Twenty five cases of watershed infarction were found on CT among 362 patients with cerebral infarction (7%). CT findings, contrast enhancement, angiography and clinical course of these patients were reviewed and results were as follows;
(1) In 23 cases, lesions were found at watershed area of anterior cerebral artery and middle cerebral artery, in which 3 showed bilateral low density zone. Lesions in middle cerebral-posterior cerebral borderzone were identified in 4 patients.
(2) On angiography, occlusion or stenosis of internal carotid artery were the most common findings (86%), including 2 cases of spontaneous occlusion of circle of Willis (so-called Moya Moya disease).
(3) Eleven had bilateral lesions, and hypoplastic proximal anterior cerebral artery (A₁portion) were frequently observed in both unilateral and bilateral cases. These findings indicate that the circulatory disturbance of contralateral side will be the important factor for the appearance of watershed infarction in addition to the ipsilateral circulatory disturbance.
(4) Intrathalamic low density zone was found in 3 cases and was considered as an atypical type of watershed infarction.
(5) Contrast enhancement and follow up CT were useful for the detection of watershed infarction.
We conclude that watershed infarction on CT is the reliable sign of decreased cerebral blood flow and suggest the occlusion or stenosis of internal carotid artery with insufficient collateral circulation. Therefore, angiography should be followed and indication of bypass operation should be taken into consideration in such cases.

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The CT of acute (within a week) severe cerebral infarctions was analyzed in comparing with pathological findings of our experimental cerebral infarctions in dogs. The results obtained were as follows:
1. The CT fell into two categories. The first type represented that contrast enhancement was positive at the border zone of the cortical gray and subcortical white matters in the ischemic area. The second type showed contrast enhancement which did not limit within the border zone but occurred throughout the entire cortical parenchyma in the ischemic area.
2. The dogs in which the middle cerebral artery (MCA) was clipped unilaterally, were devided into two groups. The first group represented animals which were kept MCA clipped for 24 hours and at that time carbon particles were perfused...permanent occlusive models. The second group was that in which MCA clip was removed 4 hours after, then involved area was recirculated for 20 hours and carbon particles were perfused...recanalized models. In permanent occlusive models, carbon particles extravasated only into the border zone of the gray and white junction, while in recanalized models, carbon particles strongly extravasated both in the gray and white junction and in all cortical layers.
3. An extravasated area of the permanent occlusive models were well corresponded to an enhanced area of CT in the first type and the recanalized models were also corresponded to the second type. The second type showed a poor prognosis which might be attributable, at least in parts, to frequent occurrences of the hemorrhagic infarctions.

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Formarly patients of stroke received treatments at their home, because it is generally said that those people who had a stroke had to take absolute rest. But recently these patients have come to have the need of medical cares for respiratory distress and the surgical treatment for the stroke has been surprisingly improved, so the number of stroke patients who are sent to the hospital is gradually increasing.
According to our investigation the number of inpatients of stroke has increased 0.8%to 2.2%these ten years and the ratio of cerebral hemorrhage and cerebral ischemic disease among them has become less. In 1969 the ratio of these patients is 32:18 and in 1979, 34:94.
Until the introduction of the computerized tomography (CT), stroke has been diagnosed by clinical symptoms, signs and several diagnostic procedures, for example, carotid angiography and brain scintigraphy. Utilizing CT, the most accurate anatomical localization and definition of the pathological sequelae to occlusive or hemorrhagic disorder are obtained. Among our recent 100 cases who have been diagnosed as cerebral infarction and examined with CT, 64 have been decided in less than 4 weeks after the disease was taken. Lately the infarct cases have been subdivided into two groups; the first consisted of those which were examined in less than 7 days after the disease was taken, the second, the infarct dated back 8 to 28 days before the examination.

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Two cases of acute basilar artery occlusion, a 63-year-old male case and a 71-year-old female case were presented. The diagnosis of basilar artery occlusion was made by means of cerebral angiography and autopsy. The CT appearance within 24 hours after onset was an ill-defined decreased density of white matter of the occipital lobe and the cerebellum. The CT appearance beyond 24 hours after onset was a well-defined decreased density of the cerebellum and the occipital lobes, which was supplied by posterior cerebral arteries. Pontine lesion was not remarkable on the CT-image in our cases. Gross autopsy findings showed no remarkable lesion in the cerebellum and the occipital lobe in Case 2, who died 7 days after onset. Histologically, however, definite brain edema detected in these brain regions.

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Determination of angiographic indication for carotid endarterectomy (CEA) requires a precise estimation of degree of stenosis or presence of ulceration. The authors have proposed a new angiographic method and utilized it for diagnosis of pathologies at the cervical carotid bifurcation since 1974. The method consists of measurements of a relative luminal diameter of the carotid lumen to a diameter of the common carotid artery (A value). The measurements were taken at 6 standard points which were determined by a distance (decided by the A value) from the bifurcation.
The present study was undertaken to compare the angiographic diagnosis by our method with actual measurements of the tissue removed during CEA. Fifteen specimens, removed without extensive damage to the tissue, were chosen for this study and included 7 stenotic and 8 ulcerated plaques.
Results of comparative measurements indicated that the degree of stenosis, actually measured, was always larger than that measured angiographically. The difference was most pronounced (16% average) in stenotic lesions of a circular type, involving all around of the vessel wall, than that of a semi-circular leison, located in the posterior wall of the bifurcation. The angiographic diagnosis of ulcerated plaque correlated well to the macro and micro scopic findings of the specimen, except in the microulcer at the steep plaque. Some of the microulcers appeared to have a complete covering of regenerated endothelial cell sin scan electron microscopic observation.
The authors proposed to add 20% to the angiographic stenotic degree for the circular type stenosis and a careful angiography from multiple directions is needed for diagnosis of an unhealed microulcer at the steep Plaque.

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The purpose of this report is to analyse the relationship between the stenosis of the carotid bifurcation and the location of infarction in patients with stroke. CT scans of 22 patients with the stenosis of the carotid bifurcation were examined out of 204 cases of acute stroke.
In 8 patients with single stenosis of the carotid bifurcation, 7 (88%) had small infaction of basal ganglia on CT scan. Three of them showed enhancement by contrast medium.
In 14 patients with tandem stenotic lesions of the extracranial and intracranial arteries, 7 (50%) showed also small low density areas of basal ganglia. Cortical infaction was found in only one case which had severe stenosis of middle cerebral artery.
In these patients with the small low density of basal ganglia, the pathogenesis of infarction is suspected to be occlusive or stenotic lesions of the perforating arteries.
The stenosis of the carotid bifurcation is supposed to be incidental lesion in these cases.

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The clinical features of ischemic cerebrovascular diseases differ largely depending on the degree of collaterals or on the site of arterial occlusion. Following lots of neurosurgical therapeutic trials in ischemic cerebrovascular diseases, it has been said that the indication of sugical anastomosis is such stroke patients as suffering from minor stroke like TIA or RIND. In order to assess the reasonability of surgical intervention in patients having minor stroke and major cerebral artery occlusion, the non-surgical course of 34 patients having internal carotid artery or middle cerebral arterial trunk occlusion were observed. They all were judged as minor stroke, who had neither remarkable consciousness disturbance, complete hemiplegia, nor severe visceral complication. In the present follow-up study, attention was focused in two points; (1) the incidence of clinical deterioration either because of reattack or newly developed completed stroke, (2) the alteration of development of completed stroke. Consequently, 9 cases (26%) developed completed stroke within a month, 6 cases (18%) repeated minor stroke, 10 cases (30%) developed severe visceral complication in the follow-up intervals (mean 17.5 months). Cases with atrial fibrillation showed the development of completed stroke more frequentry than those without. In addition, cerebral angiographies repeatedly done at the deterioration stage apparently showed alteranative findings compared with those at the onset. They can be divided into two categories; recanalization of the occluded artery and the progres-sion of occlusion on the blood passage through collateral. These data can afford several informations as for the indication of the reconstructive surgery in patients having occlusive cerebrovascular diseases from major cerebral artery occlusion. We assume that especially cases with atrial fibrillation must be considered their protection against the development of completed stroke even when their neurological deficits are judged as minor, and that sugical intervention might be indicated for this purpose.

