k-space data 2 or 3 minutes after contrast material injection because the acquisition of single-phase CE MRI took approximately 4–6 minutes. As expected, the tumor-myometrium SI difference ratio was not significantly different between dynamic CE MRI and single-phase CE MRI ( P = 0.2342, P = 0.7553, and P = 0.9410, respectively, for readers A, B, and C). The volume data for single-phase CE MRI can be reconstructed into multiple imaging planes. Using several planes was expected to improve the diagnostic performance of CE MRI in the assessment of deep myometrial invasion; however, although the performance of single-phase CE MRI was better than that of dynamic CE MRI for all readers in the present study, statistically significant differences were not demonstrated between dynamic and single-phase CE MRI (Table 5 ). We assume that the use of T2WI and DWI for reference and the small number of patients in the study might have been responsible for this unexpected result, but future studies are needed to clarify our assumptions. The improved temporal resolution of dynamic CE MRI was expected to increase tumor-myometrium contrast, but as shown in the present study, dynamic CE MRI did not show better tumor-myometrium contrast than single-phase CE MRI in women with endometrial cancer. Instead, decreasing signal acquisition for spatial information led to deterioration of the image quality [ 24 ], as was also demonstrated in the present study. Another reason for performing dynamic CE MRI in women with endometrial cancer is the expectation of demonstrating SEE, which is a thin layer of enhancement between the endometrium and the myometrium [ 21 ]. In women with endometrial cancer, myometrial invasion can be ruled out by demonstrating an intact SEE on dynamic CE MRI, which is useful information when fertility-sparing management is under consideration [ 25 , 21 , 16 ]. However, the role of dynamic CE MRI in the selection of fertility-sparing management may be limited, given that SEE cannot be demonstrated on dynamic CE MRI in many women, especially premenopausal women [ 21 , 16 ]. Our study also showed that SEE was not frequently demonstrated on dynamic CE MRI. Furthermore, Nakao et al. reported that eight (40%) of 20 women with intact SEE on dynamic CE MRI were eventually found to have myometrial invasion [ 26 ]. Given these findings, we need to reconsider whether dynamic CE MRI should be used to select women for fertility-sparing management. In the last few decades, the workload in radiology has dramatically increased with the advent of the PACS, increased utilization of advanced cross-sectional imaging with much larger sets of data, and an overall increase in the number of imaging studies [ 27 ]. The increasing workload has resulted in high rates of radiologist burnout, and this trend has only continued to worsen [ 28 , 29 ]. In the present study, dynamic CE MRI produced 2.4 times more images than single-phase CE MRI, meaning that radiologists would need to invest more time and effort in interpreting CE MRI. Since CE MRI does not require high temporal resolution for endometrial cancer, single-phase CE MRI may be a better choice than dynamic CE MRI in the era of radiologist burnout. Our study has several limitations. First, the small number of the study population and retrospective nature of the present study may have introduced bias. Second, although we tried to control for confounding variables by matching age and pathologic staging, this study could not be completely free from selection bias because we were not able to perform both dynamic CE MRI and single-phase CE MRI in the same women. The third limitation is that DWI, which has been increasingly highlighted [ 8 , 10 ], was not compared with CE MRI. We know that readers are curious about the comparison of CE MRI and DWI, but we believe that the question should be addressed after clarifying the preferable acquisition method for CE MRI. Finally, all women enrolled in the present study were scanned only with a 1.5 Tesla MRI unit. Since the magnetic field strength could affect spatial and temporal resolution, additional studies will be needed to elucidate the effects of magnetic field strength on CE MRI. Conclusions In the present study for CE MRI in women with endometrial cancer, single-phase acquisition did not impair the tumor-myometrium contrast that could be obtained by dynamic acquisition. Single-phase acquisition and dynamic acquisition showed similar diagnostic performance in the detection of deep myometrial invasion. In addition, single-phase CE MRI provided better image quality and fewer images than dynamic CE MRI. In the era of radiologist burnout, therefore, we believe that single-phase acquisition might be a better option for CE MRI than dynamic acquisition in women with endometrial cancer. Abbreviations (AUC) area under the receiver operating characteristic curve (CE MRI) contrast-enhanced MRI (CI) confidence interval (DWI) diffusion weighted imaging (ESMO)European Society for Medical Oncology (FIGO) Federation of Gynecology and Obstetrics (MRI) Magnetic resonance imaging (SEE) subendometrial enhancement (SI) signal intensity (T2WI) T2-weighted imaging Declarations Ethics approval and consent to participate This retrospective, single-institutional comparative study was approved by the institutional review board of Boramae Medical Center (03-2017-12), and the requirement for informed consent was waived due to the retrospective nature of the study. Consent for publication Not applicable Availability of data and materials The data that support the findings of this study are available from the corresponding author, but restrictions apply to the availability of these data. Data are available from the authors upon reasonable request and with permission of the corresponding author. Competing interests The authors declare that they have no competing interests. Funding Not applicable Authors' contributions Conceptualization: [Min Hoan Moon], [Jeong Yeon Cho]; Methodology: [Min Hoan Moon], [Sohee Oh]; Formal analysis and investigation: [Myoung Seok Lee], [Min Hoan Moon], [Taek Min Kim], [Sohee Oh]; Data curation: [Siwon Jang]; Writing - original draft preparation: [Myoung Seok Lee]; Writing - review and editing: [Min Hoan Moon], [Taek Min Kim]; Validation: [Taek Min Kim], [Jeong Yeon Cho]; Resources: [Siwon Jang]; Supervision: [Jeong Yeon Cho] Acknowledgements Not applicable References Siegel RL, Miller KD, Jemal A. (2018) Cancer statistics, 2018. CA: a cancer journal for clinicians 68 (1):7–30. doi: 10.3322/caac.21442 . Beddy P, O'Neill AC, Yamamoto AK, Addley HC, Reinhold C, Sala E. FIGO staging system for endometrial cancer: added benefits of MR imaging. 