Akihito Mitsumori

Struma ovarii: appearance on MR images

Abstract.Background: The purpose of this multi-institutional study was to examine the appearance of struma ovarii on magnetic resonance (MR) images. Methods: MR images of 12 patients with histologically proven struma ovarii were retrospectively reviewed. All patients underwent T1-weighted and T2-weighted imaging. Contrast-enhanced T1-weighted images with Gd-DTPA were available in 10 patients. The following determinations were made: tumor morphology, signal intensities, contrast-enhancement effects of solid components with Gd-DTPA, and comparison of MR images with resected specimens. Results: All 12 patients had both cystic and solid components, with a multilobulated surface and thickened septa. Signal intensities on T1-weighted images were mainly low, partly intermediate to high, or high, and those on T2-weighted images were mainly high, with different signal intensities. Contrast-enhancement effects were marked or moderate. The contents that showed low signal intensities on T1-weighted images and signal voids or low signal intensities on T2-weighted images were viscid gelatinous materials. Conclusions: A multicystic tumor with a solid component, a multilobulated surface, and signal intensities that indicate the presence of viscid gelatinous materials appear to be a characteristic MR finding of struma ovarii.

I-123 uptake in nonfunctional struma ovarii

A case of nonfunctional struma ovarii preoperatively diagnosed by scintigraphy of the pelvis using I-123 NaI is reported. US, CT, and MRI revealed a multilobulated mass composed of cystic and solid components. CT showed cystic components with slightly high density and MRI showed various signal intensities on T1- and T2-weighted images. I-123-scintigraphy of the pelvis showed uptake in the pelvic mass. Microscopic examination revealed the histologic appearance of thyroid tissue accompanied by follicular adenoma. I-123 scintigraphy of the pelvis was useful for reaching the correct preoperative diagnosis in this patient with nonfunctional struma ovarii.

Uterine cirsoid aneurysm : MRI and MRA

Uterine cirsoid aneurysm is uncommon. It is important to make a diagnosis of this disease preoperatively, because repeated curettages may induce life-threatening massive genital bleeding. We present a case of a 51-year-old woman with uterine cirsoid aneurysm in whom MRI and MRA were very useful for the preoperative diagnosis. The radiologic appearances on ultrasonography, CT, conventional SE MRI, MRA, dynamic MRI, and pelvic angiography are presented. Conventional SE T1-weighted and T2-weighted images demonstrated multiple flow voids in the uterus and bilateral adnexal regions. MRA demonstrated a cluster of distinct, tortuous, and coiled vascular channels in the pelvis. MRA could obtain images almost equal to angiography and was considered to be an excellent noninvasive imaging technique for the diagnosis of uterine cirsoid aneurysm.

MR appearance of adenomatoid tumor of the uterus.

Reports on the radiological findings of adenomatoid tumor of the uterus are rare, and preoperative diagnosis is very difficult. To our knowledge, there have been no reports concerning the MR findings of adenomatoid tumor of the uterus. We report two cases of uterine adenomatoid tumor that showed the characteristic features of leiomyoma on MR images.

Reduced radioactivity in the periphery of the liver in a patient with idiopathic portal hypertension.

The authors report a case of idiopathic portal hypertension in which radioaccumulation in the peripheral region of the liver decreased markedly. On dynamic CT, peripheral regional enhancement of the liver was seen in the arterial phase. The region was hypointense on T1-weighted MR images and hyperintense on T2-weighted images. On portograms via the superior mesenteric artery, markedly decreased portal venous perfusion was seen in the peripheral region of the liver. Tc-99m galactosyl human serum albumin (GSA) liver scintigrams showed decreased accumulation in the peripheral region and unchanged accumulation in the central region of the liver. Tc-99m GSA liver scintigraphy clearly showed localized liver dysfunction in the peripheral region.

Sclerosing stromal tumor of the ovary with atypical magnetic resonance imaging findings in a middle-aged woman

We encountered a case of atypical sclerosing stromal tumor of the ovary (SST) in a middle-aged woman. This 52-year-old woman presented with a 2-year history of abdominal distention. Magnetic resonance imaging (MRI) showed a large mass extending from the pelvis to the epigastrium. T2-weighted MRI showed an island-shaped area of slight hyperintensity. Dynamic MRI demonstrated gradual light enhancement of the area in which T2-weighted imaging showed low intensity. The diagnosis of the tumor proved difficult because neither MRI findings nor the age of getting sick were atypical. We report this case with MRI findings and correlated pathology.

MRI Findings of Inverted Urothelial Papilloma of the Bladder

OBJECTIVE The objective of this study was to characterize MRI findings of inverted urothelial papilloma of the bladder. MATERIALS AND METHODS Data pertaining to 16 patients with 18 pathologically proven inverted urothelial papillomas of the bladder who had undergone MRI were retrospectively collected from seven institutions. The shape and surface characteristics of the tumors were evaluated using T2-weighted MR images. In addition, the signal intensity of inverted urothelial papillomas was visually assessed on T1-weighted, T2-weighted, and DW images and on early and delayed phase contrast-enhanced images. RESULTS The shape of the 18 inverted urothelial papillomas of the bladder was classified as polypoid with a stalk for 16 tumors (89%) and polypoid without a stalk for two tumors (11%). All stalks were surrounded by urine in the bladder. A total of 15 of the tumor surfaces (83%) were nonpapillary and three (17%) were papillary. All 12 of the inverted urothelial papillomas for which evaluable T1-weighted images were available were isointense with the bladder wall. The lesions had a slightly higher signal intensity than the bladder wall in 15 of the patients (83%) and showed isointensity with the bladder wall in three patients (17%). A total of three patients (17%) had tiny hyperintense foci noted on T2-weighted images. All 16 of the inverted urothelial papillomas examined by DWI had very high signal intensity. All 13 of the lesions for which early phase images were obtained using dynamic contrast-enhanced MRI showed strong enhancement. When compared with early phase images, delayed phase images of the same 13 lesions showed that enhancement was stronger in two lesions (15%), similar in six lesions (46%), and weaker in five lesions (38%). CONCLUSION On MRI, the typical appearance of inverted urothelial papillomas of the bladder is a polypoid shape with a nonpapillary surface and a thin short stalk surrounded by urine. Cystic foci are also occasionally seen within the tumor.