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The previous studies have shown that the reduction of cerebral blood flow (CBF) is seen in patients with stenotic lesions of the cervical carotid artery exceeding 70% or more. However, these reports have not mentioned on the reduction of CBF in patients with ulcerated plaques. The purpose of this study is to investigate changes in CBF associated with occlusive lesions at the cervical carotid artery including the ulcerated plaques. Regional CBFs were determined from clearance-curves obtained from the extracranial detection of intraarterially or intravenously injected ¹³³Xenon. Results were divided in two: localized and generalized (mean CBF) abnormalities.
Five cases with the carotid stenosis (mild stenosis 2, mild stenosis+ulcer 2, severe stenosis+ulcer 1) and 6 cases with the complete carotid occlusions (including bilateral carotid occlusion 1, contralateral carotid stenosis 2) were studied. The result of CBF measurement showed abnormalities in all cases. The mean CBF was abnormally low in 8 cases and the CBF was reduced locally in 7 cases. In three of 5 cases with mild stenosis (including 2 cases of mild stenosis with ulcer), a significant local reduction was noted. In remaining two, the reduction was general, but the reduction was thought to be due to additional intracranial arterial lesions (stenosis at the siphon and recanalized MCA stenosis respectively). In 5 of 6 cases with the complete carotid occlusion, the general reduction of CBF was observed.
Thus, CBF change, either localized or generalized, might be related to the cause of ischemic cerebrovascular disease, because pure ulcerations without stenosis of high degree would produce localized reduction of CBF, if it occurs. The measurements of CBF are of value in determining a surgical indication, especially in patients with multiple extra and intracranial arterial lesions.

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Brain scintigraphy was performed using ^99mTc-Albumin Microspheres (^99mTc-AMS) for study of microcirculation of cerebral ischemic lesions.^99mTc-AMS was injected into carotid arteries and/or vertebral arteries respectively, and brain scintigram was obtained with routine method.
^99mTc-AMS scintigraphy was performed 54 times for 30 patients with cerebrovascular ischemic disease. Complications due to injection of ^99mTc-AMS were not seen except only one patient who developed transient motor dysphasia.
Patent vascular beds corresponding to the particle sizes of AMS were visualized on ^99mTc-AMS scintigrams and therefore, ischemic area was clearly revealed.
“Functional”watershed area was visualized on the colour displayed ^99mTc-AMS scintigrams as an overlapped area, and it shifted following the changes of cerebral hemodynamics (collateral circulations). Cortical ischemic lesions are seemed to be developed at these functional watershed areas if perfusion pressure is insufficiently low. So, in cortical ischemic lesions detected by these scintigrams, there seemed to have an indication of surgical revascularization at the favourable phase.
In some cases, the collapse of microvasculature and/or the presence of arteriovenous shunts were demonstrated by the findings of ^99mTc-AMS scintigrams using different sizes of microspheres. For these cases with completely obstructed changes of cerebral microvasculature, there seems to have no indication for surgical revascularization.
^99mTc-AMS scintigram is thought to be very useful for the recognition of cerebral microcirculation especially at the ischemic lesions in situ.

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The patency of the STA-MCA anastomosis for eleven cases were studied by vascular imaging with ^99mTc labelled autologous red blood cells. Four cases out of these eleven patients were also studied by brain scintigram with Tc-99m pertechnetate. For vascular imaging, the kit for the preparation of^99mTc labelled red blood cells (Ref. TCK-11, CIS) was used. Radionuclide cerebral angiography and the static image of the head (4 views) and neck (3 views) were obtained after intravenous injection of radionuclide (^99mTc-RBCs and/or Tc-99m pertechnetate). The patency of STA-MCA anastomosis was clearly visible on ^99mTc-RBCs angiography in eight out of the eleven cases and positive image of anastomosis was visible on^99mTc-RBCs static vascular image in six cases.
But, the patency was visible on ^99mTc pertechnetate radionuclide angiography in two out of four patients. The patency of anastomosis at the temporal region was more clearly visible on ^99mTc-RBCs radionuclide angiography than Tc-99m pertechnetate angiography. The ^99mTc-RBCs vascular imaging is valuable for the detection of the patency of STA-MCA anastomosis.

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Hemodynamics in ST-MCA were investigated transcutaneously by bidirectional ultrasonic Doppler flowmeter with sound spectrograph on 20 bypasses of 17 patients, including 6 with “moyamoya” disease and one with internal carotid giant aneurysm. These bypasses were performed in 15 for occlusive lesions of the middle cerebral artery and/or the internal carotid artery on the side of ST-MCA and in 5 for stenotic lesions of them. Flow measurements were performed preoperatively and postoperatively in arteries being closely related with ST-MCA (common carotid arteries, internal carotid arteries, external carotid arteries, superficial temporal arteries, and ophthalmic arteries). Preoperative findings of Doppler flowmetry were in good agreement with those of preoperative angiography. In postoperative flow study, flow through the donor artery was poor or not detected in five ST-MCAs and four of them were in patients with “moyamoya” disease and one in patient with internal caritid stenotic lesion. In the remaining 15 good-functioning bypasses (75%), flow pattern of the superficial temporal artery, which was naturally the flow pattern of the external carotid artery, turned to that of the internal carotid artery. These results were also in good agreement with the findings of postoperative angiography. Relatively poor function in those with “moyamoya” disease accompanied with a relatively well developed collateral circulation and in those with stenotic lesions was ascribed to the low pressure gradient between the donor and recipient artery. Flow study by Doppler ultrasonic flowmeter with sound spectrograph was very useful not only to know the graft patency of ST-MCA but also to obtain various kinds of hemodynamic information on ST-MCA.

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The method utilizing the Doppler effect of ultra sound has been applied to the screening of the obstruction or narrowing of internal carotid and middle cerebral arteries. When the Doppler sound is processed by frequency analysis to give power spectrogram, the acoustic characteristic of the hemodynamics may be clearly indicated by the spectrogram.
The patients subjected to this study consisted of 6 internal carotid arterial obstruction, 7 cases of the narrowing of internal carotid artery, 14 cases of the obstruction or narrowing of middle cerebral artery, 15 cases with the elongation of internal carotid artery or arteriosclerosis, and 10 cases from which the Doppler sound was recorded directly from intracranial internal carotid artery at the time of operation. The Doppler sound recording from other patients was made from common carotid artery, superficial temporal artery and supraorbital artery. The doppler sound recorded were analyzed a data processer ATAC-450, and resultant power spectrograms were compared with corresponding angiograms in order to examine the usefulness of the power spectrogram.
The normal pattern of the spectrogram obtained from common carotid artery consisted of frequency components which distributed from low frequency range to high frequency range. The maximum energy was found at the frequency of 670±99 Hz. Thus the spectrogram was in the shape of an one peak hill. The power of this maximum energy was reduced and the peak frequency was also shifted to the frequency range lower than 500 Hz, when there existed the narrowing or obstruction of internal carotid artery, namely, the peak value became 441±97 Hz for the narrowing and 364±78 Hz for the obstruction, and the overall shape of the spectrogram changed to a steep hill type. In the cases of middle cerebral arterial obstruction and narrowing, the peak appeared at 360±72 Hz and the spectrogram did not show the hill shape with a single peak.
It is concluded that the power spectrogram of Doppler ultra sound is a useful non invasive method for the diagnosis and screening of obstructive cerebrovascular diseases.

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Readiness potential is a slow negative shift of brain electrical potential preceding voluntary movements. The amplitude of the potential is of its maximum over the area of the contralateral motor cortex which represents contraction of muscles. But this is distributed in rather diffuse fashion and can also be obtained in bilateral regions. The potential is obtained by averaging the EEG synchronized with the repetitive movements.
Readiness potentials were recorded in the central scalp region in two groups; Group 1 as control consisting of six healthy right-handed persons, and Group 2 of seventeen patients with occlusive cerebro-vascular diseases who had varying degrees of motor weakness and underwent the superficial temporal artery-middle cerebral artery anastomosis. The potentials in Group 2 were obtained by carrying out voluntary movements on the unaffected side. A relationship between the preoperative readiness potentials and the surgical results was discussed.
1. In control group, hand movements elicited the potential (N) with the amplitude being 7.7±0.8 μV (mean±standard error of means) on the ipsilateral side to movement and 8.9±1.0 μV on the opposite side.
2. In group 2, N was 3.2±0.1 μV on the side of the hand movements and 5.4±0.8 μV on the opposite side.
3. Four patients with normal amplitude (more than 5 μV) on the scalp of the lesioned side showed good results from surgery. On the other hand, four patients with very low amplitude (less than 2μV) had poor results.