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Gynecol Oncol. 2006;102(2):343–7. doi: 10.1016/j.ygyno.2005.12.028 . Bhargavan M, Kaye AH, Forman HP, Sunshine JH. Workload of radiologists in United States in 2006–2007 and trends since 1991–1992. Radiology. 2009;252(2):458–67. doi: 10.1148/radiol.2522081895 . Harolds JA, Parikh JR, Bluth EI, Dutton SC, Recht MP. Burnout of Radiologists: Frequency, Risk Factors, and Remedies: A Report of the ACR Commission on Human Resources. J Am Coll Radiol. 2016;13(4):411–6. doi: 10.1016/j.jacr.2015.11.003 . Chetlen AL, Chan TL, Ballard DH, Frigini LA, Hildebrand A, Kim S, Brian JM, Krupinski EA, Ganeshan D. Addressing Burnout in Radiologists. Acad Radiol. 2019;26(4):526–33. doi: 10.1016/j.acra.2018.07.001 . Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About In Review Editorial Policies 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-1718202","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research article","associatedPublications":[],"authors":[{"id":121629426,"identity":"a1590d67-2b18-4e25-b4b8-eefd5b3d863c","order_by":0,"name":"Myoung Seok Lee","email":"","orcid":"","institution":"Seoul National University Seoul Metropolitan Government Boramae Medical Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Myoung","middleName":"Seok","lastName":"Lee","suffix":""},{"id":121629427,"identity":"09dcaa54-8c82-4e6d-b903-730701ab0032","order_by":1,"name":"Min Hoan Moon","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAqUlEQVRIiWNgGAWjYFACHhBhA8SMjQdI0ZIG0tJAkpbDYCZxWnSnnT344OeO83Zr2w8DbamxiSaoxex2XrJh75nbydvOJAK1HEvLbSCsJcdMgrftdrLZAaAWxobDxGmR/Nt2Ltns/EMStEjzth2wM7tBgi3GxrJtyQlmN4C2JBDpF8OHb9vs7M3Opz988KHGhrAWGEgEq0wgVjkI2JOieBSMglEwCkYYAAAc/0gYNitGfQAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-2448-2895","institution":"SMG-SNU Boramae Medical Center, Seoul National University College of Medicine","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Min","middleName":"Hoan","lastName":"Moon","suffix":""},{"id":121629428,"identity":"247ab41e-3542-4ec1-8e49-9a0e040b12f5","order_by":2,"name":"Taek Min Kim","email":"","orcid":"","institution":"Seoul National University Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Taek","middleName":"Min","lastName":"Kim","suffix":""},{"id":121629429,"identity":"26502ca0-1414-4548-a163-60703a65c62f","order_by":3,"name":"Siwon Jang","email":"","orcid":"","institution":"Seoul National University Seoul Metropolitan Government Boramae Medical Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Siwon","middleName":"","lastName":"Jang","suffix":""},{"id":121629430,"identity":"31ff2f05-d9c3-4cfe-bad0-8dbf933b0052","order_by":4,"name":"Sohee Oh","email":"","orcid":"","institution":"Seoul National University Seoul Metropolitan Government Boramae Medical Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Sohee","middleName":"","lastName":"Oh","suffix":""},{"id":121629431,"identity":"8a2cc8d6-4f14-4e75-8122-4300320ac134","order_by":5,"name":"Jeong Yeon Cho","email":"","orcid":"","institution":"Seoul National University Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jeong","middleName":"Yeon","lastName":"Cho","suffix":""}],"badges":[],"createdAt":"2022-06-02 06:44:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1718202/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1718202/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":24059168,"identity":"ac06eb4b-3d6a-45e9-9d6b-5f7310961fbf","added_by":"auto","created_at":"2022-07-19 19:43:24","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":758265,"visible":true,"origin":"","legend":"\u003cp\u003eSequential dynamic CE MRI images from A to H. A was obtained simultaneously with the administration of contrast material and subsequent sequential dynamic CE MRI images were obtained with a time resolution of 38 seconds. An endometrial mass invading less than half of the myometrium is shown in the right anterior uterine corpus (arrowheads in E). The SI difference ratio calculated from E was 0.20. Two intramural myomas are shown in the right anterior uterine corpus (arrows in F).\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-1718202/v1/7f7a3f71ade5791093c195cc.png"},{"id":24059169,"identity":"fc7e61e9-a477-4285-bc53-ff920fd2071d","added_by":"auto","created_at":"2022-07-19 19:43:24","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":436601,"visible":true,"origin":"","legend":"\u003cp\u003eSingle-phase CE MRI data(A) reconstructed into coronal (B), sagittal (C), and oblique axial (D) images. On the oblique axial image (D), invasion of more than half of the myometrium is shown in the left posterior uterine corpus (arrowheads). Intramural myomas are seen in the uterine fundus (open arrows in C and D) and anterior uterine corpus (arrow in D). * = endometrial cancer.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-1718202/v1/cedb34db6792c538d4ebf259.png"},{"id":24059167,"identity":"8fbc6faf-012d-4670-88d3-5e2d16b8d849","added_by":"auto","created_at":"2022-07-19 19:43:24","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":229581,"visible":true,"origin":"","legend":"\u003cp\u003ePlots of the two one-sided test results showing the absolute differences in the tumor-myometrium signal intensity difference ratios between single-phase CE MRI and dynamic CE MRI. The mean differences (squares) and their 90% CIs (horizontal lines) are within the equivalence margin of 0.05 (vertical dashed lines) for all readers.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-1718202/v1/11d024037037c0bd56ef0925.png"},{"id":28982770,"identity":"3ae478a8-42f0-41f9-a166-8bd5cfd13803","added_by":"auto","created_at":"2022-11-12 12:15:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1490421,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1718202/v1/e0d19d2b-dfc4-4f6a-80be-40350a36a76d.pdf"}],"financialInterests":"","formattedTitle":"Contrast-enhanced MRI in women with endometrial cancer: dynamic versus single-phase acquisitions","fulltext":[{"header":"Background","content":"\u003cp\u003eEndometrial cancer, the most common gynecologic malignancy in developed countries [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], is surgically staged according to the 2009 Federation of Gynecology and Obstetrics (FIGO) system, which includes evaluations of metastasis to the pelvic and paraaortic lymph nodes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Lymphadenectomy has been considered part of the surgical staging procedure; however, most surgeons believe that lymphadenectomy is not necessary for women at a low risk of lymph node metastasis, and not performing lymphadenectomy avoids its concomitant risks and complications [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The European Society for Medical Oncology (ESMO) recently recommended that the surgical staging of endometrial cancer should be tailored based on the risk of lymph node metastasis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. According to the ESMO guidelines, lymphadenectomy is not recommended in low-risk patients with grade 1 or 2 endometrioid adenocarcinoma without deep myometrial invasion.