Memory impairment caused by cerebral hematoma in the left medial temporal lobe due to ruptured posterior cerebral artery aneurysm

BACKGROUND: Cognitive disorders, such as memory disturbances, are often observed following a subarachnoid hemorrhage. We present a very rare case where rupture of a posterior cerebral artery aneurysm caused restricted damage to the hippocampus unilaterally, and caused memory disturbances. CASE PRESENTATION: A 56-year-old, right-handed man, with a formal education history of 16 years and company employees was admitted to our hospital because of a consciousness disturbance. He was diagnosed as having a subarachnoid hemorrhage due to a left posterior cerebral artery dissecting aneurysm, and coil embolization was performed. Subsequently, he had neither motor paresis nor sensory disturbances, but he showed disorientation, and both retrograde and anterograde amnesia. Although immediate recall and remote memory were almost intact, his recent memory was moderately impaired. Both verbal and non-verbal memories were impaired. Brain computed tomography (CT) and magnetic resonance imaging (MRI) revealed a cerebral hematoma in the left temporal lobe involving the hippocampus and parahippocampal gyrus, and single-photon emission computed tomography (SPECT) demonstrated low perfusion areas in the left medial temporal lobe. CONCLUSIONS: We suggest that the memory impairment was caused by local tissue destruction of Papez’s circuit in the dominant hemisphere due to the cerebral hematoma

2D-Time of Flight MR Angiography in Intrathoracic Masses

正常ボランティア5例, 胸部腫瘤性病変の患者15例に対してMR Angiographyを施行した.MRAは, 6秒の息、止めでFLASH法(TR=20msec, TE=8msec, Flip angle=30°)を用いて撮像した像から作成した.全ての症例で胸部大動脈, 上大静脈, 下大静脈, 肺動脈及び肺静脈根部など太い血管の明瞭なMRA像が得られ, 腫瘤とそれら大血管系との関係が把握しやすく胸部腫瘤性病変の評価に有用と考えられた.MR Angiography of the thorax was performed in 5 healthy volunteers and 15 patients with intrathoracic masses. 2D-MRA was obtained sequentially by means of a fast low angle shot(FLASH)technique(TR=20msec.TE=8msec, Flip angle=30within a 6-second period of breath holding. MRA for great vessels was successfully completed in all volunteers and all patients. The relation between tumor and vasculature can be visualized so definitely that MRA may be thought to be a promising complement to MR imaging in the evaluation of intrathoracic masses

Endometrial Polyps:MR Imaging Features

The purpose of this study is to evaluate the diagnostic usefulness of magnetic resonance imaging (MRI) characteristics of endometrial polyps in order to differentiate them from other endometrial lesions. MRI was retrospectively reviewed in 40 patients with pathologically proven endometrial polyps. Special attention was paid to the sizes, shapes, margins, internal structures, signal intensities, and post-contrast enhancement patterns. A central fibrous core, intratumoral cysts, and hemorrhage were seen in 30 (75%), 22 (55%), and 14 (35%) patients, respectively. The predominant signal intensity of the lesions showed iso-to slightly low signal intensity relative to the endometrium on T2-weighted images in 36 (90%), low signal intensity on diffusion-weighted images in 32 (80%), and strong or moderate enhancement on enhanced T1-weighted images in 28 patients (70%), respectively. In 32 (80%) patients, the endometrial polyps showed global or partial early enhancement. On dynamic study, rapid enhancement with a persistent strong enhancement pattern was seen in 17 (42.5%) and a gradually increasing enhancement pattern was seen in 17 patients (42.5%). These MRI features can be helpful to distinguish the endometrial polyps from various other endometrial lesions

Basic Study of Susceptibility-Weighted Imaging at 1.5T

With the aim of sequence optimization in susceptibility-weighted imaging (SWI), 2 image acquisition parameters (slice thickness and matrix size) and 2 image processing conditions (number of slices per minimum intensity projection (MIP) and Sliding Window) were investigated using a 1.5-T magnetic resonance imaging (MRI) system. The subjects were 12 healthy volunteers and the target region for scanning was the whole brain. Informed consent was obtained from all subjects. First, susceptibility-weighted images were acquired with various slice thicknesses from 1mm to 5mm and various matrix sizes from 256x256 to 512x512, and the images were assessed in terms of the contrast-to-noise ratio (CNR) and were also visually evaluated by three radiologists. Then, the number of slices per MIP and the usefulness of the Sliding Window were investigated. In the study of the optimal slice thickness and matrix size, the results of visual evaluation suggested that a slice thickness of 3mm and a matrix size of 448x448 are optimal, while the results of evaluation based on CNR were not significant. As regards the image processing conditions, the results suggested that the number of slices per MIP should be set to a minimum value of 2 and that the use of Sliding Window is effective. The present study provides useful reference data for optimizing SWI sequences.</p

Estimation of identification limit for a small-type OSL dosimeter on the medical images by measurement of X-ray spectra

Our aim in this study is to derive an identification limit on a dosimeter for not disturbing a medical image when patients wear a small-type optically stimulated luminescence (OSL) dosimeter on their bodies during X-ray diagnostic imaging. For evaluation of the detection limit based on an analysis of X-ray spectra, we propose a new quantitative identification method. We performed experiments for which we used diagnostic X-ray equipment, a soft-tissue-equivalent phantom (1–20 cm), and a CdTe X-ray spectrometer assuming one pixel of the X-ray imaging detector. Then, with the following two experimental settings, corresponding X-ray spectra were measured with 40–120 kVp and 0.5–1000 mAs at a source-to-detector distance of 100 cm: (1) X-rays penetrating a soft-tissue-equivalent phantom with the OSL dosimeter attached directly on the phantom, and (2) X-rays penetrating only the soft-tissue-equivalent phantom. Next, the energy fluence and errors in the fluence were calculated from the spectra. When the energy fluence with errors concerning these two experimental conditions was estimated to be indistinctive, we defined the condition as the OSL dosimeter not being identified on the X-ray image. Based on our analysis, we determined the identification limit of the dosimeter. We then compared our results with those for the general irradiation conditions used in clinics. We found that the OSL dosimeter could not be identified under the irradiation conditions of abdominal and chest radiography, namely, one can apply the OSL dosimeter to measurement of the exposure dose in the irradiation field of X-rays without disturbing medical images

Spontaneous Regression of Colonic Lesions in Adult T-cell Leukemia

A 74-year-old man was admitted to our hospital because of diarrhea. Serum anti-HTLV-1 antibody was positive without abnormal lymphocytes. Colonoscopy demonstrated a edematous and congested mucosa with erosions, and ulcers in the region extending from the cecum to rectum. Biopsy specimens showed diffuse infiltration of abnormal lymphocytes positive for T-cell markers in the lamina propria. Conservative therapy was provided but no chemotherapy because of improvement of diarrhea within two weeks. A repeat colonoscopy 6 months later revealed scars without erosions or ulcers. Eight months after first admission, the patient was readmitted to our hospital because of acute ATL crisis, and died of hepatic involvement 7 days later. Colonic lesions associated with ATLS may show spontaneous regression and recurrence