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Somatosensory evoked potentials (SEP) and power spectrums of EEG were examined on 27 patients of cerebrovascular diseases. Observation of cerebral blood flow (CBF) was also made in 4 patients.
Patients were divided into 2 major groups by findings of computed tomography. Group (I) was cases with deep lesion of the thalamus and/or internal capsule, Group (II) was those with superficial lesion of the cortical and subcortical regions. Each group was further divided into two subgroups,“bleeding” and “infarction”. EEG power spectrum analysis was done with ATAC 2300 computer. The ratio of 2-6 Hz slow wave power to total power was expressed as Slow Wave Index (SWI).
SEP was evoked by the median nerve stimulation of 0.5 and 2.0 Hz respectively. A deterioration of SEP was more marked in group (I), whereas a SWI was tended to be larger in group (II). In both group (I) and (II), changes in SEP was more remarkable in bleeding cases.
Increase of slow wave power accompanied with a tendency to reduction of amplitude in N₁ and N₂ of the affected side. However, there were no definite correlation between SWI and latency of all components in SEP.
In control, an amplitude of N₁ and N₂ became large by 2 Hz stimulation as compared that evoked by 0.5 Hz. On the contrary, the amplitude reduced in affected side of group (I) by 2 Hz stimulation.
In many cases of group (I), non-affected side also showed a decrease in CBF and an increase of SWI. In those cases, however, SEP did not show any remarkable changes. No correlation was noted between SWI and amplitude of SEP in non-affected side.

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17 patients with completed stroke were the participants of this study. They were all alike in that they underwent STA-MCA anastomosis sometime in the course of the disease and that they received serial CT scans both pre- and post operatively. Preoperative scans were performed not before seven days of surgery and one taken in the acute stage was always included. Both plain scan and contrast enhancement study were done in each occasion. The result of the surgery was estimated within a week after surgery.
By comparing the findings of serial scans with the result of the surgery, the authors tried to seek any important correlation between the two.
Significant observations from the study are as follow: First of all, the authors estimated the result of the surgery as improved in 9 out of 17 cases and at the same time found 7 out of those nine coming from the group of patients who showed either normal finding or low density area. Second of all, these findings did not change during pre- and postoperative serial scans. Third of all, in 8 cases whose result of the surgery was estimated either as no effect (6 cases) or as worse (2 cases) came from the group whose preoperative CT scans showed either positive contrast enhancement or mass effect beside low density. Fourth of all, postoperative contrast enhancement became greater in degree (5 of 6 cases) or even grew up to the one of hemorrhagic infarction (4 of 6 cases). Mass effect also enlarged in one out of two cases.
From the above, the authors conclude that serial CT scans are true aids to make STA-MCA anastomosis surgery rational in terms of indication, period and favorable result.

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To determine the indication of the by-pass operation for the stroke, we focussed on the cases showing High Density (H. D.) area in the postcontrast CT scans of the cerebral infarction. (the H. D. area was named as Ribbon H. D.). 38 cases of the Ribbon H. D. in the cerebral infarctions were verified concerning to the time of appearance of the H. D. area, features of its location and nature and its histological findings.
The Summary was as follows;
1. Ribbon H. D. reaches its peak in the latter half of the 2nd week after onset, and then gradually decreases.
2. Ribbon H. D. often appears along the cortical ribbon, and does not show massive shadow in the deep zone.
3. Ribbon H. D. is due to the transudation of contrast media, and does not always indicate hemorrhagic infarction.
4. Ribbon H. D. shows the incomplete necrosis, and in its nearby region we always find the slight lesions of only gliosis.
According to 1st, 2nd 3rd points of the summary, we considered,“It is not so dangerous that we perform the operation of STA-MCA anastomosis to the cases of Ribbon H. D. in the early stage.”
According to 4th point of the summary, we should rather perform the operation of STA-MCA anastomosis as early as possible. Aad then, according to this idea, anastomosis was actually done.
Result; But, we cannot find any correlation between the effect and the time of surgery.
Because, there is a difference of 20 years or more in average age between a group of Grade 1 (fully indipendent) and a group of Grade II (Handicapped) and III (disabled).
Our conclusion; Accordingly, at the present time, when the indication to TIA and RIND is accepted, to stroke, there is no alternative method but to select a logically good time and good case.

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Extrcranial-Intracranial (EC-IC) bypass surgery is now an established procedure as a treatment for ischemic strokes. However, there have been some controversies over the efficacy of this surgery for patients with completed stroke.
One of the problems is difficulty to select proper candidates.
The authors have found that the Hyperbaric Oxygenation (HO) is a useful technique to determine candidates for bypass surgery.
Twelve patients with completed strokes underwent HO for 70 min. per day. Neurological conditions and EEG were evaluated after twenty times of HO.
Nine patients showed significant improvement and were considered as responders to HO. Three patients were non-responders.
EC-IC bypass was performed for all of these patients.
Five out of nine responders to HO showed consistent improvement after STA-MCA anastomosis, while three non-responders to HO remained unchanged after surgery.
Our results indicate that some patients with completed stroke have benefit from bypass operation, and that the candidates for surgery could be selected by HO.
We assume that there are two kinds of pathological conditions in completed stroke; one is totally damaged brain (irreversible state) and the other is partially damaged brain (reversible state).
HO is not only useful as a treatment of stroke patients but also a valuable method to detect ischemic brain in reversible state.

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It has been our experiences to observe increased cerebral blood flow in unanesthetized cats in accordance with elevated systemic blood pressure following intravenous administration of norepinephrine. Based on this experiences, drug-induced hypertension was used in treatment of ischemic condition or in order to know the indication of by-pass surgery.
Material and method. Systemic hypertension was induced by norepinephrine at the dose of 10-15mg in 500ml lactated Ringer solution, which was dripped at the speed of 40-100ml/hr, to keep blood pressure above the critical level, usually between 160-200mmHg. Accumulated cases are 12, including 6 patients with vasospasm in postoperative course of aneurysmal surgery, and 6 others with various organic stenotic or occlusive condition.
Results: 1) All of 6 cases with postoperative vasospasm showed improvement in neurological status by induced hypertension. 2) Vasospasm of the artery was immediately improved to normal caliber in one case by induction of hypertension during angiography. EEG was also showed improvement in some. 3) In ischemic condition other than vasospasm, STA-MCA anastomosis was performed only when induced hypertension caused favorable effects. This seems to be reliable measure to predict the effect of by-pass surgery.

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The correlation between CBF dynamics and drug-induced EEG or somatosensory evoked potentials (SEP) has been analysed in TIA, RIND, minor or major completed stroke and rapid progressing stroke of acute cerebral ischemia.
In 4 patients with TIA, RIND and minor stroke, the CBF values were randing from 30 to 40ml/100g/min. with no apparent dysautoregulatory areas.
However, when significant decrease of mean systemic arterial blood pressure (MSABP) were brought by administration of Regitine^®, reduction of rCBF in the territory of MCA occurred and EEGs or SEPs were worsened. It is considered that the results mean the focal low perfusion phenamena in such cases.
The bypass surgery was performed in 28 cases with major completed stroke. In them, the CBF values were 25-32 ml/100g/min. with apparent dysautoregulation and disturbance of CO₂-reactivity. In cases with improvement obtained by the bypass, EEGs or SEPs (especially, SEP) were activated by induced-hypertension. This pattern was classified to the“CBF-dependence”.
In 8 patients, who were rapidly worsened during a short time after onset in acute stage, the emergency STA-MCA bypasses were carried out within 3 days of onset. The patients with changes of EEG or SEP depending on CBF were remarkably improved by the bypass.
In cases with activation of EEGs or SEPs by glycerol administration, the bypass surgery was not effective but, the external decompression was beneficial for improvement of consciousness. We call this pattern as the“intracranial pressure (ICP)-dependence”.
Accordingly, it is concluded that patients who have the patterns of the CBF-dependence in the functional EEG or SEP test would be suitable candidates for the bypass surgery in any cerebral ischemia.