\u003c/p\u003e \u003cp\u003eMagnetic resonance imaging (MRI) is the most preferred imaging modality used to stratify women with endometrial cancer into low-risk versus intermediate- to high-risk groups because it is the modality that best determines the depth of myometrial invasion [\u003cspan additionalcitationids=\"CR6 CR7\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan additionalcitationids=\"CR10 CR11\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. T2-weighted imaging (T2WI), contrast-enhanced imaging, and diffusion weighted imaging (DWI) are key MRI sequences to assess myometrial invasion of endometrial cancer. Of these, contrast-enhanced MRI (CE MRI) is mostly performed as high-temporal-resolution, dynamic CE MRI [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan additionalcitationids=\"CR15 CR16\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, high-spatial-resolution, single-phase CE MRI is also an option. Our prior experience with dynamic CE MRI suggested that the temporal window for tumor-myometrium contrast in endometrial cancer is not narrow enough to require dynamic CE MRI [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Since radiologists invest substantial time and effort into reviewing hundreds of dynamic CE MRI images, it needs to be clarified whether high temporal resolution is required for CE MRI in women with endometrial cancer. Therefore, our study was conducted to evaluate whether high temporal resolution is required for contrast-enhanced MRI in women with endometrial cancer by comparing dynamic CE MRI with single-phase CE MRI.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e This retrospective, single-institutional comparative study was approved by our institutional review board, and the requirement for informed consent was waived due to the retrospective nature of the study.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy population\u003c/h2\u003e \u003cp\u003eBefore May 2014, our institution conducted dynamic CE MRI as a standard part of preoperative MRI for endometrial cancer. Based on scientific evidence [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], we adopted single-phase CE MRI instead of dynamic CE MRI in May 2014. We retrospectively searched our database for women who underwent single-phase CE MRI and surgically proven endometrial cancer, and the last 30 consecutive women were selected as the single-phase CE MRI group. Among women who underwent dynamic CE MRI and had surgically proven endometrial cancer, 30 age- and surgicopathologic stage-matched women were chosen for comparison as the dynamic CE MRI group. A deviation of \u0026plusmn;\u0026thinsp;3 years was allowed for age matching.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eImage acquisition\u003c/h2\u003e \u003cp\u003eThe MRI studies were performed with a 1.5-T MRI unit (Achieva and Intera; Philips Medical Systems, Best, the Netherlands) using a phased-array torso coil. The patients were asked to fast for 4\u0026ndash;6 hours and empty the bladder before MRI to reduce motion artifacts [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In addition, half an hour before MRI, the patients received an intramuscular injection of 20 mg of scopolamine butylbromide (Buscopan; Boehringer Ingelheim Korea, Seoul, Korea) as an antiperistaltic agent.\u003c/p\u003e \u003cp\u003eOur MRI protocol for endometrial cancer is summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. A fat-saturated T1-weighted three-dimensional fast field echo sequence was used for both dynamic CE MRI and single-phase CE MRI. For dynamic CE MRI (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), oblique axial images were obtained perpendicular to the endometrial cavity, and the scan percentage was reduced to 60% to allow a temporal resolution of 25\u0026ndash;40 seconds depending on the uterine size. The loss of image resolution from the reduced scan percentage was compensated with the peripheral part of the k-space of the last dynamic reference scan [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Imaging began simultaneously with the administration of 0.1 mmol gadolinium/kg body weight, injected at a rate of 2 mL/s through an antecubital vein, and approximately 7\u0026ndash;12 continuous sets of image series were acquired during 4\u0026ndash;6 minutes of examination. For single-phase CE MRI (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), coronal images were obtained with a slice thickness of 1 mm and a space of 0.5 mm. Because single-phase CE MRI required an average of 4 minutes and 40 seconds, a linear profile order was used to fill the central k-space with an appropriate imaging delay [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The obtained coronal data were immediately reconstructed into sagittal, coronal, and oblique axial planes by the technologists at the console and then transferred to the picture archiving and communication system (PACS: Marosis M-view, Infinitt, Seoul, Korea). A 2-mm thickness and no interslice gap were chosen to facilitate comparison with the standard anatomic sequences. The average time for image reconstruction was approximately 1 minute.\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\u003eImaging parameters of standardized MRI protocols for endometrial cancer.