Kouji Yamakawa

CT findings in groove pancreatitis: correlation with histopathological findings

Objective To clarify the CT characteristics of groove pancreatitis, which is a segmental form of chronic pancreatitis. Materials and Methods The CT findings in four patients with proved groove pancreatitis were reviewed retrospectively. The examinations consisted of plain CT, dynamic CT, and high dose enhancement CT in each patient. Correlation between the CT findings and the resected specimens was performed in three patients. Results In every patient a mass was detected in the head of the pancreas that involved the duodenum. Dynamic CT demonstrated a poorly enhancing lesion extending between the pancreatic head and the duodenum. Cysts in the duodenal wall and/or the groove and duodenal stenosis due to wall thickening were seen in four and three patients, respectively. These CT findings reflect the histological characteristics of this disease. Conclusion Computed tomography, including dynamic study, can demonstrate the characteristic findings of groove pancreatitis and suggest the diagnosis.

High-resolution T2-weighted MR imaging of the inner ear using a long echo-train-length 3D fast spin-echo sequence

The purpose of this study was to assess the value of a long echo-train-length 3D fast spin-echo (3D-FSE) sequence in visualizing the inner ear structures. Ten normal ears and 50 patient ears were imaged on a 1.5T MR unit using a head coil. Axial high-resolution T2-weighted images of the inner ear and the internal auditory canal (IAC) were obtained in 15 min. In normal ears the reliability of the visualization for the inner ear structures was evaluated on original images and the targeted maximum intensity projection (MIP) images of the labyrinth. In ten normal ears, 3D surface display (3D) images were also created and compared with MIP images. On the original images the cochlear aqueduct, the vessels in the vicinity of the IAC, and more than three branches of the cranial nerves were visualized in the AIC in all the ears. The visibility of the endolympathic duct was 80%. On the MIP images the visibility of the three semicircular canals, anterior and posterior ampulla, and of more than two turns of the cochlea was 100%. The MIP images and 3D images were almost comparable. The visibility of the endolymphatic duct was 80% in normal ears and 0% in the affected ears of the patients with Menieres disease (p < 0.01). In one patient ear a small intracanalicular tumor was depicted clearly. In conclusion, the long echo train length T2-weighted 3D-FSE sequence enables the detailed visualization of the tiny structures of the inner ear and the IAC within a clinically acceptable scan time. Furthermore, obtaining a high contrast between the soft/bony tissue and the cerebrospinal/endolymph/perilymph fluid would be of significant value in the diagnoses of the pathologic conditions around the labyrinth and the IAC.

Clinical evaluation of newly developed CRT viewing station: CT reading and observer's performance

The clinical performance of the new viewing station with six CRT monitors (17-inch, 1,024 x 1,280) was evaluated. In the primary interpretation of CT images, time measurements were carried out for eight radiologists. No significant differences in reading time existed between CRT and film in 3 of 4 readers in head CT series, and in 2 of 6 readers in body CT series. Compared with the previous system, the new prototype system achieved an approximately 30% decrease in reading time in both head and body CT studies and could reduce mental and eye fatigue.

A multicenter survey of stage T1 glottic cancer treated with radiotherapy delivered in 2.25-Gy fractions in clinical practice : An initial 5-year analysis

ABSTRACT The purpose of this study was to evaluate the acute and late toxicity as well as local control (LC) in T1 glottic cancer (GC) patients treated with hypofractionated radiotherapy (RT) in clinical practice. The Tokai Study Group for Therapeutic Radiology and Oncology started RT treatment with a dose of 2.25 Gy for T1 GC in 2011. Ten institutions combined data from 104 patients with T1 squamous cell carcinoma between 2011 and 2015. In total, 104 patients with T1 GC were irradiated with a standard radiation dose of 63 Gy in 28 fractions.The median follow-up duration was 18 (3.7–49.5) months. Acute grade 3 adverse events were observed in 7 patients, with 4 patients (5%) having dermatitis and 3 patients (4%) having mucositis. Late adverse events above grade 3 were not observed. Two patients developed local recurrence. The rates of acute adverse events in the present study were comparable to those in previous studies that have used 2 Gy fractions of RT.