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It is important to correctly predict prognostic physical function following to obstructive cerebrovascular dysfunctions including completed stroke. We have attempted to obtain reliable information as to the prognostic function from the investigation on the somatosensory evoked potential (SEP) recorded before and after the administrations of the solution of low molecular weight dextran (500ml/day) and urokinase (60,000 unit/day) for a period of 1 week to the patients of obstructive cerebral arterial dysfunction. The adaptability to the STA-MCA anastomosis of such patients was examined on the basis of the results thus obtained.
The patient subjected to the study consisted of (1) 17 patients with middle cerebral arterial obstruction and (2) 5 patients with internal carotid arterial obstruction. The amplitude of the N₂-N₃ smaller than 3μV in predosing SEP was observed in 10 cases out of 17 for the patient group (1) and 3 out of 5 for the group (2), and that larger than 3μV was recorded from 7 patients out of 17 of the group (1) and 2 groups out of 5 of the group (2). Thirteen cases out of 17 in the group (1) and 4 cases out of 5 in the group (2) showed the change of EEG to slow wave pattern, and the ADL of these patients was assessed to be the degree of 2-3 (8 patients out of 17 in the group (1) and 2 patients out of 5 in the group (2) showed walking disability).
After the drug administration, the increase in the amplitude of the N₂-N₃ to greater than 3μV, and the improvement of the EEG slow wave and of the ADL to the grade of 4 were observed in 10 cases out of 17 of the group (1) and 2 cases out of 5 of the group (2).
Eight patients whose ages were younger than 60 years were selected from 13 improved cases and they were subjected to STA-MCA anastomosis. The back pressure during the surgery was 33±11 mmHg. The postsurgical improvement of the amplitude of the N₂-N₃ to greater than 5μV and good ADL were observed in 5 patients out of 8.
In conclusion: 1) The increase in the amplitude of N₂-N₃ by the administration of a blood flow facilitating drug correlates with improvement of ADL, and it is useful for the prediction of prognostic function and may be serve as indicator for the adaptability to STA-MCA anastomosis of patients. 2) The amplitude of the N₂-N₃ recorded presurgically reflects the back pressure during the surgery.

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The various examinations available should be used to estimate the surgical indication of STA-MCA anastomosis preoperatively, and also to evaluate its effect postoperatively.
The data of cerebral angiography, CT scan, r-CBF, EEG and ophthalmodynamometry obtained from 18 cases treated by STA-MCA anastomosis in our clinic were analysed and discussed.
1) Four vessel angiography is essential not only to detect organic vascular lesions and also to evaluate the development of collateral circulation. Follow-up angiography in late postoperative period was documented interesting informations as to the changes of the collateral circulation. Mostly the donor artery via the shunt increased its diameter.
2) CT findings were usually unchanged after the surgery even if there were some clinical improvement through the operation.
3) In most of the cases, r-CBF showed improvement but not so remarkable.
4) EEG showed transient focal slow activity in the operated temporal region in the early postoperative period in half of the cases. Matas test during EEG examination might be useful to detect the surgical effect.
The evidence obtained would indicate the evaluation of direct surgical effect by examinations at rest might be difficult. The most important effect of STA-MCA anastomosis would be to increase the cerebral vascular reserve in ischemic brain. So that, some tolerance test during examinations would be useful for real evaluation of the surgical effect.

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To study pathophysiological aspects concerned to functional reversibility of cerebral ischemia, systemic arterial pressure (SAP), blood pressure of superficial temporal artery (STP) and cortical middle cerebral artery (MCP), shunt flow through STA after anastomosis (SF), regional cortical blood flow (rCBF), EEG and somatosensory evoked potentials (SEP) were recorded and analysed during STA-MCA anastomosis. Case materials consist of 4 cases of internal carotid artery (IC) occlusions and 14 cases of middle cerebral artery (MC) occlusions. All cases are completed strokes.
In the improved cases after bypass, MCPs was more than 40 mmHg and early components of SEP were already identified before bypass. After bypass, SF showed high value more than 40 ml / min. with significant augmentation of rCBF and amplitude of N₁ of SEP. But, in the unchanged cases, MCP and SF showed lower value and early components of SEPs were not activated after bypass.
MCP is reflected to collateral circulation and SF is related to increase of rCBF after bypassing.
So it is considered that MCP, STP, SF and rCBF are important factors to determine the possibility of the functional reversibility in cerebral ischemia when bypass surgery will be performed.

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It is well known that the patient with cerebral ischemia shows not only sensorimotor disturbance, but often intellectural disturbance. Authors reviewed 8 patients of internal carotid or middle cerebral artery occlusion; all were men, ranging in age from 33 to 57. Main symptoms of them on admission were aphasia, memory disturbance, difficulty in calculation and loss of spontaneity.
Superficial temporal artery (STA)-cortical middle cerebral artery (MCA) anastomoses were performed in all patients and post operative angiogram revealed good visualization of the shunt. Patients were given psychological examinations such as Wechsler Adult Intelligence Scale, Benton Visual Memory Retention Test, Kraepelin Test and Standard Language Test for Aphasia pre- and postoperatively. By analyzing the examination data, 2 patients rated good, 3 rated fair and 3 rated unchanged.
Considering the clinical course of the patients with cerebral ischemia in our series, it was concluded that the STA-MCA bypass surgery was very constructive procedure.

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Surgical indication for carotid stenotic lesions is a matter discussed for a long time but has not settled completely. Carotid stenotic lesions in Japan have been reported less frequently than in Caucasion countries and our previous studies indicate that the degree of the pathologies and a natural history of the disease are more benign. In addition, many patients (68%of total, studied) with carotid occlusive lesions either unilaterally or bilaterally had ipsilateral or bilateral intracranial arterial occlusive diseases. Accordingly, the surgical indications in Japan should include these characteristics of the disease and provide multiple situations since presence of the intra- and extracranial lesions creats multiple combinations. The authors have utilized a surgical indication for the past 4 years and performed 31 carotid endarterectomies according to the indication. The indication consists of 31 items to be checked as in a checklist.
Operative results were presented in three different periods according to the surgical indications utilized, and the results were compared with others. The result obtained from the period of present indication demonstrated an improvement in the rate (0%) of surgical failure (a rate of recurrence of preoperative neurological symptoms) but not in the mortality (3.2%). A brief discussion was made with regard to this.

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Recently, occipital (OA)-posterior inferior cerebellar artery (PICA) anastomoses have been performed for some cases with infratentorial ischemic disorder.
Until now, it is not yet enough to analyse whether the OA-PICA bypass is beneficial or not for ischemic disorders of vertebro-basilar (VA-BA) territories.
In this paper, the authors discussed some problems about the indication and the limitation of reconstructive surgery extracted from clinical courses, neuroradiological findings, and follow-up studies of 2 operated cases and 3 conservatively treated cases with survival.
In all of 3 survived cases of VA-BA occlusion, treated conservatively, Locked-in-like syndromes with alertness and tetraplegia were observed. Neuroradiologically, focal pontine infarctions were detected by CT scans but uni or bilateral patent VAs and PICAs were revealed in serial vertebral angiograms. From these findings, it is considered that the circulations in small perforating branches of BAs were disturbed.
On the other hand, 2 operated cases, which had one-sided VA occlusion with stenosis of the other, showed not enough blood flow to VA-BA territories via OA-PICA anastomoses in postoperative angiograms.
From these results mentioned above, it is suggested that the OA-PICA anastomosis would be enough to preserve the life but not complete functions of brain stems and that another methods of bypass operation with high perfusion pressure should be developed.