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSequence\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eT2 TSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eT1 TSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDWI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eDynamic \u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSingle-phase \u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePlane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSagittal\u003c/p\u003e \u003cp\u003eAxial\u003c/p\u003e \u003cp\u003eObl\u003csup\u003e1\u003c/sup\u003e axial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAxial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e(Obl\u003csup\u003e1\u003c/sup\u003e) axial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eObl\u003csup\u003e1\u003c/sup\u003e axial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCoronal\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBandwidth (Hz)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e250\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e250\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e190\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e189.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRepetition time (ms)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e620\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2420\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u0026ndash;6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEcho time (ms)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u0026ndash;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFlip angle (\u003csup\u003eo\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSense factor\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\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2/1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEcho train length\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17\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\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSlice thickness (mm)\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\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003espace (mm)\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\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of signal average\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\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eField of view (cm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMatrix\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e256*256\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e256*256\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100*100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e356*356\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e252*250\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eScan time (min:sec)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3:10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3:00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4:00\u0026ndash;6:00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4:40\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eNote-TSE\u0026thinsp;=\u0026thinsp;turbo spin-echo, DWI\u0026thinsp;=\u0026thinsp;diffusion weighted imaging, CE MRI\u0026thinsp;=\u0026thinsp;contrast-enhanced MRI\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e\u003csup\u003e1\u003c/sup\u003e Obl indicates oblique, and oblique axial images were obtained perpendicular to the endometrial cavity.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eImage analysis\u003c/h2\u003e \u003cp\u003eFor each woman included in this study, the MR images were loaded to a dedicated study worklist on the PACS after the removal of personal identifying information by an author (***) who did not participate in subsequent image interpretation. Two genitourinary radiologists (*** [reader 1] and *** [reader 2] with 4 years and 15 years of experience in genitourinary imaging, respectively) and one fourth-year resident (*** [reader 3]), who were informed of the primary aim of the study but blinded to the surgicopathologic results of each patient, independently evaluated the dynamic CE MRI and single-phase CE MRI in a random order, with reference to the T2WI and DWI sequences, for the following: (a) the tumor-myometrium signal intensity (SI) difference ratio, (b) the depth of myometrial invasion (superficial vs. deep) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], and (c) image quality. Image quality was scored according to a 4-point grading system (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), and the SI difference ratio was calculated as follows: SI difference ratio = (SI\u003csub\u003em\u003c/sub\u003e \u0026ndash; SI\u003csub\u003ec\u003c/sub\u003e) /(SI\u003csub\u003em\u003c/sub\u003e + SI\u003csub\u003ec\u003c/sub\u003e), where SI\u003csub\u003em\u003c/sub\u003e is the signal intensity of the myometrium, and SI\u003csub\u003ec\u003c/sub\u003e is the signal intensity of the endometrial cancer. This formula provides a unitless parameter between 0 and 1, with 1 representing the greatest relative contrast. For dynamic CE MRI, the SI difference ratio was calculated from the images that showed the largest subjective contrast difference between the tumor and the myometrium. Myometrial invasion was scored as superficial if the tumor showed no invasion or invasion of less than half of the myometrium, while deep myometrial invasion was defined as invasion of at least half of the myometrium [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In addition, subendometrial enhancement (SEE) on dynamic CE MRI was assessed by consensus between readers 1 and 2 with the following classification: (a) no demonstrable SEE, (b) disrupted SEE, and (c) intact SEE [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The number of images was counted by reader 2 for subsequent analysis.\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\u003eGrading of diagnostic image quality\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eScore\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDiagnostic quality\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDescription\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eExcellent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eClear depiction of the uterus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAdequate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMinor artifact that did not interfere with image interpretation\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQuestionable\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eImpaired depiction of the uterus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNondiagnostic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eInsufficient image quality\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 \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eHistopathologic analysis\u003c/h2\u003e \u003cp\u003eMost of the study participants (n\u0026thinsp;=\u0026thinsp;57) underwent standard operations consistent with the current International FIGO surgicopathologic staging and guidelines (pelvic washing for cytologic analysis, total abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymphadenectomy with or without paraaortic lymphadenectomy) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Lymphadenectomy was omitted in the remaining three women according to the clinicians\u0026rsquo; discretion. Surgicopathologic reports were prospectively provided as part of daily practice by one of four staff pathologists who were blinded to the results of the MRI studies, with a prescribed form that included the depth of myometrial invasion.