Masahiro Mizukami

Prevention of Vasospasm by Early Operation with Removal of Subarachnoid Blood

Sixty-four patients who were operated on within 4 days after acute subarachnoid hemorrhage are included in this study. All patients underwent preoperative computed tomographic (CT) scanning, and the amount and distribution of subarachnoid blood clot were noted. Operation was carried out by the frontobasal lateral approach, and the subarachnoid clot was removed by microsurgical suction-irrigation after clipping of the aneurysm. Immediate postoperative CT scanning was performed to evaluate the completeness of the subarachnoid blood clot removal. The presence or absence of postoperative vasospasm was determined with angiography performed between the 7th and 10th postoperative days. All patients were, of course, also evaluated for evidence of neurological deterioration. Approximately two-thirds of the patients in this series showed high density subarachnoid blood clot on the preoperative CT scan. The postoperative CT scans showed that it was possible to remove the majority of the blood clot except that located in the frontal interhemispheric fissure, the posterior part of the insular cistern on the approached side, and all of the insular cistern on the contralateral side. There was no spasm or only mild spasm in any site where the blood clot had been successfully removed. Delayed neurological deficits occurred only in those cases in which subarachnoid blood clot remained in the cisterns. These results suggest that it is possible to prevent intracranial arterial spasm and associated neurological deterioration by early operation and removal of clotted blood from the subarachnoid space.

Value of computed tomography in the prediction of cerebral vasospasm after aneurysm rupture.

The relationship between high density (HD) on computed tomographic (CT) scans (which indicates a collection of blood in the subarachnoid space) and cerebral vasospasm was studied in 177 patients with ruptured aneurysm. The development of cerebral vasospasm was confirmed at the high rate of 84.6% in 26 cases where HD was demonstrated on the CT scan within 4 days after subarachnoid hemorrhage (SAH). In 8 cases where HD was not found on the CT scan obtained within 4 days after SAH, no cerebral vasospasm was seen. However, no relationship was found between HD and the occurrence of cerebral vasospasm in cases in which CT was performed after the 5th day of disease. It is suggested that CT performed within 4 days after SAH may give important information for predicting cerebral vasospasm.

Topographic Electroencephalographic Study of Cerebral Infarction Using Computed Mapping of the EEG

Computed mapping of the electroencephalogram (CME) is a newly developed method using a microcomputer system that displays the scalp topograph as the square roots of the average power spectra over each EEG frequency band on a color television screen. This new device has been employed in an examination of functional lesions in 20 patients with aphasia due to cerebral infarction. The results were compared with those of computed tomography (CT) and regional cerebral blood flow (rCBF) studies using intracarotid 133Xe. A high-voltage focus of slow components and an asymmetrical distribution of alpha activity were regarded as signs of functional lesions on CME. Twelve patients showed high-voltage foci and six showed asymmetrical alpha activity on CME, which correlated well with the lesions on CT and/or rCBF studies. Especially in patients with motor aphasia, CME demonstrated the abnormality in advance of the appearance of a low-density area on CT. Compared with conventional EEG interpretation, CME is very useful in topographic and objective diagnosis of functional lesions, although the source of the data is the same as for the conventional EEG.

Is angiographic spasm real spasm

SummarySystematic morphological study of the cerebral arteries was made in six autopsy cases of ruptured aneurysms. The time course of the arterial luminal narrowing was observed by repeated angiograms, and segments of the narrowed arteries were studied histologically.Various histological changes were found consistent with the angiographic findings. We have devided these into three stages according to the duration of the disease.In the acute stage (less than one day) the contraction of the medial smooth muscle cells may be the main cause of the luminal narrowing. In the subacute stage, arteries showed a reduction in lumen size with medial thickening, marked corrugation of the internal elastic lamina, and thrombus formation attached to the endothelial surface. If vasoconstriction remained localized to the same segment for several days, the intimai or medial thickening and thrombus might produce the luminal narrowing consistent with the angiographic narrowing. In the chronic stage (more than two weeks), most cases showed dilatation of the arterial lumen on angiography. These arteries showed frank necrosis of the smooth muscle cells histologically. In a case which demonstrated progressive luminal narrowing on angiograms over 2 weeks, the arterial wall showed luminal narrowing with cellulofibrous thickening of the intima and organization of the thrombus.The presence of these structural changes in the narrowed arteries seen at angiography seems to be very important for proper understanding and treatment of vasospasm.