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Fifty five patients of ischemic cerebrovascular disease in the vertebrobasilar system were studied. On the angiographic examination, 7 patients were normal, 13 patients were only sclerotic and other 35 patient were positive Angiographic findings of these patients were as Table 2. Vertebral lesions were the most and lesions of posterior inferior cerebellar artery were the second.
The grades of recovery were classified in 4 ADL grades. It was noted that 37 patients out of 51 were recovered to full activity (ADL-1) or to daily life for oneself (ADL-2). 7 patients were required help in daily life (ADL-3) and patients were restricted in bed all day long (ADL-4). All patients except one in ADL 3·4 groups had hemiplegia, blindness and dementia because of complicated supratentorial ischemic lesions. Ataxia was not the major residual deficit. But in one patient who had the bilateral cerebellar ischemic lesions (Rt-PICA occlusion and Lt-SCA occlusion) ataxia was the major residual deficit. 2 patients who had a basilar artery occlusion were died.
From these angiographic and follow up review, ADL of ischemic cerebrovascular disease in vertebrobasilar system was relative good. On the other hand, occipital to posterior inferior cerebellar artery bypass surgery was indicated to prevent the major stroke for patients who had occlusive lesions of vertebral artery complicating TIAs, RIND or progressing deficits, not altered by anticoagulation therapy.

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Clinical trials of microvascular anastomosis between the middle meningeal artery and a cortical branch of the middle cerebral artery were reported. This anastomosis technique can be applied when the superficial temporal artery or occipital artery is not suitable for direct anastomosis to a cortical artery and the middle meningeal artery is well developed.
The technical problems and advantages compared with conventional superficial temporal artery-middle cerebral artery anastomosis were discussed.

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We studied the effect of cervical sympathectomy, consisting of superior cervical ganglionectomy (S. C. G. N.) and perivascular sympathectomy (P. V. S.) of the cervical carotid artery, on the blood flow of common carotid artery in 17 patients with cerebral ischemic lesion. At the same time, the clinical efficacy of the sympathectomy was discussed.
We measured blood flow of the common carotid artery with a square wave electromagnetic flowmeter. The average blood flow before the cervical sympathectomy (=control) is 334.8±16.3 (M±S. E. M.) ml/m. The average blood flow after the S. C. G. N. is increased in all but 4 patients as 401.7±24.7ml/m (increasing rate to control is 19.75±3.74%), and the average blood flow after the S. C. G. N, and P. V. S. is 425±31.6ml/m (increasing rate to the blood flow after the S. C. G. N. is 6.26±1.99%). Clinical condition of patients are improved following increase of blood flow in 60% of patients.
Mean arterial blood pressure and blood gas are monitored before and after the cervical sympathectomy, and we found increased blood flow is not related to the blood pressure or results of blood gas.
We believe this cervical sympathectomy is definitely worthwhile in patients with cerebral ischemic lesion.

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Prophylactic effectiveness for the brain infarction of the administration of 20% Mannitol was reported in five consecutive cases carried out carotid endarterectomy. Clamping time of carotid arteries were ranged from 29 minutes to 62 minutes with 44.4 minutes in mean.
No neurological sequela has appeared after operation. Serial electroencephalogram during carotid endarterctomy and CT findings taken after the operation showed no significant abnormalities.

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This experiment was performed to study pathophysiology of cerebral infarctions produced by segmental embolization of the middle cerebral artery (MCA) of the dog and the effect of embolectomy. A silicone rubber cylinder was injected into the cervical internal carotid artery and segmental occlusion of MCA was produced. Regional blood flow was measured in the ipsilateral temporal lobe by a hydrogen clearance method. Sensory evoked potential (SEP) was also recorded. Neurological deficits were evaluated after recovery from anesthesia. The site and extent of infarctions were ascertained quantitatively by an average end-area method. A separate group of dogs were subjected to embolectomy at 3 and 6 hours after embolization.
In most of the animals embolization resulted in a decrease of blood flow from the original value of 52.5±8.2 ml/100 g/min to 38.5±10.3ml/100g/min. Amplitude of SEP decreased to 70% of the resting level at 1 hour after occlusion and to 50% at 3 hours. These animals exhibited hemiplegia. Infarctions involved the lobus pyriformis, thalamus and caudate nucleus and their size reached 4.6cm³. Embolectomy at 3 hours after embolization restored cortical blood flow, accompanying reactive hyperemia. SEP increased to 110-120%. The animals were able to walk and the size of infarction was less than 1cm³. Out of 10 dogs in which embolus was removed after 6 hours, 5 could walk but other 5 could not walk or hardly walked and the mean infarct volume was 2.9cm³.
This study suggests that the perforating arteries of MCA play an important role in production of deep hemispheric infarction. Development of ischemic brain swelling seems to be the most serious risk factor for the prognosis. Measurements of r-CBF and SEP are beneficial to evaluation of the reversibiblity of brain function after ischemia.

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The STA-MCA anastomosis or endarterectomy for cerebral infarction is performed widely as a treatment of cerebral infarction in various neurosurgical facilities. The effect of each method, however, has not yet been clarified up to the present. The authors measured the rCBF in dog's caudate neucleus, thalamus and midbrain, to estimate the effect of the revasculization of the middle cerebral artery (MCA). The rCBF in the caudate neucleus decreased gradually, after clipping of the MCA with a Scoville clip, for 6 hrs. On the other hand, no significant change was noted on the rCBF of the thalamus and the midbrain. In all cases, no brain swelling was observed through a window in the temporal bone which had been previously made. Immediately after releasing the occlusion of MCA, the rCBF in the thalamus and the midbrain increased rapidly, and then the flow decreased gradually. However, brain swelling was observed in 5 out of 8 dogs, and no significant change was noted on the rCBF in the caudate neucleus. Decrease of the rCBF after releasing of the occlusion may be considered to be brain swelling or edema under the condition of abnormal metabolism and/or vasoparalysis. Such a condition may occur by the clipping of the MCA and releasing the occlusion, effecting the circulation of the circle of Willis.
This experimental study leads to the conclusion that the direct removal of the occlusion in a artery, such as endarterectomy, should be avoided because it will increase brain edema and make a decrease of rCBF in the thalamus and the midbrain.

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Today, there is no established therapy for acute ischemic stroke. Acute ischemic stroke is now generally accepted as progressive process, so it is important to prevent the brain from converting into irreversible states, in the period when the brain are functionally supressed but not infarcted. So this rationale, when it is supported by experimental and clinical data, suggests that direct revascularization might alleviate some ischemic strokes.
Two patients with middle cerebral artery occlusion were presented. We divided acute ischemic stroke into following three stages : First stage-it is the period soon after onset of a stroke and neurological deficits are evident but CT scanning indicates no abnomality. In some cases, revascularization can lead a substantial improvement; Second stage-it is the period of cerebral edema. CT scanning discloses low density area (LDA) with a mass effect. Main therapy should be focused upon the control of intracranial pressure; Third stage-it is completed infarct. CT scanning clearly demonstrates a well-circumscribed LDA.. Bypass or carotid surgery can prevent reccurrent ischemic stroke in some cases.
Our experience with surgical treatment of acute strokes has shown some conclusions and problems. Indications for revascularization are suggested when the following clinical criteria are satisfied: The patients should be rather young. The patient should be alert and not so severe in motor disturbance. Anterior choroidal or lenticulostriate arteries should be patent. Emergent revascularization in acute stroke awaits further development methods to differentiate ischemia from infarct, to prolong a reversible state by the administration of brain protective drugs such as barbiturate, and to perform a rapid and high flow revascularization.

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A 32-year-old man suffered from weakness and hypaesthesia of the right upper limb about eight months prior to admission. A left carotid arteriogram demonstrated marked stenosis of the left internal carotid artery at the level of the bifurcation. At seven hours after the study, right hemiplegia, aphasia and decreasing consciousness level appeared. About two hours after the onset of the symptoms, a thromboendarterectomy of the left internal carotid artery, followed by extraction of the remaining fresh clot distal to it, using No-4 Fogary catheter, was performed. Although there was good retograde bleeding, intraoperative CAG showed partial occlusion of the C-2 portion and total obstruction of the left middle cerebral artery distal to its perforators. Immediately, a left fronto-temopral craniotomy was made. Through arteriotomies made in the C₂, M₁ and M₂ portions, thrombi were removed. Interrupted sutures with 10-0 stainless-steel-wire were used for closure of the incisions. One week after the surgery, the patient became alert. 2 months later he had gained good moter power (4/5) in his right limbs and was able to walk alone. A repeated CAG showed that the left carotid and middle cerebral arteries were patent. Previous reports on this subject were reviewed.

