Objectives: (1) To evaluate the diagnostic performance of the VI-RADS score in detecting muscle invasion in variant urothelial carcinomas (VUC). (2) To identify spesific MRI features that may serve as predicting for VUC. Methods: Two hundred four patients who underwent TUR-B and/or radical cystectomy and a bladder mpMRI scan within three months prior to the procedure were retrospectively enrolled. The tumors were divided into two histological cohorts: pure urothelial carcinoma (PUC) and VUC. Various MRI features, including largest tumor diameter, long-to-short axis ratio, morphology, heterogeneous signal intensity (SI), presence of necrosis, and normalized ADC (ADC_n) value, were analyzed. The diagnostic performance of the VI-RADS score in predicting muscle invasion was calculated using a cut-off point of ≥ 4 in both cohorts. Univariate logistic regression were also performed to identify MRI features that predict VUC. Inter-reader agreement was assessed with the weighted kappa coefficient. Results: Our study identified several MRI features significantly associated with VUC, including heterogeneous SI on T2-weighted images (OR: 3.055; 95% CI: 1.312–7.112; p < 0.001), dynamic contrast enhancement images (OR: 2.935; 95% CI: 1.263–6.821; p < 0.001), and the presence of necrosis (OR: 3.575; 95% CI: 1.798–7.107; p < 0.001). Additionally, ADC_n values were significantly lower in the VUC cohort (p = 0.003). The VI-RADS score demonstrated high diagnostic performance across both VUC and PUC cohorts, with sensitivity ranging from 94.4 to 86.8% (reader 1) and 94.2–82.2% (reader 2), specificity ranging from 100 to 94.6% (reader 1) and 100–94% (reader 2), and accuracy ranging from 96 to 90.6% (reader 1) and 96–88.2% (reader 2). The area under the curve (AUC) ranged between 0.972 and 0.972 (reader 1) and 0.838–0.781 (reader 2). No significant differences in diagnostic performance were observed between readers or cohorts (p > 0.05), and inter-reader agreement for VI-RADS scores was excellent for both cohorts. Conclusion: VI-RADS score can be used with high performance to detect muscle invasion in VUC, regardless of reader experience. Additionally, specific MRI features such as heterogeneous SI, the presence of necrosis, and ADC_n values can serve as potential predictors of VUC. Graphical

Introduction: The aim of this study is to assess the risk of peroneal artery injury of hardware placement at the fixation of syndesmotic injuries. Materials and methods: The lower extremity computed tomography angiography was used to design the study. The syndesmosis screw placement range was simulated every 0.5 cm, from 0.5 to 5 cm proximal to the ankle joint. The screw axes were drawn as 20°, 30° or individual angle according to the femoral epicondylar axis. The proximity between the screw axis and the peroneal artery was measured in millimeters. Potential peroneal artery injury was noted if the distance between the peroneal artery to the axis of the simulated screw was within the outer shaft radius of the simulated screw. The Pearson chi-square test was used and a p-value < 0.05 was considered significant. Results: The potential for injury to the peroneal artery increased as the syndesmosis screw level rose proximally from the ankle joint level or as the diameter of the syndesmosis screw increasds. In terms of syndesmosis screw trajection, the lowest risk of injury was observed with the syndesmosis screw angle of 20°. Simulations with a screw diameter of 3.5 mm exhibited the least potential for peroneal artery injury. Conclusion: Thanks to this radiological anatomy simulation study, we believe that we have increased the awareness of the peroneal artery potential in syndesmosis screw application. Each syndesmosis screw placement option may have different potential for injury to the peroneal artery. To decrease the peroneal artery injury potential, we recommend the followings. If individual syndesmosis screw angle trajection can be measured, place the screw 1.5 cm proximal to the ankle joint using a 3.5 mm screw shaft. If not, fix it with 30° trajection regardless of the screw diameter at the same level. If the most important issue is the peroneal artery circulation, use the screw level up to 1 cm proximal to the ankle joint regardless of the screw angle trajection and screw diameter.

Background: Schwannoma, also known as neurinoma, is the most common tumor of the peripheral nerves. Intrascrotal extratesticular schwannoma, which is not associated with schwannomatosis and neurofibromatosis-2, is a very rare entity and few cases have been reported in the literature. In this paper, we reported our case of extratesticular schwannoma, an extremely rare cause of scrotal mass, with ultrasound (US) and magnetic resonance imaging (MRI) findings. Case Report: A 22-year-old male presented with painless left scrotal swelling. Scrotal US showed an extra-testicular heterogeneous hypoechoic mass with lobulated contour in inferior part of scrotum. Scrotal MRI demonstrated well-defined extratesticular mass, which showed heterogeneous hypointens on T2 weighted-images compared with testis parenchyma. On contrast enhanced images, mass showed mild-modarate enhancement. The patient was underwent to surgery with the preliminary diagnosis of benign intrascrotal extratesticular mass. The lesion was removed with preservation of the testicles by urologists, and final diagnosis was made as scrotal schwannoma by histological and immunohistochemical examination Conclusion: Although there is no specific imaging finding of scrotal schwannoma, MRI can be used as a guide to surgery by helping to accurately determine whether the lesion is intra- or extratesticular. In addition, radiologists and urologists should keep schwannoma in mind in the differential diagnosis in the presence of an intrascrotal extratesticular mass.