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analyses were performed with MedCalc (version 18.6, MedCalc Software, Mariakerke, Belgium). To test the equivalence of the tumor-myometrium SI difference ratio between single-phase CE MRI and dynamic CE MRI, two one-sided tests for independent means were used with a margin of 0.05 [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], which was inferred from the interquartile range of the SI difference ratio in a previous study [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The diagnostic performance in the assessment of deep myometrial invasion was compared using the area under the receiver operating characteristic curve (AUC). The image quality and the number of images were compared using the Wilcoxon rank-sum test. A \u003cem\u003eP\u003c/em\u003e value of less than 0.05 was considered to indicate a statistically significant difference. Interobserver agreement was assessed using the weighted kappa (κ) statistic with the following categories: a κ value of less than 0 indicated poor agreement, a κ value of 0\u0026ndash;0.20 indicated slight agreement, a κ value of 0.21\u0026ndash;0.40 indicated fair agreement, a κ value of 0.41\u0026ndash;0.60 indicated moderate agreement, a κ value of 0.61\u0026ndash;0.80 indicated substantial agreement, and a κ value of 0.81-1.0 indicated near perfect agreement.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eIn all 60 women (mean age: 56\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\pm\\)\u003c/span\u003e\u003c/span\u003e10 years in the dynamic CE MRI group and 57\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\pm\\)\u003c/span\u003e\u003c/span\u003e9 years in the single-phase CE MRI group), pathologic confirmation of endometrial cancer was obtained following hysterectomy. The specimens showed no invasion or invasion of less than half of the myometrium in 42 women and invasion of half or more of the myometrium in 18 women. The surgicopathologic characteristics of the study participants are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The median interval between MRI and surgery was 11 days (95% confidence interval [CI]: 7\u0026ndash;76 days) in the dynamic CE MRI group and 10 days (95% CI: 7\u0026ndash;11 days) in the single-phase CE MRI group.\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\u003eSurgicopathologic characteristics of the study participants\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDynamic \u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSingle-phase \u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHistologic subtype\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndometrioid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24 (80.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26 (86.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSerous papillary\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMucinous\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClear cell\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSquamous\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUndifferentiated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMixed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (1.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (1.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHistologic grade\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWell differentiated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11 (36.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (53.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModerately differentiated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (40.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (33.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePoorly differentiated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (20.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (6.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNot determined\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (6.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMyometrial invasion\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo or less than half\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21 (70.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21 (70.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEqual to or more than half\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (30.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (30.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurgical stage\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (60.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (13.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eII\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (13.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (13.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIIIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (13.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIIIB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIIIC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (13.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (10.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIVA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIVB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eNote: Data represent numbers of women, with percentages in parentheses.