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Two cases of cerebral infarction associated with massive cerebral edema leading to progressive deterioration within short period after the onset which was sufficiently reverted with decompressive hemicraniectomy were reported. The first case was 57 year old man with an acute onset of left hemiparesis and disturbance of consciousness on August 17, 1977. On admission three days after the onset, marked stenosis of M₁ portion of the middle cerebral artery and poor filling of the major branches with shift of the anterior cerebral artery indicating mass effect were demonstrated on carotid angiography. CT scan showed diffuse low density areas over the right hemisphere, collapsed lateral ventricle on the right side and subfalcial herniation. The patient was semicomatous, with spastic hemiparesis and dilated pupils on the right side. The downhill course of the neurological signs was noted following two days in spite of conventional conservative treatment when repeated CT scan demonstrated more marked mass effect of brain edema and downward transtentorial herniation. He became deep semicomatous, dilated pupils with decerebrate posture.Emergency decompressive hemicraniectomy was performed on August 22 when ICP measured via burr hole on the epidural space before craniectomy showed 1200 mmH₂O which declined to 250mm H₂O following dural incision. The pressure was gradually declined to a range of 400 to 500 mmH₂O within three days following the operation. The neurological signs were also gradually improved within three months when consciousness level was returned to 3 to 10 (3-3-9 classification) with residual left hemiparesis. The second case of 67 year old man with hypertension and previous several attacks of TIA who had an acute onset of speech disturbance followed by left hemiparesis on September 8, 1978 was admitted because he became stuporous. Carotid angiography demonstrated complete occlusion of the right internal carotid artery at the bifurcation of the neck. Massive cerebral edema was also noted on CT scan. Since the neurological signs were progressively aggravated and mass effect due to brain edema on the right side was significant on angiography, similar surgical decompression was carried out on September 11, 1978. The clinical signs were remarkably improved within two to three weeks when consciousness level was returned to an range of 1 to 2. The benefits of decompressive hemicraniectomy for the cases with cerebral infarction associated with massive cerebral edema showing downhill course due to intracranial hypertension and importance of ICP monitoring inter and postoperation as anestimation of the treatments were discussed.

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Recentry we have experienced a case of acute cerebellar infarction, which presented clinically as a posterior fossa mass and had been surgically treated. A 60 years old male patient had suffered from hypertension and diabetes mellitis for several years. He had sudden onset of dizziness, nausea, vomiting and headache, and was admitted to K.T. Hospital on Oct. 3 1978. On neurological examination, he was restlessness and blood pressure was 240/140 mmHg. 3 days after from onset, he became semicomatose. On Oct. 9, 6 days after from onset, he was transfered to our hospital because of further study and therapy. Papilledema on the both sides and respiratory disturbance were noted. On admission, he was semicomatose and his respiration was shallow and ataxic. The light reflex was sluggish, right gag reflex was not elicited. Right hemiparesis and both Babinski's sign, Chaddock's sign were positive.
CT scan revealed low density area at the right cerebellar hemisphere and hydrocephalus. Right VAG demonstrated the mass of lower part of cerebellum and right AICA was not visualized. Ventricular drainage was carried out for first aid therapy on the day of admission. Positive contrast ventriculography revealed anterior shift of 4th ventricle and obstruction at the lower-posterior part of 4th ventricle. After the drainage, he regained consciousness and respiratory disturbance was disappeared. 9 days after from onset, he became drowsy again. In order to relieve the brain stem compression, suboccipital decompressive operation was done (Oct, 12). At the operation, right cerebellar hemorrhagic infarction and right tonsillar herniation were noted. Torkildsen's shunt operation was placed because of poor flow of CSF from Foramen Magendie. 3 months after the operation, he has no neurological deficits except right accessory nerve palsy.

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Here we reported results of surgical therapy on 26 patients of multiple cerebrovascular occlusions (21 males, 5 females; average age 55).
Of the 26 cases, 13 cases had TIA'(s), 4 cases had RIND'(s) and 9 cases had minor stroke.
Multiple severe stenosis (more than 50%) and/or occlusions were found; 10 cases had bilateral internal carotid artery, 6 cases had unilateral internal carotid and vertebral artery, 3 cases had bilateral internal carotid and vertebral artery, 3 cases had bilateral middle cerebral artery, 2 cases had unilateral internal carotid and middle cerebral artery stenosis and/or occlusion, and 2 cases had, 4-vessel' occlusion.
Surgical procedures depended mainly on the patients, general condition, neurosurgical symptome, angio-graphic findings and other examinations; 14 cases had unilateral STA-MCA anastomosis, 8 cases had bila-teral STA-MCA anastomosis, 3 cases had unilateral STA-MCA anastomosis and carotid endarterectomy, and only one case had unilateral STA-MCA anastomosis and OA-PICA anastomosis.
The operative results were obtained as follows: 7 cases were excellent, 9 cases were good, 2 cases were fair, 4 cases were poor and 2cases died.

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For the 106 TIA cases (86 nonsurgical cases and 20 surgical cases), the recurrence ratio of repeated TIA and/or newly developed completed stroke was compared each other among nonsurgical cases and also between surgical and nonsurgical cases with reference to the angiographically demonstrated cerebral arterial lesion. In addition, the recurrence ratio of the nonsurgical cases was compared each other between those with and without anticoagulant therapy.
The recurrence ratio (the incidence of repeated TIA and/or newly developed completed stroke) in the present cooperative study can be summarized as follows;
(1) the recurrence ratio was higher in TIA patients having any angiographically demonstrable cerebral arterial lesion, especially in the internal carotid artery, than in those without.
(2) no difference of the recurrence ratios was observed between the degree of occlusive lesion.
(3) the recurrence ratio in the anticoagulated cases was lower than that in non-anticoagulated cases.
(4) the recurrence ratio in the surgical cases was lower than that of the nonsurgical cases.
The study group on TIA criteria and detection. Heyman, A. et al.: IX. Transient focal cerebral ische-mia: Epidemiological and clinical aspects. Stroke, 5: 277, 1974.

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Occlusive cerebral vascular diseases have been treated by means of extra-intracranial arterial by-pass. However, the occlusion due to an apparent embolus is excluded from indications for the by-pass surgery as well as the occlusion at the middle portion of middle cerebral artery (MCA) where perforating arteries branch.
The authors presented three cases of middle cerebral artery endarterectomy (MEA) and two cases of embolectomy, performed on patients whose MCA occlusions were contraindicated for the by-pass surgery.
Postoperative angiograms of these patients showed reperfusion of the perforating arteries and MCA in all cases. However, only two patients, who underwent embolectomy 6 and 12 hours after the onset of hemiplegia, improved remarkably postoperatively.
Serious operative complications such as hemorrhagic infarction or severe brain edema were not encountered.
Literatures were reviewed and a brief discussion was made with regard to the difference of incidence of hemorrhagic infarction and severe brain edema between clinical cases and experimental animals.

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Thirty four cases of the occlusive cerebrovascular diseases which were attributed to the extracranial carotid lesions, were managed surgically for last three and a half years. Unilateral carotid endarterectomy (CEA) were carried out in 16 cases, bilateral CEA in one, STA-MCA anastomosis (bypass) in 9, both of CEA and bypass in 5 and segmental carotid resection and reconstruction of the kinked carotid artery in 3.
Investigation of the aging factors to angiographical changes of the extracranial internal carotid arteries was carried out statistically with 403 cases of carotid angiograms, which were included 112 cases of cerebrovascular accident group and 391 cases of the control group. Grades of stenotic lesions, including the ulceration or irregularity of the vessel wall, were found rather higher rate in CVA group to the control group.
It has been considered that there were two principal theories of the cause of cerebral ischemia, namely, reduced cerebral blood flow caused by arterial stenosis and intermittent embolization from ulcerated atheromas of the carotid artery. Four vessel angiography usually performed in various angles with subtruction or high magnification method for the confirmation of these hypothesis.
Complications were found in 4 cases of 22 patients undergoing CEA. Temporary neurological deficits were observed in 2 cases after the surgery which caused systemic hypotention or prolonged occlusion of ICA during operation. One case, which had the shunt tube occlusion during surgery, had a permanent hemiparesis and another patient died from septicemia. For avoiding these complications following points are thought to be noteworthy:
1) To maintain the systemic blood pressure as high as the level of the preoperative state and to avoid the falling of the perfusion pressure less than 100 mmHg at least.
2) To shorten the clamping time of the carotid artery.
3) To remove the atheromatous plaque sufficiently. For these purposes, we are trying to perform CEA as follow:
1) Under various monitors, such as stump pressure checking, local perfusion pressure measurement, systemic pressure measurement, EEG and blood gas if necessary.
2) Using the T-shaped internal shunt in all cases.
3) And with postreconstruction angiography.

