[en] Internal carotid artery (ICA) occlusion presents a broad spectrum of clinical manifestations ranging from death due to extensive infarction to absence of neurological deficit and infarction. In order to evaluate the relationship between the obstructive mechanism of ICA occlusion and the effect of this phenomenon on cerebral parenchyma, both CT scans and angiograms of forty-eight cases of ICA occlusion (eighteen cases of embolism and thirty of thrombosis) were reviewed. The size and location of low density areas (LDA), the presence of mass effect and the responce to contrast enhancement demonstrated on CT scans were analysed in relation to angiographic findings. About 90% of these cases demonstrated various sizes of LDA on CT. In this study, a large infarction was defined as LDA larger than 2/3 of the hemispheric area and a small infarction as LDA smaller than 1/3 of the hemispheric area. 61% of patients with embolism presented with large infarctions, with many being total infarctions of the cerebral hemisphere or middle cerebral artery (MCA) territory. On the contrary, small infarctions accounted for 67% of thrombotic cases. Most of them were partial infarctions of MCA territory; other small infarctions were distributed in various regions including watershed infarctions (27% of thrombotic cases). The frequency of mass signs was higher in embolism (78%) than in thrombosis (17%). Contrast enhancement was seen in 97% of embolic cases and 44% of thrombosis. (J.P.N.)

[en] To determine whether a functional relationship between the cerebrum and cerebellum exists in normal subjects, the correlation between asymmetry in cerebral blood flow and asymmetry in cerebellar blood flow was investigated. Twenty-one healthy right-handed subjects were studied using SPECT with N-isopropyl-p-(¹²³I)iodoamphetamine while in a resting state. The asymmetry index (AI) for both the cerebral and cerebellar hemisphere was calculated as follows. AI=right side - left side/right side + left side/200 (%). A negative correlation was found between AI in the cerebellum and AI in the cerebrum. Especially, AI in the cerebellar hemisphere was significantly correlated with AIs in the upper frontal cortex (r=-0.58, p<0.01), middle frontal cortex (r=-0.55, p<0.02), lower frontal cortex (r=-0.49, p<0.05), and mean cerebral hemisphere (r=-0.52, p<0.02). These results suggest the existence of a functional relationship between the cerebral hemisphere and the contralateral cerebellar hemisphere in the resting state of normal subjects. We strongly suspect that the frontal cortex exert an influence on the function in the contralateral cerebellum, probably due to a transneuronal mechanism, mainly through the corticopontocerebellar pathway. (author)

[en] In tracranial hemorrhage in leukemia was clinicopathologically studied in 62 cases of autopsy materials, with special attention paid to a morphological comparison of CT images with pathological findings. Intracranial hemorrhage was found in 32 of the 62 leukemic patients (51.6%), and in 13 of these patients (21.0%) it was responsible for death. Leukemic intracranial hemorrhage occurred more often in the acute leukemic type than in the chronic type, and even more often in younger leukemic patinents; it was pathologically characterized by multiple lesions in the white matter of the cerebral hemisphere, prone to combination with SAH or SDH. The hemorrhages could be divided into five types: (1) scattered small hemorrhagic type, (2) hematoma type, (3) fusion type (large hemorrhage composed of assembled small hemorrhages), (4) SAH type, and (5) SDH type. Among these types, the fusion type was considered to be characteristic of leukemia. CT was undertaken in 5 pathologically proven cases, with findings of the scattered small hemorrhagic type in 1, of the SDH type in 3, and of the fusion type in 1. Yet, one case with scattered small hemorrhages and two cases with SDH failed to be detected by CT. However, one case with a typical fusion hemorrhage was found to have multiple, irregular, high-density areas with surrounding edema and a mass effect as well as pathological findings. Therefore, a large-fusion hemorrhage, which is one of the most characteristic types of leukemic intracranial hemorrhage, could be demonstrated as distinctive CT images which reflected neuropathological findings. On the other hand, small parenchymal hemorrhages and relatively thin subdural hemorrhages could not be detected by CT. In conclusion, it seems that CT has value in the diagnosis of intracranial hemorrhage in leukemia. (J.P.N.)

[en] Cerebral blood flow was quantitatively measured using ¹²³I-IMP SPECT by photic stimulation and visual evoked potential (VEPs) in normal and dementia subjects: 8 with Alzheimer-type dementia, 9 with cerebrovascular dementia and 7 normal elderly subjects were divided into the three groups based on the Clinical Dementia Rating (CDR) grade: Group I (CDR 0), Group II (CDR 0.5-1), Group III (CDR 2-3). The ¹²³I-IMP SPECT measurement was conducted at rest with the eyes closed and also during photic stimulation. VEPs were measured simultaneously. The results reveal prolongation of the P2 latency of the VEPs prolonged in accordance with the increasing severity of the dementia, and quantitative cerebral blood flow was lower in Group II and Group III than in Group I at rest, while during photic stimulation it significantly increased in Group I and II, but showed no change in Group III. The results suggest that quantitative measurement of cerebral blood flow using ¹²³I-IMP SPECT by photic stimulation may enable more detailed assessment of brain cell function. (author)