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eSI difference ratio\u003c/h2\u003e \u003cp\u003eFor reader A, the SI difference ratio of dynamic CE MRI ranged from 0.03 to 0.42, with a median value of 0.18, while that of single-phase CE MRI ranged from 0.04 to 0.33, with a median value of 0.20. For reader B, the SI difference ratio of dynamic CE MRI ranged from 0.04 to 0.42, with a median value of 0.22, while that of single-phase CE MRI ranged from 0.06 to 0.36, with a median value of 0.21. For reader C, the SI difference ratio of dynamic CE MRI ranged from 0.06 to 0.45, with a median value of 0.22, while that of single-phase CE MRI ranged from 0.07 to 0.31, with a median value of 0.22. The dynamic and single-phase CE MRI SI difference ratios were found to be equivalent for all readers with a margin of equivalence of 0.05 (90% CI of the mean difference: -0.0497 to 0.0165, -0.0226 to 0.0403, and \u0026minus;\u0026thinsp;0.0429 to 0.0433, respectively, for readers A, B, and C) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eDiagnostic performance\u003c/h2\u003e \u003cp\u003eThe sensitivity and specificity of dynamic and single-phase CE MRI in the detection of deep myometrial invasion are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and the AUCs in the detection of deep myometrial invasion are presented in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. For all readers, the difference in the AUC between dynamic and single-phase CE MRI was not significant (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.3315, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.3345, and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.8593, respectively, for readers A, B, and C). The interobserver agreement in the diagnosis of deep myometrial invasion was substantial for dynamic CE MRI and moderate to substantial for single-phase CE MRI (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSensitivity and specificity of dynamic CE MRI and single-phase CE MRI in the detection of deep myometrial invasion in women with endometrial cancer.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eReader\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eSensitivity (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eSpecificity (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDynamic\u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSingle-phase\u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDynamic\u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSingle-phase\u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReader A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e67 (6/9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e89 (8/9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e86 (18/21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e86 (18/21)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReader B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e44 (4/9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78 (7/9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e95 (20/21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e86 (18/21)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReader C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e44 (4/9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e44 (4/9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e86 (18/21)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e90 (19/21)\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\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAUC values for dynamic CE MRI and single-phase CE MRI in the detection of deep myometrial invasion in women with endometrial cancer.\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=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReader\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDynamic\u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSingle-phase \u003c/p\u003e \u003cp\u003eCE MRI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReader A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.762 (0.572\u0026ndash;0.897)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.873 (0.701\u0026ndash;0.966)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.3315\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReader B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.698 (0.504\u0026ndash;0.851)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.817 (0.634\u0026ndash;0.934)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.3345\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReader C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.651 (0.456\u0026ndash;0.815)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.675 (0.480\u0026ndash;0.833)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.8593\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e* Data are AUC values, with 95% CIs in parentheses.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eNote-AUC\u0026thinsp;=\u0026thinsp;area under the curve.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eInterobserver agreement of dynamic CE MRI and single-phase CE MRI in the evaluation of deep myometrial invasion.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDynamic CE MRI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSingle-phase CE MRI\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eA vs. B\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.64 (0.33\u0026ndash;0.95)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.63 (0.34\u0026ndash;0.92)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eA vs. C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.66 (0.36\u0026ndash;0.96)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.60 (0.31\u0026ndash;0.89)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eB vs. C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.79 (0.52-1.00)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.50 (0.17\u0026ndash;0.83)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e* Data are κ values, with 95% CIs in parentheses.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eSubendometrial enhancement\u003c/h2\u003e \u003cp\u003eSEE was depicted in only 30.0% (9/30) of women who underwent dynamic CE MRI, and SEE was demonstrated in 17.7% (1/6) of premenopausal women who were eligible for fertility-sparing management. In all cases, SEE was disrupted and no women showed intact SEE.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eImage quality\u003c/h2\u003e \u003cp\u003eFor reader A, the image quality of dynamic CE MRI ranged from 1 to 4, with a median score of 3, while that of single-phase CE MRI ranged from 2 to 4, with a median score of 3. For reader B, the image quality of dynamic CE MRI ranged from 1 to 4, with a median score of 3, while that of single-phase CE MRI ranged from 2 to 4, with a median score of 3. For reader C, the image quality of dynamic CE MRI ranged from 1 to 3, with a median score of 3, while that of single-phase CE MRI ranged from 2 to 4, with a median score of 3. For all readers, image quality was significantly better for single-phase CE MRI than for dynamic CE MRI (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0143, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0042, and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0066, respectively, for readers A, B, and C).