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It has been reported lately that extra-intra cranial arterial bypass procedure (EC-IC bypass procedure) had a protective effect against further clinically significant cerebro-vascular accidents in patients of transient ischemic attack (TIA) or reversible ischemic neurological dificit (RIND). It was however reported not effective for improving the neurological deficit of patients with complete stroke. We clinicians know from the experience that EC-IC bypass procedure takes sometimes good effect for the motor weakness of the patents with minor complete stroke.
It is the purpose of this report to clarify the indication of the EC-IC bypass procedure especially for the patients with minor completed stroke by the investigation of angiogram, CT findings and clinical results.
The cases consist of 31 cases, in which CT was taken and clinical courses were followed up after more than a half year.
These cases were classified by CT as: (1) diffuse large low density area (2) small locarized low density area in the internal capsule (3) small locarized low density area in the paraventricle (4) small low density area in the arterial border zone (5) no low density area.
(Results) Regarding the cases of occlusion of MCA: the cases with diffuse large low density area became poor hospital course. The cases with small locarized low density area in the paraventricle were better in clinical course than cases with low density area in the internal capsule. Regarding the cases of occlusion of IC with border zone infarction were well in hospital course.
The cases that could move the paralytic hand just after the EC-IC bypass procedure were only the cases with small low density area in paraventricle or border zone infarction or no low density area. If the CT revealed low density area in the internal capsule even surgery couldn't enable the minor stroked patients to move the paralytic hand.
(Conclusion) EC-IC bypass procedure is effective not only as a protection against another ischemic attack but also for a motor weakness of minor completed stroked patients of the following cases: 1 cases of occlusion of middle cerebral artery without low density area in the internal capsule by CT. 2 cases of occlusion of internal carotid with low density area in the arterial border zone by CT.

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Clinical results of 68 cases with ischemic brain undergoing extra-intracranial arterial bypass (EIAB) between September 1973 and August 1978 are analyzed. The vascular pathology shows internal carotid artery (IC) occlusions in 23 cases, middle cerebral artery (MC) occlusions or stenoses in 83, Moya-moya diseases in 5 and vertebral artery (VA) occlusions and stenoses in 2. They are classified to 58 completed strokes, one TIA and 9 rapidly progressive strokes in an acute stage. In 58 cases with completed stroke, 14 were improved, 10 slightly improved and 34 unchanged by the EIAB. In 9 cases with the emergency bypass within three days from onset, 5 cases were improved but one case, in which severe brain edema had already revealed preoperatively, died from postoperative hemorrhagic infarction. One case with TIA continued to be asymptomatic postoperatively. There are two cases with occipital-posterior inferior cerebellar arterial (OA-PICA) anastomosis. But both of them are completed strokes, who have been unchanged postoperatively. The authors proposed in this paper that a new method select the appropriate candidates for the emergency EIAB from severe ischemic stroke patients by a combination test of the agent-induced EEG or evoked potential, furthermore, by this new method, it is considered that the emergency EIAB should be performed for the appropriate candidates of rapid progressive strokes in acute stage to prevent severe neurological dificits for them.

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Extra- and intracranial arterial bypass operation (EIAB) was performed in 14 patients with a severe arterial stenosis (>50%) in major cerebral artery. In eight cases, the stenotic lesion was found to be occluded by postoperative angiography. Neurological symptoms (aphasia or hemiparesis) were temporalily or permanently exacerbated in three of them. The decrease of arterial pressure gradient through the stenosis, supposed to be a cause of postoperative obstruction (Figs. 1, 2).
Angiographical findings in 8 cases with postoperative obstruction
Four patients had a lesion in horizontal portion of middle cerebral artery (M₁), and another four had a lesion in internal carotid artery (C_1-5). Three patients, whose symptoms were exacerbated after operation, had a lesion in M₁ or C_1-2, where good collateral flow through communicating or ophthalmic artery was not anticipated, when the lesion was occluded. In these cases, the territory of middle cerebral artery (MCA) was anterogradically filled through the stenosis before opration. After operation, the occluded area was retrogradically filled through the leptomeningeal anastomoses, and the function of bypass was not proved, or poorly proved due to small size of superficial temporal artery (STA) or stenotic change of anastomosis. On the contrary, in 3 cases with a lesion in C_3-5, or a cases with a good collatral flow through the leptomeningeal anastomoses, symptoms were not exacerbated after operation, and even in the cases with a lesion in M₁, when the bypass function was satisfactorily established.
Conclusions: A severe stenotic lesion was sometimes occluded after EIAB operation. The operation to the cases with severe arterial stenosis, especially in M₁ or C_1-2, should be performed in attention to the followings. 1) The direction and the grade of collateral flow should be checked by four vessel angiography. 2) The operation should be performed in the patients who will be expected to have a good function of bypass (STAφ> 1mm). Double anastomoses, or anticoagulants will be useful to obtain the patency.

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During the past 5 years, we have performed STA-MCA anastomosis (superficial temporal artery-middle cerebral artery anastomosis) for 20 cases of TIA and minor stroke, while, we admitted about 300 cases of ischemic cerebrovascular accident in the same period.
Eleven cases of them were started by TIA in which 5 cases of them revealed stenosis or stricture of the internal carotid artery and 6 others had the stricture of middle cerebral artery, all at the trifurcation on carotid angiography. 3 cases of internal carotid occlusion were all in the age of fortieth and showed the collateral circulation via ophthalmic artery from the external carotid artery into the intracranial internal carotid artery on CAG. One of them revealed occlusion of bilateral internal carotid artery and therefore, had STA-MCA anastomosis bilaterally.
Nine cases of minor stroke were identified to be caused by moya-moya disease in 4 cases, by the occlusion of middle cerebral artery in 4 cases and the rest by the stricture of internal carotid artery. All 20 cases had STA-MCA anastomosis, in 3 cases bilaterally and were followed up for 5 years in the longest case. The patency of the anastomosis was proved in 17 cases.
In the follow-up study, no one had further attack any more postoperatively in the TIA group. In the group of minor stroke, two of them recovered to social life and 4 others returned to independent home life.

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Fourty-one patients with cerebrovascular occlusive diseases and one patient with a giant aneurysm of the left internal carotid artery, which had proved in capable of direct surgical ablation, underwent STA-MCA anastomosis in our service for last 4 years. The occlusive cerebrovascular disease included 11 cases of the internal carotid artery (ICA) occlusion, 23 cases of MCA occlusion and 7 cases of ICA and MCA stenosis. As clinical manifestations of these cases, 11 cases had transient ischemic attack (TIA) and/or prolonged reversible neurological deficits (PRND), a case had progressing stroke, 12 cases had minor completed stroke (mn. CS) and 17 cases had major completed stroke (mj. CS). One case of PRND was died after surgery because of unknown etiology of cerebral infarction. Postoperative course of the other cases were uneventful.
For postoperative evaluation of the effectiveness of the anastomosis, complete disappearance of TIA or PRND or significant improvements of motor or sensory deficits were evaluated as effective. The efficacies were noted 9 cases (82%) out of 11 cases of TIA and/or PRND group, 8 cases (67%) out of 12 cases of mn. CS group and 3 cases (18%) out of 17 cases of mj. CS group.
There were 14 cases which fitted the clinical criteria of the“Cooperative study of E/I arterial anastomosis (Barnett)” and the efficacy of the surgery of this group was noted in 10 cases (71%) with the patency rate of 86%of the cases. It was interesting that 2 cases had transient postoperative occlusion of the donar artery of the anastomosis. Angiographical examination suggested us that the cause of occlusion was a sort of vasospasm of the donar artery.
Lastly, it was reported that a case, 25 years old, male, who admitted to our service with chief complaint of progressing loss of vision of his left eye and severe headache, underwent the left STA-MCA anastomosis as an adjunct in the treatment of his left giant internal carotid aneurysm. The patient had the left internal carotid ligation afterwards, and his giant aneurysm, which occupied nearly full of his left middle fossa, became small as size of finger tip angiographically.

