Positional cranial deformity due to sustained external pressure during infancy frequently improves in early childhood; however, its prevalence in adulthood, particularly in East Asian populations, remains unclear. The authors performed a retrospective cross-sectional analysis of thin-slice cranial computed tomography (CT) images from 242 Japanese individuals aged 15 to 39 years who underwent cranial CT at a single tertiary hospital from 2014 to 2023 and had no intracranial abnormalities. Using the cranial vault asymmetry index (CVAI) and cephalic index (CI), cranial morphology was measured on standardized reconstructed images. The median CVAI was 3.94 (interquartile range, 1.99-6.28); of the participants, 129 (53.3%) met criteria for plagiocephaly, and 46 (19.0%) had moderate-to-severe deformity. Brachycephaly prevalence was 1.6% using Japanese reference-based criteria but 72.3% using international anthropometric-based criteria. Males exhibited a higher CVAI than females; however, no difference in the CVAI and CI was noted by birth year before versus after introducing Japan's Back-to-Sleep campaign. Both indices demonstrated excellent interrater reliability. The observed prevalence of plagiocephaly in this Japanese emergency department CT cohort indicates that plagiocephaly remains common among Japanese young adults, with a significant proportion exhibiting moderate-to-severe deformity, and that infant sleep positioning practices alone do not fully account for its prevalence. The marked discrepancy between Japanese and international criteria suggests that population-specific reference values may be more appropriate for assessing brachycephaly in Japanese adults. This finding is crucial for counseling caregivers and informing treatment decisions for infants with positional cranial deformities.

Lobular endocervical glandular hyperplasia (LEGH), a benign multicystic lesion that typically occurs in the upper uterine cervix, is regarded as a potential precursor lesion of gastric-type adenocarcinoma (GAS), including its well-differentiated form, minimal deviation adenocarcinoma (MDA). On MRI, LEGH characteristically shows the “cosmos sign,” consisting of clustered small central cysts surrounded by larger peripheral cysts on T2-weighted images. However, MDA arising from LEGH can yield similar findings. Differentiation by MRI is therefore often challenging. This report describes two premenopausal women with MDA associated with previously diagnosed LEGH who underwent serial MRI follow-up. In both cases, T2-weighted images showing the cosmos sign revealed progressive enlargement of a central hypointense area with concomitant shrinkage of the surrounding cysts. Neither showed any readily apparent increase in overall lesion size. During follow-up after the initial diagnosis/conization, cytology remained negative for intraepithelial lesion or malignancy. In case 1, hysterectomy revealed MDA associated with previously diagnosed LEGH. The central hypointense area corresponded to tumor-associated reactive fibrotic stroma containing infiltrative glands with nuclear enlargement and mitoses. In case 2, hysterectomy showed deeply extending, morphologically diverse glands associated with reactive fibrotic stroma suspicious for invasion. The central hypointense area again corresponded to predominantly fibrotic stroma. These cases suggest that progressive expansion of a central low-signal-intensity area on T2-weighted images, accompanied by shrinkage of peripheral cysts, might constitute an early imaging sign of transition from LEGH to MDA, even without overall LEGH enlargement or worsening cytology. Such expansion should therefore be assessed carefully on follow-up MRI.