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eNumber of images\u003c/h2\u003e \u003cp\u003eThe number of images for dynamic CE MRI ranged from 350 to 880, with a median of 640, while that for single-phase CE MRI ranged from 112 to 300, with a median of 270. The median number of images was 2.4 times higher for dynamic CE MRI than for single-phase CE MRI, and the difference was statistically significant (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001).\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eMoon et al. reported that an imaging delay of approximately 90 seconds after contrast material injection may be optimal to obtain appropriate tumor-myometrium contrast in women with endometrial cancer. In their study, the appropriate tumor-myometrium contrast tended to continue or increase over time and not be instantaneous [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Therefore, as long as the central \u003cem\u003ek\u003c/em\u003e-space data for tumor-myometrium contrast are obtained after an appropriate imaging delay, single-phase CE MRI can be performed without losing tumor-myometrium contrast, compared to dynamic CE MRI. In the present study, the \u003cem\u003ek\u003c/em\u003e-space profile order was set to be linear and the central lines were acquired halfway through the acquisition. By doing so, we could fill the central k-space data 2 or 3 minutes after contrast material injection because the acquisition of single-phase CE MRI took approximately 4\u0026ndash;6 minutes. As expected, the tumor-myometrium SI difference ratio was not significantly different between dynamic CE MRI and single-phase CE MRI (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.2342, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.7553, and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.9410, respectively, for readers A, B, and C).\u003c/p\u003e \u003cp\u003eThe volume data for single-phase CE MRI can be reconstructed into multiple imaging planes. Using several planes was expected to improve the diagnostic performance of CE MRI in the assessment of deep myometrial invasion; however, although the performance of single-phase CE MRI was better than that of dynamic CE MRI for all readers in the present study, statistically significant differences were not demonstrated between dynamic and single-phase CE MRI (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). We assume that the use of T2WI and DWI for reference and the small number of patients in the study might have been responsible for this unexpected result, but future studies are needed to clarify our assumptions.\u003c/p\u003e \u003cp\u003eThe improved temporal resolution of dynamic CE MRI was expected to increase tumor-myometrium contrast, but as shown in the present study, dynamic CE MRI did not show better tumor-myometrium contrast than single-phase CE MRI in women with endometrial cancer. Instead, decreasing signal acquisition for spatial information led to deterioration of the image quality [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], as was also demonstrated in the present study. Another reason for performing dynamic CE MRI in women with endometrial cancer is the expectation of demonstrating SEE, which is a thin layer of enhancement between the endometrium and the myometrium [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In women with endometrial cancer, myometrial invasion can be ruled out by demonstrating an intact SEE on dynamic CE MRI, which is useful information when fertility-sparing management is under consideration [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. However, the role of dynamic CE MRI in the selection of fertility-sparing management may be limited, given that SEE cannot be demonstrated on dynamic CE MRI in many women, especially premenopausal women [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Our study also showed that SEE was not frequently demonstrated on dynamic CE MRI. Furthermore, Nakao et al. reported that eight (40%) of 20 women with intact SEE on dynamic CE MRI were eventually found to have myometrial invasion [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Given these findings, we need to reconsider whether dynamic CE MRI should be used to select women for fertility-sparing management.\u003c/p\u003e \u003cp\u003eIn the last few decades, the workload in radiology has dramatically increased with the advent of the PACS, increased utilization of advanced cross-sectional imaging with much larger sets of data, and an overall increase in the number of imaging studies [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The increasing workload has resulted in high rates of radiologist burnout, and this trend has only continued to worsen [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. In the present study, dynamic CE MRI produced 2.4 times more images than single-phase CE MRI, meaning that radiologists would need to invest more time and effort in interpreting CE MRI. Since CE MRI does not require high temporal resolution for endometrial cancer, single-phase CE MRI may be a better choice than dynamic CE MRI in the era of radiologist burnout.\u003c/p\u003e \u003cp\u003eOur study has several limitations. First, the small number of the study population and retrospective nature of the present study may have introduced bias. Second, although we tried to control for confounding variables by matching age and pathologic staging, this study could not be completely free from selection bias because we were not able to perform both dynamic CE MRI and single-phase CE MRI in the same women. The third limitation is that DWI, which has been increasingly highlighted [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], was not compared with CE MRI. We know that readers are curious about the comparison of CE MRI and DWI, but we believe that the question should be addressed after clarifying the preferable acquisition method for CE MRI. Finally, all women enrolled in the present study were scanned only with a 1.5 Tesla MRI unit. Since the magnetic field strength could affect spatial and temporal resolution, additional studies will be needed to elucidate the effects of magnetic field strength on CE MRI.