Topographic electroencephalographic study of transient ischemic attacks

Twenty-five patients with TIAs in the carotid artery distribution were studied by means of computed mapping of EEG (CME) and conventional EEG. In addition, CT scan and cerebral angiography, and in 10 patients rCBF measurements were performed. The CME provided topographic maps of the average power spectra for each of 6 frequency bands from 2.0 to 29.5 Hz which were displayed two-dimensionally in a color-coded isopower format. EEG abnormalities were analyzed and the results of the two different methods of EEG interpretation were compared. Sixty-eight percent of the patients showed unilateral abnormalities on CME appropriately lateralized to the clinical symptoms even after these symptoms had cleared completely. Furthermore, 88% of those who were examined within 2 weeks of last TIA showed corresponding CME abnormalities. Only 3 out of 10 TIA patients who had rCBF studies showed reduction of blood flow on the appropriate hemisphere, whereas 7 of the 10 patients had corresponding CME abnormalities. Comparing the results of the CME and of conventional EEG reading revealed the CME to be slightly more sensitive in detecting asymmetrical voltage depression of background activity than the conventional reading of the EEG, while the latter detected low amplitude sporadic activities which were missed by CME. Both methods were equally sensitive in detecting slow wave foci and non-transient symmetrical changes. The two most significant points of this report are the following: first, 68% of the TIA patients studied had residual unilateral abnormalities in CME in their symptom-free period. In the subset of patients subjected to rCBF studies only 30% showed residual flow aberrations, whereas 70% of the same subset demonstrated unilateral abnormalities in CME. Second, though conventional EEG reading by an experienced electroencephalographer can nearly match the performance of CME the CME format makes subtle but useful EEG findings readily available to the uninitiated. The CME also quantifies the data making objective comparisons more amenable to software manipulations for further studies.

Arteriographically Visualized Extravasation in Hypertensive Intracerebral Hemorrhage

Seven cases are reported in which extravasation of contrast medium from the lateral lenticulostriate artery was observed on cerebral angiography performed in the early stage of hypertensive intracerebral hemorrhage. We advance the theory that continuous bleeding from the ruptured artery with mechanical destruction and displacement of cerebral tissue is the cause of massive hematoma formation, and discuss the possibility of surgical treatment of the acute stage of hypertensive intracerebral hemorrhage.

CT and arteriographic comparison of patients with transient ischemic attacks--correlation with small infarction of basal ganglia.

Fifty patients presenting clinically with TIAs were examined angiographically. Twenty one patients (42%) had no abnormality. Twenty patients (40%) had stenosis or occlusion in the MCA, ACA or intracranial carotid, whereas 11 (22%) had involvement of their extracranial internal carotid artery. Seven of the 28 CTs performed showed basal ganglia infarcts. This suggests that the cause for the TIA was an infarct in the vascular territory of a lenticulostriate artery.

Computed tomographic findings of good prognosis for hemiplegia in hypertensive putaminal hemorrhage.

Computed tomography (CT) findings were analyzed in 17 patients with hypertensive putaminal hemorrhage accompanied by hemiplegia which had subsided almost completely by conservative therapy within one month after the onset. In such patients a high density area was not seen at the level of the lateral ventricles on CT scan. To study the reason for this, the relationship between the extent of a hematoma and the level at which the pyramidal tract was destroyed was investigated. From consideration of the process of destruction of the pyramidal tract by a hematoma, it seemed that CT findings at the level of the bodies of the lateral ventricles, rather than at the level of the posterior limb of the internal capsule, were of value in evaluating the prognosis of hemiplegia in putaminal hemorrhage.

Topographic Electroencephalographic Study of Ischemic Cerebrovascular Disease

Publisher Summary Presence of the slow wave components and slowing, or amplitude depression of background activity on the ischemic side suggest a relationship between cerebral ischemia and the resulting electroencephalographic abnormalities. Polymorphic delta activity and an asymmetrical distribution of background activity are thought to be unilateral signs of the EEG abnormalities in ischemic cerebrovascular disease. The incidences of the resulting EEG abnormalities have differed widely in various studies; these unilateral EEG abnormalities are found in 67.6% of the patients with unilateral cerebral infarction, in 85.7% of those with occlusive cerebrovascular disease, and in 90.3% who had an infarct in the carotid or middle cerebral arterial territory. These variations in the results are considered to depend on some basic factors. The three important factors influencing the resulting EEG abnormalities in cerebral ischemia are as follows: (1) localization of the ischemia area, (2) the duration of the ischemia, and (3) the interval between the onset of ischemia and the recording of the EEG.

Intraoperative use of real time ultrasonography applied to aneurysm surgery.

The intraoperative application of real time ultrasonography during 13 neurosurgical operations for intracranial aneurysms is reported. In 2 cases, the aneurysms themselves could be detected clearly by real time ultrasonic imaging. In the case of a large aneurysm, information about the nature of the aneurysmal wall was obtained. Other lesions coexisting with the aneurysm (namely, intracerebral hematoma, massive subarachnoid hemorrhage, and hydrocephalus) could be recognized clearly. Real time intraoperative ultrasonography is considered to be useful in aneurysm surgery.