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The extra-intracranial arterial bypass operation was performed in 33 patients with ischemic cerebral vascular diseases. None of 5 patients in the TIA group was suffering from episodes of cerebral ischemia postoperatively. In two out of 7 patients in the progressing stroke group and five out of 19 cases in the completed stroke group, a marked recovery of neurological functions was noted within the first week after the operation. Two cases of moya-moya disease are included in this series. One of them, showing a completed stroke, recovered completely after the operation. In another patient of moya-moya disease with TIA, the bypass operation was performed in order to prevent attacks.
Minimum numbers of stitches had been used for anastomosis to prevent thrombotic complications based upon the results of the first animal studies which had been reported, and an intravenous infusion of low molecular dextran solution was made intra- and postoperatively in the first 11 cases. However, one of the 11 patients died of a subdural hematoma within 48 hours postoperatively and another patient with a postoperative epidural hematoma recovered up to the preoperative condition after removal of the hematoma. None of the last 22 cases received an intravenous infusion of the solution. In this group of patients, an extracranial artery was cut at 45 degree angle, and a further longitudinal incision of the artery was added in order to enlarge the anastomosing area. Then two vessels were carefully anastomosed, so that a good intimal adaptation can be obtained, with no regard to numbers of stitches grounded on the second animal studies which is described in this paper. Follow-up angiography was performed in the 31 patients. The over-all patency rate was 90.3%and 100%in the last 22 cases.
It is important in order to obtain a good patency of the anastomosed area to make anastomosis between two vessels carefully by the above method.

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Operative results for thirty cases of intracranial or extracranial occlusive diseases were analyzed and discussed. Of thirty cases of operations, twenty five external-internal arterial bypass (EIAB) operation for 17 patients having occlusive lesions in extracranial internal carotid arteries, and for 8 patients with middle cerebral arterial obstructions. Thromboendarterectomy with thromboectomy using Fogarty catheter (TE) was carried out on 5 patients with extracranial complete occlusions of internal carotid arteries. Post operative follow-up period was between 27 days and 3 months.
EIAB operations were carried out on eleven completed stroke (CS) patients, of which two showed “good” post-operative results, the other two patients “fair”, remaining 7 patients showing no post-operative improvement at all. On the other hand, five progressive stroke (PS) patients were operated by (EIAB) and one patient had “good” operative result, 2 patients “fair”, and remaining 2 patients showing no operative effects at all. None of nine patients of TIA and RIND operated by EIAB showed any post-operative reattack at all.
Four CS and one PS patients were operated by TE, of which two showed some improvement of the disorder (“good”), one slight improvement (“fair”), and one no improvement all. In remaining one PS patient in which TE was performed, it was not proved to be able to remove the thrombus for its far into intracranially contiguous firm intraarterial thrombus. According to these operative results for occlusive diseases, those patients with clinical symptoms of TIA or RIND were thought to have excellent operative indications for EIAB operations, furthermore EIAB operation was still thought to have value to be tried even for the CS or PS patients because 7 out of 16 those operated patients showed post-operative clinical improvement. Though TE operations have been reported to have occasional severe post-operative complications, no such adverse operative effect was encountered in our small number of operative cases. TE operation was therefore thought to be valuable procedure from this study, but further detail indication of the operation was still remained to be studied.

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Superficial temporal-middle cerebral artery anastomosis (STA-MCA anastomosis) has been performed in patients with TIA (4 cases) and RIND (one case). All cases were considered to be cerebral insufficiency. Two cases of patients in TIA showed excellent results. Unfortunately one case was died because of sepsis postoperatively.
I believe that STA-MCA anastomosis has a protective effect against TIA or RIND caused by cerebral insufficiency. By-pass surgery may be benefit for patients suffering from frequent TIA attacks without confirmed vascular lesions by angiography. It is felt that rCBF measurement is important diagnostic test to decide by-pass surgery for such cases. I also pointed out hemodynamic change following by-pass surgery may cause new focal cerebral ischemic lesion.

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Occlusion of the internal carotid artery is accompanied by various symptoms which are related directly to the adequecy of the external and internal collateral circulation. We have experienced STA-MCA anastomosis in two cases of complete occlusion of the internal carotid artery, followed by severe stenosis of collateral circulation.
Case. 1. A 60 year old man had a severe headache and his left extremities were rendered weak. These symptoms of TIA appeared several times in succession and progressed to a complete stroke. Right carotid angiography demonstrated a complete occlusion of the right internal carotid artery and at the origin of the middle meningeal artery of collateral circulation severe stenosis occurred.
Case 2. A 55 year old man suffered from a complete stroke with left hemiparesis, total aphasia and mental disturbance after several reoccurrences of TIA. The symptoms of these two cases were remarkably improved, when STA-MCA anastomosis were performed at the stage of a complete stroke in both cases. It may be concluded that the symptoms of both cases followed the stenosis of collateral circulation. In such cases, STA-MCA anastomosis seems to be effective in improving the symptoms even at the stage of a complete stroke. And also, we tried to show the indication of STA-MCA anastomosis for occlusion of the internal carotid artery based on the follow-up study results of cases treated conservatively. Occlusion of the contralateral internal carotid artery occurred in 3 cases of good prognosis, which caused a miserable state of death or vegetative state in later days. Therefore, we emphasize that STM-MCA anastomosis should be performed to prevent this miserable state in suitable cases even if they have a good prognosis.

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A 45-year-old man was admitted to our department with complaints of headache and speech disturbances on February 19th, 1978. A neurological examination revealed slight confusion of consciousness, disorientation and aphasia of predominantly sensory type with misunderstanding and perseveration. CT scan taken on the day of admission showed slight dilatation of the lateral ventricles, but no abnormal high or low density area was found. Left carotid angiogram disclosed occlusion of the horizontal portion of the MCA at 23mm from the bifurcation. The colateral circulation from the ACA to the MCA was also confirmed on the late arterial phase. The EEG showed slight slow activities in the left temporocentral regions. The standard language test of aphasia (SLTA) performed 24 days after attack revealed severe disturbances of the writing of the Japanese syllabary and Chinese characters. At the same time CT scan disclosed high density areas of the left middle and inferior temporal gyri by the contrast enhancement.
STA-MCA anastomosis was performed 26 days after attack. Left carotid angiogram performed 4 days after the operation showed improvement of hemodynamic pattern through the STA and the MCA. SLTA 14 days after the operation revealed much improvement of the writing of the Japanese syllabary. SLTA 60 days after the operation showed also improvement of the writing of the Chinese characters. The patient was discharged at 6 months after attack with minimum speech disturbances.

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Since 1975 we have reported good results of surgical therapy for patients with “Moyamoya” disease.
Thirty-seven patients with “Moyamoya” disease who revealed cerebral ischemic symptoms were operated; ST-MC anastomosis was performed on 30 cases, encephalo-myo-synangiosis, muscle transposition to the surface of the brain, was done on 10 cases and omentum transplantation to the surface of the brain was done on 1 case respectively. Twenty-four patients were operated bilaterally and 13 patients were done unilaterally.
Cerebral angiograms during the follow-up period after operation revealed shrinkage (decrease or diminition) of basal moyamoya vessels along with extensive filling of cortical branches of the middle cerebral artery. Basal moyamoya vessels were diminished remarkably in 1 case, moderately in 21 cases slightly or rarely in 13 cases and increased in 1 case.
The satisfactory operative results were obtained as follows: 20 cases were excellent; 11 cases were good; 4 cases were fair and 2 cases were unchanged.

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