OBJECTIVE:To clarify the qualitative and quantitative MRI features of myxoid leiomyosarcoma (MLMS) in comparison with conventional leiomyosarcoma (cLMS) and to identify the specific diagnostic pitfalls of the current consensus criteria when applied to the MLMS subtype. MATERIALS AND METHODS:This retrospective multicenter study (12 institutions) included patients with histopathologically confirmed leiomyosarcoma (MLMS or cLMS) who underwent preoperative MRI. A total of 38 women (15 with MLMS and 23 with cLMS; median age, 55 years) were evaluated. Three radiologists independently evaluated features, including T2 signal patterns (purely hyperintense, mixed, iso-to-moderately hyperintense) and a characteristic "marbled appearance" (heterogeneous signal intermingling). The tumors were classified as benign or malignant on the basis of the apparent diffusion coefficient (ADC) values in accordance with the current consensus criteria. A histogram analysis was performed using multiparametric sequences. RESULTS:MLMS frequently exhibited purely T2-hyperintense or mixed patterns (12 of 15 [80%]), whereas cLMS predominantly showed T2-isointensity to moderate hyperintensity (21 of 23 [91%]) (P < 0.001). The "marbled appearance" was identified in 11 of 15 (73%) MLMS cases and 2 of 23 (9%) cLMS cases (P < 0.001). Median ADC values of the most restricted component were significantly higher in MLMS (1.14 × 10⁻³ mm²/s) than in cLMS (0.80 × 10⁻³ mm²/s) (P < 0.001). Consequently, the consensus ADC criteria misclassified 10 of 12 (83%) MLMS cases as benign, in comparison with 3 of 21 (14%) cLMS cases (P < 0.001). Notably, among these 10 misclassified MLMS cases, 8 (80%) demonstrated the "marbled appearance." Histogram analysis confirmed that patients with MLMS had higher median normalized T2-weighted imaging signal intensity ratios (1.97 vs. 1.36; P = 0.019) and ADC ratios (1.39 vs. 0.82; P = 0.007). CONCLUSION:Strict reliance on ADC-based consensus criteria may lead to systematic under-recognition of MLMS. Recognizing the "marbled appearance" on MRI is crucial to prevent misclassifying these tumors as benign.

BACKGROUND:Subamniotic or subchorionic hematoma (SAH/SCH) is associated with diverse pregnancy outcomes. The clinical implications of accompanying oligohydramnios and hemorrhagic amniotic fluid on MRI remain unclear. PURPOSE:To investigate the importance of oligohydramnios and hemorrhagic amniotic fluid on placental MRI for SAH/SCH in risk stratification. STUDY TYPE:Retrospective. POPULATION:Seventy-one singleton pregnancies with SAH/SCH identified on placental MRI performed during the second or third trimesters, from 2016 to 2023. FIELD STRENGTH/SEQUENCE:1.5 T, Fat-saturated T1-weighted gradient echo and half-Fourier-acquired single-shot turbo spin echo sequences. ASSESSMENT:Cases were classified into three groups: Groups A (oligohydramnios and hemorrhagic amniotic fluid), B (either oligohydramnios or hemorrhagic amniotic fluid), and C (SAH or SCH only). Groups B and C were subclassified as B-1 (oligohydramnios), B-2 (hemorrhagic amniotic fluid), C-1 (detected hematoma on ultrasound before MRI), and C-2 (incidentally detected hematoma on MRI). Unfavorable obstetric outcome (abortion or birth before 34 gestational weeks) and neonatal outcome (duration of neonatal intensive care unit [NICU] stay) were compared. STATISTICAL TESTS:Fisher's exact test, Kruskal-Wallis test, Mann-Whitney U test, and Kaplan-Meier analysis with Log-rank test. Significance was determined at p < 0.05. RESULTS:Unfavorable obstetric outcomes were significantly higher in Group A (11/12, 91.7%) than groups B (6/17, 35.3%) and C (9/42, 21.4%). Significant differences were found among the five subclassified groups, most notably between B-1 and B-2. The median duration of NICU stay was 87, 30.5, 0, 25, and 8 days in Groups A (n = 12), B-1 (n = 5), B-2 (n = 12), C-1 (n = 11), and C-2 (n = 31), respectively. Group A showed the worst neonatal outcomes. DATA CONCLUSION:MRI findings of oligohydramnios and/or hemorrhagic amniotic fluid in pregnancies with SAH/SCH are associated with adverse obstetric and neonatal outcomes, supporting risk stratification. EVIDENCE LEVEL:4. TECHNICAL EFFICACY:Stage 5.

