Takehiko Sakakibara

Kissing aneurysms of distal anterior cerebral arteries demonstrated by magnetic resonance angiography

BACKGROUND Multiple aneurysms, associated with distal anterior cerebral artery (ACA) aneurysm, are not rare; therefore, it is important to examine multiplicity of the aneurysms preoperatively. CASE REPORT A case of ruptured distal ACA aneurysm, associated with another one in a mirror position, is reported. A 43-year-old woman suffered subarachnoid hemorrhage. Conventional angiography demonstrated a saccular aneurysm on the bifurcation of the right or left distal ACA; however, magnetic resonance angiography (MRA) revealed two mirror-image aneurysms on both bifurcations. CONCLUSION MRA was useful for preoperative diagnosis of kissing aneurysms on distal ACAs.

Cognitive dysfunction and histological findings in rats with chronic-stage contusion and diffuse axonal injury

The Morris water maze (MWM) technique is well known as a prominent method of evaluating learning acquisition and memory retention impairments in rats. We previously reported on a modified fluid percussion device that is able to consistently produce experimental cortical contusion (CC) and diffuse axonal injury (DAI) in separate groups of rats. The purpose of the present protocol is to evaluate the differences in learning acquisition and memory retention impairments between these two types of injured rats in the chronic stage using the MWM technique. CC and DAI rats are respectively induced by lateral and midline fluid percussion. We also compare the histological differences between these two different types of traumatic brain injury. The results show statistically significant differences in learning acquisition impairment between the sham and CC rats and between the sham and DAI rats. However, a difference in memory retention impairment was expected to be seen only between the sham and DAI rats. Histologically, the loss of CA3 pyramidal cells in the hippocampus was observed ipsilaterally in the CC and bilaterally in DAI. Neuronal cell loss was observed in bilaterally in layer II of the entorhinal cortex in DAI, but not in CC.

Evaluation of learning and memory dysfunction and histological findings in rats with chronic stage contusion and diffuse axonal injury

We previously reported a modified fluid percussion device capable of consistently producing experimental cortical contusion (CC) and diffuse axonal injury (DAI) in separate groups of rats by lateral and midline fluid percussion, respectively. The purpose of the present study was to compare the differences in learning acquisition and memory retention impairments between these two types of injured rats in the chronic stage using the Morris water maze technique. We also compared the histological differences between these two different types of traumatic brain injury. The results showed a statistically significant difference in learning acquisition impairment between the sham and CC rats and also between the sham and DAI rats. However, a significant difference in memory retention impairment was observed only between the sham and DAI rats. Histologically, the neuronal cell loss of CA3 pyramidal cells in the hippocampus was observed on the ipsilateral side in the CC and bilaterally in DAI. The neuronal cell loss was seen in bilateral entorhinal cortex layer II in DAI, but it was not seen in CC. From these results, we speculate that the marked cell loss in the hippocampus CA3 region in both CC and DAI rats was related to the impairment of spatial learning acquisition. The marked cell loss in entorhinal cortex layer II in DAI rats may be one of the important factors in the impairment of spatial memory retention.

Marchiafava-Bignami disease: magnetic resonance imaging findings in corpus callosum and subcortical white matter

A case of Marchiafava-Bignami disease (MBD) is presented using magnetic resonance imaging (MRI). A patient with a long history of alcoholism developed a gait disturbance with involuntary movements at the lower extremities. MRI scans taken at the onset showed no particular abnormalities. He progressed to a coma 10 days later. MRI scans taken 20 days after the onset showed a focal lesion at the genu of the corpus callosum and he was diagnosed as having MBD. In addition, multiple lesions were observed in bilateral frontoparietal subcortical white matter. These lesions demonstrated similar intense MRI signals as the corpus callosum.

Skull Parosteal Lipoma with Reactive Hyperostosis: A Case Report

A 50-year-old female presented with more than 20-year history of a large subcutaneous mass in the left parieto-occipital portion. Magnetic resonance (MR) imaging revealed the lipomatous mass to show a high signal intensity in both T1- and T2-weighted images. A part of the lipomatous lesion progressed into the underlying hyperostosis and skull. The preoperative diagnosis was skull invasion of a well-differentiated liposarcoma. The tumor was removed completely, including the underlying hyperostosis and skull. Microscopy confirmed a lipoma without any lipoblasts, which was firmly attached to the reactive hyperostosis, and islands of lipoma were involved in the underlying hyperostosis and skull cortex. A pathological diagnosis of parosteal lipoma with reactive hyperostosis was made. Long-term progression of parosteal lipoma may cause to involve the underlying hyperostosis and skull, and led to the diagnosis of invasion of a malignant tumor on MR imaging.

Positron emission tomography findings in dysembryoplastic neuroepithelial tumor

Abstract Dysembryoplastic neuroepithelial tumor (DNT) has clinically and histologically unique characteristics. A precise preoperative diagnosis is difficult using magnetic resonance imaging (MRI) alone. A case of DNT that was examined using MRI and positron emission tomography (PET) to evaluate tumor cerebral blood flow (CBF) and metabolism is reported. MRI showed a remarkably hyperintense area on T2-weighted images in the right temporal lobe. A gyrus-like structure was seen in the right temporal lobe on both T1- and T2-weighted image. CBF PET showed hypoperfusion and a metabolic evaluation of PET using [ 18 F]–[ 10 B] fluoroboronophenylalanine (FBPA) showed a region of high uptake located within the low uptake tumor region. Histological studies confirmed a DNT. The heterogeneity of FBPA PET was thought to reflect the pleomorphic histological characteristics of DNT. A combined evaluation of MRI, tumor CBF PET and metabolic PET using FBPA is potentially very useful in preoperative differential diagnoses between DNT and low-grade gliomas.