The Measurement of Brainstem Blood Flow in the Experimental Recirculation Model of Brainstem Ischemia in the Rat

This report describes a surgical approach and measurement of brainstem blood flow (BBF) used in experimental ischemic model of the brainstem. The vertebral artery of Wistar rat was exposed and prepared embolic thread was inserted into the vertebral artery. The lesions of the baselar artery occuleded animals were restricted to the brainstem which, in the rat, is normally supplied by the vertebrobasilar artery. Using the hydrogen clearance techniques, blood flow of the brainstem was measured in 21 rats. The mean value of mean blood pressure (MBP) was 96.2±6.2 mmHg before ischemia. It dropped to 62.0±12.4 mmHg after transient hypertension. The preischemic BBF was 35.5±2.4 ml/100g/min. This was followed by a gradual increase to hyperperfusion after recirculation. After 1 hour of recirculation, BBF rose to a level above 78.9±5.9 ml/100g/min. These findings suggest that this model may be useful in the evaluation of pathophysiogical changes in brainstem ischemia

Diagnosis and Surgical Management of Foramen Magnum Meningioma

Two cases of foramen magnum meningioma were successfully treated at early stage. The magnetic resonance imaging (MRI) played an important role for accurate diagnosis. The tumors were microsurgically removed and the patuents returned to socity in full capacity. The foramen magnum meningioma is rare, and potentially curable. The recognition of this entity is important for neurologists, orthopodists and neurosurgenos in the differential diagnosis of the craniocervical problems

Measurement of Cerebral Cortical Blood Flow by Laser-Doppler Flowmetry in Rat Forebrain Ischemia

Laser-Doppler flowmetry　is a new method allowing convenient and continuous measurement of blood flow. The aim of our sutdy was to evaluate the accuracy of Laser-Doppler flowmetry for measurement of blood flow in the central nervous system, compared with the established hydrogen clearance method, especially under ischemic conditions. Ten male Wistar rats were subjected to 60 min of forebrain ischemia, induced by occlusion of the bilateral common carotid arteries and unilateral vertebral artery with systemic hypotension. Under these conditions, the cerebral cortical blood flow was measured, by both methods simultaneously, three times in each animal. The cerebral blood flows measured by the hydrogen clearance method and Laser-Doppler flowmetry showed linear relationship (r=0.89, p<0.01). Laser-Doppler flowmetry facilitates accurate measurement of relative cerebral cortical blood flow under ischemic conditions

Aneurysm Arising from the Junction of Internal Carotid Artery and Duplicated Middle Cerebral Artery

A case of an aneurysm arising from the junction of the internal carotid artery and duplicated middle cerebral artery was reported. A 77-year-old female was admitted to our hospital with complaints of headache, nausea, vomiting and disturbance of consciousness. CT scan showed a high-density area in the basal cistern and Sylvian fissure. Carotid angiography revealed saccular aneurysm arising from the junction of the right internal carotid artery and duplicated middle cerebral artery orginating from the internal carotid artery. The neck of aneurysm was clipped via the basal interhemispheric approach on the day of onset. Transient right oculomotor nerve palsy occurred in the postperative course. Normal pressure hydrocephalus was treated by ventriculoperitoneal shunt. The relationship between the genesis of aneurysms and the duplicated middle cerebral artery was discussed. From the location of these aneurysms associated with the duplicated middle cerebral artery, we suggested that congenital etiological factors were modified by the acquired hemodynamic factors