The purpose of this study was to compare the diagnostic performance of radiolabeled prostate-specific membrane antigen-targeted positron emission tomography/computed tomography (PSMA-PET/CT) with 18F, whole-body magnetic resonance imaging (WB-MRI), including diffusion-weighted imaging (DWI) and a combination of conventional computed tomography and bone scintigraphy (CT/BS) for the detection of recurrent lesions in patients with prostate cancer with rising PSA levels following initial definitive treatment. This retrospective study used part of the dataset from a previous phase 2 study conducted between February 2019 and March 2022, which evaluated the detection efficacy of 18F-FSU-880 PSMA-PET/CT in 72 patients with suspected recurrent prostate cancer after definitive treatment. Of these, 35 patients (age 56–82 years, PSA level 0.24–40.00 ng/ml) who underwent both PSMA-PET/CT and WB-MRI were reviewed by six radiologists. Sensitivity, specificity, and overall accuracy were compared using McNemar’s test, and positive predictive value was compared using Fisher’s exact test. Total 132 true-positive prostate cancer lesions were detected in 23 of 35 patients (66

OBJECTIVE:In the differential diagnosis between uterine fibroids and uterine sarcomas, real-world magnetic resonance imaging (MRI) diagnostic information is scarce; furthermore, high diagnostic sensitivity is important in clinical practice. We previously developed a diagnostic algorithm to detect uterine sarcoma with high sensitivity using simple MRI images and serum lactate dehydrogenase (LDH) levels. In this multicenter study, we investigated the preoperative diagnosis of sarcoma in the real world and further validated the usefulness of our diagnostic algorithm. METHODS:Of 154 uterine sarcomas and 154 uterine fibroids treated at 15 centers between January 2006 and December 2020, 139 sarcomas (16 smooth muscle tumors of uncertain malignant potential) and 141 fibroids with diffusion-weighted imaging information were included in the analysis. The diagnostic algorithm was validated by 3 radiologists who were blinded to the clinical information and pathologic diagnoses and who read the MRIs. RESULTS:The sensitivity/specificity of preoperative diagnosis was 77.7%/92.9% for the preoperative report; 92.1%/72.3% for algorithm A; and 82.0%/85.8% for algorithm B (McNemar's test p<0.05). Comparison of overall survival rates among 3 groups (Group 1: negative A, Group 2: positive A and negative B; Group 3: positive B) using algorithms A and B showed p=0.012. On multivariate analysis, stage, and serum LDH level were independent prognostic factors. CONCLUSION:MRI is useful for preoperative diagnosis of uterine sarcoma, and the sarcoma diagnostic algorithm presented in this study is an option for diagnosing sarcoma with greater sensitivity. This information should be shared with patients.

As one of the key pillars of work style reform for physicians, task shifting and sharing from radiologists to radiological technologists has been considered. In May 2021, the Radiological Technologists Act was amended, allowing for the expansion of several duties. Alongside these legal and regulatory changes, a notice from Ministry of Health, Labour and Welfare was issued, highlighting tasks to be particularly promoted under the current system prior to the amendment of the Radiological Technologists Act. These amendments authorize radiological technologists to perform advanced and specialized tasks, such as securing venous access for contrast agent administration, which require significantly higher skill levels than their traditional roles. However, the amended legislation did not include specific guidelines, rules, or considerations for the practical implementation of these new duties in daily medical practice, especially from the perspectives of patient safety and quality of care. To address this, the Japan Radiological Society, the Japanese College of Radiology, and the Japan Association of Radiological Technologists collaborated with other related societies to develop guidelines on five key topics:-Guidelines for Safe Conduct of CT/MRI Contrast-Enhanced Examinations: Considering the expanded scope of practice for radiological technologists. -Guidelines for Safe Conduct of Nuclear Medicine Examinations: Aligned with the expanded responsibilities of radiological technologists. -Guidelines for Clinical application of Image-Guided Radiation Therapy (IGRT). -Guidelines for Safe Conduct of Angiography and Interventional Radiology (IR): Adapted for the expanded roles of radiological technologists. -Guidelines for Reporting Findings of STAT Imaging: Addressing urgent conditions with potential impact on life prognosis.

