Toshiro Kuroiwa

MRI of groove pancreatitis.

PURPOSE The purpose of this work is to describe the findings on MRI in patients with groove pancreatitis, a specific form of chronic pancreatitis affecting the groove between the pancreatic head, the duodenum, and the common bile duct. METHOD MR images, including MR cholangiopancreatography, of five patients with groove pancreatitis were reviewed. Three patients underwent pancreatoduodenectomy due to serve duodenal stenosis, and the MR findings were compared to the histologic findings. RESULTS A sheet-like mass was demonstrated between the pancreatic head and the duodenum in all patients. The masses were hypointense relative to pancreatic parenchyma on T1-weighted images and iso- to slightly hyperintense on T2-weighted images. After administration of Gd-DTPA, the masses showed delayed enhancement. Histologically, fibrous scar tissue was detected in the groove. CONCLUSION MR images can clearly demonstrate the fibrous tissue in the groove in groove pancreatitis, and MR cholangiopancreatography can also provide useful information.

Efficacy of Helical Ct in T-staging of Gastric Cancer

PURPOSE The purpose of this study was to evaluate the performance of helical CT in preoperative T-staging in patients with gastric cancer. METHOD A total of 71 patients with an established diagnosis of gastric cancer [75 lesions, 46 early (T1) and 29 advanced (T2 or more) cancers] were evaluated with helical CT. Helical CT was performed with 5-mm slice thickness at 5-mm/s table incrementation. Using the volumetric data by helical scanning, axial CT images (5-mm slice thickness at 5-mm intervals) and multiplanar reconstruction (MPR) images were obtained. CT findings were compared with histopathologic studies of the resected specimen. RESULTS Sensitivity of helical CT for gastric cancer was 26% (12 of 46) for early and 100% (29 of 29) for advanced cancer. Three lesions were misdiagnosed as gastric cancer by helical CT. Histopathologically, all early gastric cancers detected by helical CT were either polypoid or elevated types or showed massive invasion of the submucosal layer. The differentiation between T1 cancer with massive submucosal invasion and advanced cancer was difficult. The differentiation between T2 and T3 cancer was possible in 73% (19 of 26) and between T1/T2 and T3/T4 (extraserosal invasion) in 83% (34 of 41). Overall T-staging was correct in 66% (27 of 41). MPR images improved the detection rate (three lesions) or increased confidence in T-staging (eight lesions) over axial CT images. CONCLUSION When helical CT detected gastric cancer that was not a polypoid or elevated type with underlying normal-appearing gastric wall, it was either T1 cancer with massive invasion of the cancer cells into the submucosal layer or advanced cancer. However, differentiation between these two stages was difficult on CT. Diagnosis of serosal invasion was not markedly improved by helical CT. MPR images increased confidence in the staging of certain gastric cancers, such as those in locations where CT images are susceptible to partial volume averaging effects.

Radiologic diagnosis of adenomyomatosis of the gallbladder: comparative study among MRI, helical CT, and transabdominal US.

Purpose The goal of this work was to evaluate the diagnostic accuracy of transabdominal ultrasound (US), helical CT, and MRI in the diagnosis of adenomyomatosis (ADM) of the gallbladder. Method Twenty patients with surgically proven ADM were included, all of whom underwent preoperative US, helical CT with 3 mm collimation, and MRI with half-Fourier rapid acquisition with relaxation enhancement (RARE). All images were retrospectively reviewed by two radiologists, and the presence of ADM was assessed at three compartments (neck, body, and fundus) of the organ. Receiver operating characteristic analysis was performed, and sensitivity, specificity, and accuracy were calculated for each modality. Results The A z values (area under the curve) for MRI, helical CT, and US were 0.98, 0.85, and 0.72 for the Reader 1, respectively, showing no statistically significant interobserver difference in any of the three modalities. MRI showed a significantly higher A z value than helical CT or US (p < 0.1). The accuracies of MRI, helical CT, and US were 93, 75, and 66%, respectively. Conclusion Among the three modalities tested, MRI with half-Fourier RARE sequence was the most accurate for diagnosing ADM.

Computed tomographic findings of Bellini duct carcinoma of the kidney.

OBJECTIVE To analyze CT findings of Bellini duct carcinoma, a rare variant of renal cell carcinoma. MATERIALS AND METHODS The CT findings of five cases of Bellini duct carcinoma were reviewed and the findings were recorded. RESULTS In all cases the affected kidneys maintained the normal outer contours. In four cases the renal masses protruded into the central sinuses. Contrast enhancement was minimal in four cases. CONCLUSION Bellini duct carcinoma should be suspected in cases with these CT findings.

Dysembryoplastic neuroepithelial tumors: MR findings.

Objective We report MR findings in three patients with dysembryoplastic neuroepithelial tumor (DNT), which is a recently described benign tumor in childhood or young adolescents. Materials and Methods The MR studies of three patients with surgically proven DNT were reviewed. All cases presented with partial complex seizures. Axial and coronal T1− and T2-weighted MR imaging of the head was performed using a 1.5 T MR unit. T1-weighted imaging after Gd-DTPA was also performed. Results The tumors were located mainly in the cortical to subcortical area with very little perifocal mass effects on MR imaging. They were essentially hypointense on T1-weighted imaging and hyperintense well-demarcated mass on T2-weighted imaging and retained a thick gyrus-like configuration within the lesions. None of them exhibited contrast enhancement after administration of Gd-DTPA. Conclusion Differentiation of DNT from gangliogliomas or other low grade gliomas is possible using these MR features and is important because DNT does not recur after epilepsy surgery, therefore postoperative radiation and chemotherapy are not needed.

Autopsy report of primary CNS B-cell lymphoma indistinguishable from multiple sclerosis: diagnosis with the immunoglobulin gene rearrangements analysis

We report a case of primary CNS B-cell lymphoma indistinguishable from multiple sclerosis (MS). MRI of the head showed the spontaneous disappearance of the white matter lesions and the progressive cerebral atrophy. The brain biopsy failed to make a diagnosis of CNS lymphoma but rather suggested MS. Although the primary CNS lymphoma was suspected at autopsy, the immunohistochemical study showed the CNS-infiltrating lymphoid cells comprising both T-cells and B-cells. Analysis of the immunoglobulin and T-cell receptor gene rearrangements first provided evidence of primary CNS B-cell lymphoma.