MRI features of the nested variant of urothelial carcinoma of the urinary bladder: report of four cases.

We report on four patients with the nested variant of urothelial carcinoma (NVUC) of the urinary bladder and focus on their magnetic resonance imaging (MRI) findings. MRI showed that all lesions had irregular wall thickening with little protrusion into the bladder lumen. All had extravesical invasion, and two had invaded other organs (uterus and seminal vesicle). On T2-weighted images, all tumors mainly showed relatively strong hypointensity similar to that of the muscularis propria, and in three cases there was also a thin hyperintense layer on the tumor surface, suggesting edematous mucosa. Diffusion-weighted images demonstrated different degrees of hyperintensity, which was faint in one case. Dynamic contrast-enhanced MRI was performed in two cases and both showed gradual contrast enhancement. It has been suggested that NVUC may produce unique MRI findings reflecting its pathological features. It would be useful for those who interpret bladder MRI to recognize this rare urothelial carcinoma variant.

Susceptibility weighted MRI after uterine artery embolization for leiomyoma.

PURPOSE: To evaluate whether susceptibility-weighted MR imaging (SWI) findings are associated with tumor infarction on contrast-enhanced MRI (CE-MRI) after uterine artery embolization (UAE) for leiomyoma. METHODS: This was a single institution, retrospective study. Between February 2016 and April 2017, 27 consecutive patients underwent UAE and completed SWI and CE-MRI before and 1 week after UAE. Two blinded readers independently reviewed the MRI of 261 tumors ≥1 cm in all patients. We evaluated the relationship between the hypointense peripheral rim observed on the tumor surface on post-procedural SWI and the infarction rates (≥90%, <90%) of each tumor based on post-procedural CE-MRI. Inter-reader correlation coefficients (ICC) and the sensitivity and specificity of the rim were measured. RESULTS: Substantial inter-reader agreement was noted in post-procedural SWI interpretations (ICC = 0.681, 95% CI; 0.547, 0.771). The rim was observed in 66.7% (174/261) of tumors by reader 1 and 55.9% (146/261) of tumors by reader 2 on post-procedural SWI. Correlations were observed between the rim and ≥90% tumor infarction by readers 1 and 2 (Spearman's coefficient = 0.474 and 0.438, p < 0.001 and p < 0.001, respectively). The sensitivity and specificity of the rim to tumor infarction were 77.2 and 82.6% (reader 1), and 65.8 and 100% (reader 2), respectively. CONCLUSIONS: The present study demonstrated that the hypointense peripheral rim was observed on some leiomyomas on SWI immediately after UAE. The rim correlated with tumor infarction on post-procedural CE-MRI. This SWI finding was helpful for evaluating embolic effects on leiomyomas in the acute phase after UAE.

Isolated fallopian tube torsion diagnosed and treated with laparoscopic surgery: A case report.

Among diseases causing acute lower abdominal pain in women, isolated fallopian tube torsion is very rare, with an annual prevalence of 1 in 1.5 million. Because it has fewer findings on imaging compared to adnexal torsion, the correct diagnosis can rarely be made before an operation. We present a case of isolated fallopian tube torsion that was suspected preoperatively by its clinical course and findings on computed tomography. A 24-year-old woman repeatedly experienced acute colicky pain in the right lower back. Transvaginal ultrasonography and magnetic resonance imaging showed a right pelvic cystic lesion with intact ovaries; these findings led us to schedule a laparoscopic examination. However, the patient presented to the emergency room with acute severe right back pain. The preoperative diagnosis considering the computed tomography findings and clinical course was consistent with fallopian tube torsion. An earlier diagnosis may have helped to preserve the fallopian tube and future fertility.