Placental insufficiency is a critical condition in perinatal medicine, clinically manifesting as fetal growth restriction or preeclampsia. In addition to ultrasound and Doppler velocimetry, MRI has been assessed intensively for its potential to evaluate placental function directly. Several methods investigated to date include anthropometry, visual assessments using T2-weighted images, and quantitative evaluations based on T2 values, hypoxia indicators (T2* values and blood oxygenation level-dependent imaging), and perfusion metrics (intravoxel incoherent motion and arterial spin labeling). Anthropometry and visual assessments are easily implemented clinically because they require no specific technique or post-processing. By contrast, quantitative approaches provide objective numerical indicators, making them promising imaging biomarkers. Despite their potential, translating these methods into clinical practice presents challenges, especially for quantitative techniques, because of limited availability, lack of standardization, and inadequate clinician awareness. This review was conducted to overview the clinical aspects of placental insufficiency, summarize the anthropometry, visual assessments, and quantitative methods reported, and highlight the latest advancements. It also presents discussion of related challenges and future prospects for clinical implementation.

Cervical cancer treatment involves multidisciplinary care teams composed of gynecologic surgeons, gynecologic oncologists, radiation oncologists, pathologists, and radiologists. The 2018 update of the FIGO cervical cancer staging system incorporated imaging as a source of staging information, reflecting the critical role of imaging in evaluating patients with cervical cancer before and after therapy. However, the lack of standardized terminology has led to challenges in the updated system's application, including ambiguity in management decisions. This collaborative project between the Society of Abdominal Radiology Uterine and Ovarian Cancer Disease-Focused Panel, the European Society of Urogenital Radiology Female Pelvic Imaging Working Group, and the Asian Society of Abdominal Radiology aimed to develop a list of standardized consensus-based terms and definitions for reporting imaging findings in the initial staging, follow-up, and treatment planning of cervical cancer, as well as a report template leveraging the lexicon terms. The lexicon and report template were developed by 20 committee members (17 radiologists, two gynecologic oncologic surgeons, and one radiation oncologist), representing 19 institutions from North America, Europe, and Asia. These tools are intended to improve consistency in the reporting of cervical cancer imaging, to enhance communication among care teams and optimize patient management.

To summarize the key updates introduced in the 2023 International Federation of Gynecology and Obstetrics (FIGO) classification for endometrial cancer (EC), and to highlight the role of MRI in aligning with these changes for improved staging and patient management. A review of the updated 2023 FIGO classification, which integrates molecular profiling and histopathological criteria, was conducted. Additionally, the revised European Society of Urogenital Radiology (ESUR) MRI recommendations were analyzed to assess their alignment with the new FIGO framework, focusing on their role in evaluating myometrial invasion (MI) and cervical stromal involvement. The updated FIGO classification incorporates molecular data to refine risk stratification and staging accuracy. MRI continues to play a pivotal role in distinguishing between stages, mapping disease extent, and guiding surgical planning. The updated ESUR recommendations emphasize standardized MRI protocols, particularly the use of multiphase contrast-enhanced imaging, to improve diagnostic confidence in assessing MI. The integration of molecular classification into FIGO staging, supported by standardized and advanced MRI protocols as recommended by ESUR, enhances the management of endometrial cancer. Question The 2023 FIGO update integrates molecular profiling into endometrial cancer staging, requiring MRI adaptations to improve accuracy in assessing disease extent, including myometrial invasion. Findings Updated ESUR MRI guidelines emphasize multiphase contrast-enhanced imaging, structured reporting, and integration with FIGO 2023 classification, enhancing diagnostic precision for staging and treatment planning. Clinical relevance Standardized MRI protocols aligned with FIGO 2023 system improve endometrial cancer staging, guiding optimal surgical and therapeutic strategies, reducing diagnostic variability, and enhancing patient outcomes through individualized risk stratification and personalized treatment.

Survivors of hereditary retinoblastoma have increased risk of subsequent primary malignancies due to RB1 mutation. We report uterine leiomyosarcoma (LMS) in a hereditary retinoblastoma survivor. She had follow-up for leiomyomas, with pelvic MRI showing typical leiomyomas two years prior. She presented with abdominal distention, and MRI revealed a massive tumor with LMS characteristics where a leiomyoma was previously observed. Chest CT showed a nodule suspicious for metastasis in the left lung. Total hysterectomy with bilateral salpingo-oophorectomy and partial lung resection was performed. Pathology confirmed LMS with pulmonary metastasis. Immunostaining showed complete RB1 loss in tumor cells. LMS was suspected to have arisen near a pre-existing leiomyoma or resulted from its malignant transformation. Continuous follow-up is necessary in hereditary retinoblastoma survivors.