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn the present study for CE MRI in women with endometrial cancer, single-phase acquisition did not impair the tumor-myometrium contrast that could be obtained by dynamic acquisition. Single-phase acquisition and dynamic acquisition showed similar diagnostic performance in the detection of deep myometrial invasion. In addition, single-phase CE MRI provided better image quality and fewer images than dynamic CE MRI. In the era of radiologist burnout, therefore, we believe that single-phase acquisition might be a better option for CE MRI than dynamic acquisition in women with endometrial cancer.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e(AUC) area under the receiver operating characteristic curve\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(CE MRI) contrast-enhanced MRI\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(CI) confidence interval\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(DWI) diffusion weighted imaging\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(ESMO)European Society for Medical Oncology\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(FIGO) Federation of Gynecology and Obstetrics\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(MRI) Magnetic resonance imaging\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(SEE) subendometrial enhancement\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(SI) signal intensity\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(T2WI) T2-weighted imaging\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEthics approval and consent to participate\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eThis retrospective, single-institutional comparative study was approved by the institutional review board of Boramae Medical Center (03-2017-12), and the requirement for informed consent was waived due to the retrospective nature of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eConsent for publication\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAvailability of data and materials\u003c/em\u003e\u003c/strong\u003e The data that support the findings of this study are available from the corresponding author, but restrictions apply to the availability of these data. Data are available from the authors upon reasonable request and with permission of the corresponding author.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eCompeting interests\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eFunding\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAuthors\u0026apos; contributions\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eConceptualization: [Min Hoan Moon], [Jeong Yeon Cho]; Methodology: [Min Hoan Moon], [Sohee Oh]; Formal analysis and investigation: [Myoung Seok Lee], [Min Hoan Moon], [Taek Min Kim], [Sohee Oh]; Data curation: [Siwon Jang]; Writing - original draft preparation: [Myoung Seok Lee]; Writing - review and editing: [Min Hoan Moon], [Taek Min Kim]; Validation: [Taek Min Kim], [Jeong Yeon Cho]; Resources: [Siwon Jang]; Supervision: [Jeong Yeon Cho]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAcknowledgements\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSiegel RL, Miller KD, Jemal A. 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Acad Radiol. 2019;26(4):526\u0026ndash;33. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.acra.2018.07.001\u003c/span\u003e\u003cspan address=\"10.1016/j.acra.2018.07.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Magnetic resonance imaging, Contrast media, Endometrial neoplasms, Uterus","lastPublishedDoi":"10.21203/rs.3.rs-1718202/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1718202/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e The 2019 ESUR guidelines for endometrial cancer recommend performing either dynamic contrast-enhanced MRI (CE MRI) or single-phase CE MRI. However, no study has directly compared these options.\u003cstrong\u003e \u003c/strong\u003eTherefore, this study compared dynamic versus single-phase CE MRI for the evaluation of myometrial invasion in women with endometrial cancer.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eThis retrospective, single-institution comparative study was conducted among women with surgically proven endometrial cancer, including 30 consecutive women with single-phase CE MRI and 30 age- and pathologic stage-matched women with dynamic CE MRI. Three readers independently compared dynamic and single-phase CE MRI in terms of the tumor-myometrium signal intensity (SI) difference ratio, depth of myometrial invasion, image quality, and image number. Pathologic findings served as a reference standard for the depth of myometrial invasion.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults.\u003c/strong\u003e The estimated mean SI difference ratios of dynamic CE MRI and single-phase CE MRI fell within an equivalence margin of 0.05 (90% confidence intervals; -0.0497 to 0.0165, -0.0226 to 0.0403, -0.0429 to 0.0433, respectively, for readers A, B, and C). The area under the receiver operating characteristic curve for the detection of deep myometrial invasion was not significantly different between the acquisitions (\u003cem\u003eP\u003c/em\u003e=0.3315, \u003cem\u003eP\u003c/em\u003e=0.3345, and \u003cem\u003eP\u003c/em\u003e=0.8593, respectively). Single-phase CE MRI showed significantly better image quality than dynamic CE MRI (\u003cem\u003eP\u003c/em\u003e=0.0143, \u003cem\u003eP\u003c/em\u003e=0.0042, and \u003cem\u003eP\u003c/em\u003e=0.0066, respectively), while the median number of images for dynamic CE MRI was 2.4 times higher than that for single-phase CE MRI.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusions. \u003c/strong\u003eSingle-phase acquisition may be a better option for CE MRI in women with endometrial cancer than dynamic acquisition.\u0026nbsp;\u003c/p\u003e","manuscriptTitle":"Contrast-enhanced MRI in women with endometrial cancer: dynamic versus single-phase acquisitions","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-07-19 19:43:22","doi":"10.21203/rs.3.rs-1718202/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"aadc543a-27f3-4b09-8984-c4d02e9430e5","owner":[],"postedDate":"July 19th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-11-12T12:15:33+00:00","versionOfRecord":[],"versionCreatedAt":"2022-07-19 19:43:22","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1718202","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1718202","identity":"rs-1718202","version":["v1"]},"buildId":"pf3fE39SIOqb-0xH_OWvX","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}