Minoru Kidooka

Dissecting aneurysm of the anterior cerebral artery: Report of two cases

Two cases of spontaneous dissecting aneurysm localized to the anterior cerebral artery are reported. Both patients experienced severe headaches, followed by symptoms of cerebral ischemia. In the first case, the dissecting aneurysm showed an angiographic appearance resembling a saccular aneurysm of the anterior communicating artery, and the diagnosis of dissecting aneurysm was confirmed at operation. The second case was treated conservatively, and the diagnosis was reached by repeat angiographic studies.

Monitoring of somatosensory-evoked potentials during aneurysm surgery

Somatosensory-evoked potentials were recorded during and after 31 operations for intracranial aneurysms, and the changes in the central conduction times, namely, the interpeak latencies between the N14 and N20 peaks in response to bipolar stimulation of the median nerve, were studied. Neuroleptanalgesia and routine intracranial operative procedures such as opening the dura mater, drainage of the cerebrospinal fluid, gentle retraction of the brain, and microsurgical dissection of the circle of Willis, were found to have no significant adverse effect on the evoked responses, whereas the temporary clipping of the major cerebral artery or premature rupture of the aneurysm associated with hypotension or both, often caused significant prolongation of the central conduction time. Prolongation of the central conduction time exceeding 1.2 ms or disappearance of the N20 peak adversely affected the postoperative conditions in 8 of 13 patients (62%).

Anaplastic ganglioglioma with dissemination to the spinal cord : a case report

BACKGROUND Gangliogliomas are rare tumors that generally arise in the temporal lobe. Although most are benign, malignant gangliogliomas have been reported. The clinical course of anaplastic gangliogliomas has not been well understood. CASE REPORT An anaplastic ganglioglioma of the right parieto-occipital lobe is reported in a 7-year-old girl who presented with left homonymous hemianopsia and papilledema. Neurologic examination revealed a choked disc and a left homonymous hemianopsia. A computed tomographic scan and magnetic resonance imaging showed a large enhancing mass with calcification. Radiation therapy was administered after subtotal resection of the tumor. Histologic and immunohistochemical studies showed a typical appearance of anaplastic ganglioglioma. Spinal dissemination developed 3 months after the operation. In spite of spinal axis radiation and chemotherapy, she expired 15 months after the diagnosis. CONCLUSION Although the clinical course of anaplastic gangliogliomas is not always aggressive, our case indicates the importance of strict follow-up assessments of the whole craniospinal axis.

Association between accessory middle artery and cerebral aneurysm: Report of two cases

SummaryTwo cases of accessory middle cerebral arteries associated with cerebral aneurysms are reported, and the literature concerning this rare association is reviewed.

Postoperative Sella: Evaluation with Fast Spin Echo T2-weighted High-resolution Imaging

OBJECTIVE The purpose of this study was to investigate the magnetic resonance features of the postoperative sella with fast spin echo (FSE) T2-weighted high-resolution imaging and to evaluate the benefits of the sequence using a follow-up magnetic resonance imaging protocol after transsphenoidal surgery. METHODS Coronal spin echo (SE) T1-weighted and FSE T2-weighted images were prospectively obtained in 24 patients after surgery for pituitary adenomas. We observed the signals and the contour of normal structures, fluid collection, implanted materials, and mass lesions, including granulation tissue and adenoma. RESULTS The pituitary gland was delineated in 51 of 59 FSE T2-weighted images, 90.2% of which presented clear boundaries. Whereas the gland was detected in 49 of 58 SE T1-weighted images, only 20.4% showed the boundaries. A mass lesion was identified in each of 12 patients with good resolution on FSE T2-weighted images. SE T1-weighted images detected mass lesions in 7 of 12 patients without distinctive boundaries. Contrast enhancement had little advantage in clarifying the boundaries between normal and abnormal structures. For the detection of mass lesions in the sella, the kappa values for interobserver agreement were 0.8 for FSE T2-weighted images and 0.25 for SE T1-weighted images. CONCLUSION FSE T2-weighted imaging is a reliable method with which to assess the sella with sufficient resolution after transsphenoidal surgery. The combination of unenhanced SE T1-weighted and FSE T2-weighted images may reduce the use of contrast material after pituitary surgery.

Effect of calcium antagonist and agonist on free fatty acid liberation in the ischemic brain of rats

Using an experimental model of global ischemia of the brain in rats, we have shown that a Ca2+ antagonist nicardipine attenuates, and a Ca2+ agonist YC-170 accelerates, the liberation of free fatty acids in the ischemic whole brain. The effects of YC-170 were negated by the previous administration of an adequate dose of nicardipine. This is the first report on the action of a Ca2+ agonist on the metabolism of the brain, and the results seem to provide supportive evidence for the role of Ca2+ in ischemic injury of the brain.

Ca2+ antagonist and protection of the brain against ischemia. Effects of nicardipine on free fatty acid liberation in the ischemic brain in rats

Using a model of global cerebral ischemia in rats, we examined the effects of a dihydropyridine Ca2+ antagonist, nicardipine, on the liberation of free fatty acids (FFAs). After decapitation of the animals, FFAs showed a rapid progressive increase for a whole experimental period of up to 60 minutes without reaching a plateau. Nicardipine in a dosage of 1 mg/kg effectively attenuated the liberation of FFAs, particularly that of arachidonic acid which is known as the precursor of prostaglandins, thromboxanes, and leukotrienes. The FFAs of the brain have been known as one of the biochemical markers that indicate ischemic damage of the brain cell membrane. The results of the present study support a possible protective effect of Ca2+ antagonist against cerebral ischemia.

Transient spontaneous regression of mass effect with glioma.

SummaryA spontaneous regression of the lesion seen in sequential computertomographic scans does not necessarily indicate a nonneoplastic nature of the pathological process. Two patients with pathologically verified glioma of the brain which showed a temporary regression of the mass effect are reported, and the mechanism of the regression of computertomographic mass signs is discussed.

Transient cerebral ischemia evoked by yawning: An experience after superficial temporal artery-middle cerebral artery bypass operation

Abstract A patient with recurrent cerebral ischemia induced by yawning is reported. The patient had undergone a superficial temporal-middle cerebral bypass operation previously, and the cause of the cerebral ischemia was found to be a kink in the donor artery by an action of opening the mouth widely.

Cerebrospinal fluid entrapment cysts with subarachnoid dissemination of medulloblastoma: CT findings

We report an unusual case of meningeal dissemination of medulloblastoma in which multiple cerebrospinal fluid entrapment cysts developed within the cerebral fissures and cisterns. The condition was first diagnosed by CT. Cysts reduced in size following radiotherapy.