This study was conducted to identify MRI features distinguishing uterine adenosarcoma from endometrial polyps and to predict the presence or absence of sarcomatous overgrowth (SO), a pathological finding linked to poor prognosis. This multicenter retrospective study included 11 cases of uterine adenosarcoma, with 5 showing SO and 6 without, and 20 cases of endometrial polyps measuring 3 cm or greater diameter. Quantitative evaluations (tumor volume, cystic lesion size, diffusion-weighted imaging [DWI] signal ratio, apparent diffusion coefficient [ADC] value, and normalized ADC value) and qualitative evaluations (degree of hemorrhage, signal intensity on T2-weighted imaging and DWI, number of cystic lesions, degree of contrast enhancement, and tumor localization) were performed. The evaluation parameters were compared between uterine adenosarcoma and endometrial polyp groups, and between SO and non-SO subgroups within uterine adenosarcoma. Uterine adenosarcoma had significantly larger tumor volumes (median 192,324 mm³ vs. 15,717 mm³, p < 0.001), larger cystic lesions (median 17.7 mm vs. 6.7 mm, p = 0.0074), and higher DWI signal ratios (median 1.50 vs. 1.08, p = 0.008) along with significantly lower ADC values (median 961.5 × 10− 6 mm²/s vs. 1222.3 × 10− 6 mm²/s, p = 0.048) and normalized ADC values (median 0.34 vs. 0.49, p = 0.001) compared to endometrial polyps. Gross hemorrhage (9/11 vs. 1/20, p < 0.001) and high signal intensity on DWI (10/11 vs. 4/20, p < 0.001) were observed more frequently with uterine adenosarcomas. No significant difference was found between uterine adenosarcomas with SO and without SO for any quantitative or qualitative evaluation parameter. This study identified key imaging features of uterine adenosarcoma, including larger tumor volume, larger cystic lesions, gross intratumoral hemorrhage, higher DWI signal intensity, and lower ADC values. These findings can facilitate preoperative differentiation of uterine adenosarcoma from endometrial polyps. Uterine adenosarcoma shows larger tumor size, larger cystic lesions, and gross hemorrhage, compared to endometrial polyps. Uterine adenosarcoma shows higher DWI signal intensity with lower ADC values, indicating higher cellular density. No significant MRI differences were found between uterine adenosarcoma cases with and without sarcomatous overgrowth, requiring further study.

OBJECTIVE:Adenomyosis, a common gynecologic disease, can cause infertility. Uterine peristalsis (UP) is a wave-like contraction. Abnormal UP has been linked to infertility. The aim of this study using magnetic resonance imaging (MRI) was to compare UP between uterine walls with adenomyosis and normal walls to ascertain the possible effects of adenomyosis on UP. METHODS:Using cine MRI, UP of 139 adenomyosis patients were evaluated. The uterine walls were divided into those with and without lesions. One radiologist evaluated the presence of UP depending on the menstrual cycle phase. In cases where peristalsis was present, the peristaltic frequency and direction were evaluated. For uterine walls with adenomyosis, characteristic movement of peristalsis was evaluated, including low signal conduction, change of endometrial configuration, and irregular signal change. Peristalsis was evaluated further between focal and diffuse adenomyosis. RESULTS:UP was observed significantly more in adenomyosis lesions (113/182) than in normal myometrium (47/96), especially in the luteal phase, but the frequency was not significantly different (6.9 vs. 7.3). Comparison between diffuse adenomyosis and focal adenomyosis revealed that the presence of peristalsis was not significantly different in any cycle phase. Peristaltic direction was observed as cervix-to-fundus in the proliferative and luteal phase. Almost half of the cases showed low signal conduction (48%-59%), change of endometrial configuration (31%-53%), and irregular signal change (41%-56%) in adenomyosis lesions. CONCLUSION:UP in adenomyosis showed a tendency of hyperperistalsis in the luteal phase. It accompanies characteristic peristaltic movement in adenomyosis in about half of patients.

To investigate the age-related changes in magnetic resonance imaging (MRI) findings of lobular endocervical glandular hyperplasia (LEGH) during long-term follow-up. This multicenter study included 91 patients who underwent preoperative MRI and had a histopathological diagnosis of LEGH, atypical LEGH, or adenocarcinoma in situ (AIS) with LEGH after surgical resection. Thirty patients underwent follow-up MRIs at intervals of more than 3 months. According to the age and menopausal status, patients were categorized into four groups: group A, 31–40 years; group B, 41–50 years (premenopausal); group C, more than 50 years (premenopausal); group D, postmenopausal. Differences in the MRI findings (size and morphological pattern) were compared among the four groups. The lesion volume was the largest in group C and smallest in group D, showing a statistically significant difference (p < 0.05). The typical cosmos pattern was seen in 60.0

Endometrial cancer (EC) is projected to become the third most common cancer and the fourth leading cause of cancer-related deaths among women by 2040, with the most substantial increases observed in non-Hispanic Black, Hispanic, and Asian populations. The International Federation of Gynecology and Obstetrics (FIGO) 2023 classification introduces key updates, including a refined staging system incorporating molecular markers for improved risk stratification. MRI plays a critical role in treatment planning by evaluating the extent of the disease, determining eligibility for fertility-preserving options, guiding radiotherapy planning, and supporting follow-up care. It is also essential for distinguishing EC from cervical cancer. Notable revisions in the FIGO 2023 staging guidelines focus on assessing myometrial invasion, identifying synchronous or metastatic ovarian tumors, and evaluating peritoneal involvement. Recurrence typically occurs within the first 2 years, with common sites including the vaginal vault and lymph nodes, where MRI remains the preferred imaging modality. While CT is routinely employed to assess metastatic disease, 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT is valuable for detecting nodal and distant metastases. Additionally, some institutions have begun using 18F-FDG PET/MRI to evaluate both local recurrence and distant metastases, offering a more integrated approach for EC follow-up.

The purposes of the study are to assess the diagnostic performance of preoperative imaging for staging factors in gastric-type endocervical adenocarcinoma (GEA) and to compare the performance for GEA with that of usual-type endocervical adenocarcinoma (UEA) among patients preoperatively deemed locally early stage (DLES) (< T2b without distant metastasis). For this multi-center retrospective study, 58 patients were enrolled. All had undergone MRI with or without CT and FDG PET-CT preoperatively and had been pathologically diagnosed with GEA at five institutions. Based on the medical charts and radiological reports, the diagnostic performances of preoperative imaging for the International Federation of Gynecology and Obstetrics staging factors were assessed retrospectively. Next, the imaging performance was assessed in preoperatively DLES-GEA (n = 36) and DLES-UEA (n = 136, with the same inclusion criteria). The proportions of underestimation of GEA and UEA were compared using Fisher’s exact test. Imaging diagnostic performance for GEA was limited, especially for sensitivity: parametrial invasion, 0.49; vaginal invasion, 0.54; pelvic lymph node metastasis (PELNM), 0.48; para-aortic lymph node metastasis, 0.00; and peritoneal dissemination, 0.25. Among preoperatively DLES patients, the proportions of underestimation were significantly higher in GEA than in UEA; parametrial invasion, 35

Purpose:We retrospectively investigated spatial pattern associations between primary and recurrent tumor sites after definitive external-beam radiation therapy (EBRT) for prostate cancer, using positron emission tomography/computed tomography (PET/CT) with a prostate-specific membrane antigen (PSMA)-targeted probe, 18F-FSU-880. Methods and Materials:We used data from our prior phase 2 trial involving patients who received PET/CT with 18F-FSU-880, which was designed to evaluate the tumor detection efficacy of PSMA-PET/CT for recurrent prostate cancer. Data from patients with local intraprostatic recurrence detected by PSMA-PET/CT after definitive EBRT were retrospectively analyzed. The prostate and seminal vesicles were divided into 14 sections. Two diagnostic radiologists separately re-evaluated the intraprostatic location of the primary tumor on magnetic-resonance imaging and that of the recurrent tumor on PSMA-PET/CT, respectively, and the rate of overlap between primary and recurrent tumors was calculated. The overlap rate was defined as "the number of sections that overlapped between the primary tumor and recurrent tumor" divided by "the total number of sections of recurrent tumor". A recurrent tumor was considered to be at the same location as the primary tumor when the overlap rate was equal to or greater than 75%, and a partial overlap was defined as an overlap rate between 25 and 74%. Results:Twelve patients had local recurrence detected by PSMA-PET/CT. The median time to diagnosis of local recurrence was 9.1 (range, 2.2-12.3) years after definitive EBRT. The recurrent tumor was detected at the same location in 25.0%, and a partial overlap was noted in 41.7%. Conclusions:Local intraprostatic recurrence after definitive EBRT often occurs at the same site or at a partially overlapping site adjacent to the primary intraprostatic dominant lesion. Our results support the merit of focal dose-escalation for intraprostatic dominant lesions in definitive EBRT.

Rationale and objectives: To develop and validate a deep learning (DL) model to automatically diagnose muscle-invasive bladder cancer (MIBC) on MRI with Vision Transformer (ViT). Materials and methods: This multicenter retrospective study included patients with BC who reported to two institutions between January 2016 and June 2020 (training dataset) and a third institution between May 2017 and May 2022 (test dataset). The diagnostic model for MIBC and the segmentation model for BC on MRI were developed using the training dataset with 5-fold cross-validation. ViT- and convolutional neural network (CNN)-based diagnostic models were developed and compared for diagnostic performance using the area under the curve (AUC). The performance of the diagnostic model with manual and auto-generated regions of interest (ROImanual and ROIauto, respectively) was validated on the test dataset and compared to that of radiologists (three senior and three junior radiologists) using Vesical Imaging Reporting and Data System scoring. Results: The training and test datasets included 170 and 53 patients, respectively. Mean AUC of the top 10 ViT-based models with 5-fold cross-validation outperformed those of the CNN-based models (0.831 ± 0.003 vs. 0.713 ± 0.007–0.812 ± 0.006, p < .001). The diagnostic model with ROImanual achieved AUC of 0.872 (95 % CI: 0.777, 0.968), which was comparable to that of junior radiologists (AUC = 0.862, 0.873, and 0.930). Semi-automated diagnosis with the diagnostic model with ROIauto achieved AUC of 0.815 (95 % CI: 0.696, 0.935). Conclusion: The DL model effectively diagnosed MIBC. The ViT-based model outperformed CNN-based models, highlighting its utility in medical image analysis.

Background and PurposeThe main feeding artery of a dural arteriovenous fistula (DAVF) involving the superior sagittal sinus (SSS) is the middle meningeal artery (MMA). MMA extends continuously from the proximal part to SSS in DAVF involving SSS. It is possible to diagnose DAVF involving SSS by evaluating the proximal part of MMA on routine three-dimensional time-of-flight MR angiography (MRA). We termed the finding in an anteroposterior maximum intensity projection (MIP) image of routine MRA in which MMA was continuously visualized at the top of the imaging slab (the upper corpus callosum level) without tapering as the MMA sign. The purpose of the present study was to examine the frequency of the MMA sign on routine MRA in patients with DAVF involving SSS and control patients.Materials and MethodsSubjects comprised 18 patients with DAVF involving SSS confirmed by angiography and 871 control subjects who underwent routine MRA. The presence of the MMA sign was retrospectively evaluated using an anteroposterior MIP image of routine MRA in patients with DAVF involving SSS and control patients.ResultsThe MMA sign was observed in 17 of the 18 (94%) patients with DAVF involving SSS. In one patient with DAVF involving the posterior part of SSS without the MMA sign, the main feeding artery was the occipital artery, not MMA. The MMA sign was observed in 13 of the 871 (1.5%) control patients.ConclusionThe MMA sign on routine MRA is useful, suggesting DAVF involving SSS.