[en] Parkinson's disease (PD) is often associated with dementia in elderly patients, and sometimes PD coexists with senile dementia of the Alzheimer type (SDAT) or cerebrovascular disease (CVD) in the elderly. However, since there are few previous clinical studies on the coincidence of, or relationship between PD and CVD, the authors evaluated these aspects in 34 elderly patients with PD using MRI and SPECT. All the patients were over 70 years old. The diagnosis of PD was based on the presence of three symptons (resting tremor, cogwheel rigidity and bradikinesia) which are characteristic of PD, and the effectiveness of L-DOPA therapy. We therefore believe that patients with vascular Parkinsonism were excluded from our study. In 34 cases, 24 (71%) had MRI evidence of CVD (mainly the lacunar state). In the 10 cases who had no CVD, 2 (20%) had severe dementia and the decrease of regional cerebral blood flow (rCBF) in the temporal and parietal lobes bilaterally correlated with the SPECT findings commonly found in SDAT. A comparison of the rCBF and the results of Hasegawa's dementia score (HDS) (verbal intelligence score) was made between the patients with PD associated with CVD and the patients with PD who had no CVD and no SPECT findings which correlated with SDAT. The rCBF in the frontal lobes and the results of the HDS of the former group were significantly lower than those of the latter. As mentioned above, elderly patients with PD often had CVD, leading to dementia. We also pointed out the difficulty in making a differential diagnosis between PD with CVD and vascular Parkinsonism, and the necessity of whether or not the concept of 'mixed type Parkinsonism' should be considered. (author)

[en] ¹²³I-IMP SPECT was performed to study regional hemodynamics in basal ganglia infarction due to different pathological mechanisms. Non-lacunar infarction caused by main trunk occlusion or severe stenosis showed more extensive and marked reduction of peri-infarct and ipsilateral cerebral cortical blood flow, and demonstrated distinct differences compared with lacunar infarction on SPECT images. Inadequate perfusion or incomplete ischemic lesions undetected by X-ray CT were considered to be present in surrounding and cortical areas of non-lacunar infarction involving large vessel arterial disease. (author)

[en] Since the introduction of CT scanning, correlations between neuropsychological findings and anatomical lesions have been studied. Anatomical studies by CT scans may, however, be misleading in delineating the extent of lesions in aphasia. We have carried out MRI (magnetic resonance imaging) and SPECT (single photon emission CT) examinations in 15 aphasic patients with cerebrovascular disease and discussed the usefulness of these studies. Compared to CT scan, MRI or SPECT studies were considered to be very useful in 8 of 15 patients. The useful points of these studies were: 1) easy detection of lesions with undetectable damages on CT, 2) demonstration of functional abnormalities in areas adjacent or distant from cerebrovascular lesions, and 3) precise definition of topographical abnormalities because of the three-dimensional imaging capability of MRI. As MRI or SPECT may define the actual extent of lesions and show areas of functional abnormality, these studies are useful and necessary in the assessment of lesions causing aphasia. (author)

[en] In order to evaluate the relationship between CT and angiographic findings, especially the degree of collateral circulation estimated by 4-vessel study, 47 cases with internal carotid artery occlusion were studied. The CT findings showed large infarction in 16 cases and small infarction in 24, but 7 cases had no infarction. The angiography demonstrated contralateral internal carotid stenosis in 5 cases, contralateral A₁-hypoplasia in 3 cases, and occlusio-supra-occlusionem in 6 cases, in addition to internal carotid artery occlusion (5 cases with pilateral internal carotid artery occlusion). Markedly apparent collaterals were seen; ophthalmic anastomoses (Oph.) in 30 %, via the circle of Willis (CW) in 53 %, and leptomeningeal anastomoses (LM) in 30 %. In CW, cross-filling was seen, mainly through the anterior communicating artery in the anterior cerebral artery (ACA) and middle cerebral artery (MCA) region. LM was seen mainly as back-flow from posterior cerebral artery to ACA/MCA region. Among the various combinations of collaterals, 46 % were Oph (-) + CW (++), + LM (- ∼ +). The size of the infarcted area generally depended on CW. But since 28 % of CW (++) presented large infarctions of the MCA region it is likely that either an occlusio-supra-occlusionem or a propagation of secondary thrombosis from occluded site temporarily blocked the cross-filling through CW. On the other hand, in CW (- ∼ +) the combination of Oph and LM determined the size of the infarcted area. But large infarctions were seen in 36 % of the Oph(+)/LM(++) combination, suggesting that the speed of occlusion of the internal carotid artery influenced the formation of an infarction. That is, the rapid occlusion made the infarcted area larger due to arteriolo-arteriolo anastomoses of Oph and LM. (J.P.N.)

[en] In order to determine the distribution and frequency of infarction due to occlusion or stenosis of middle cerebral artery (MCA) trunk, 223 patients with occlusion or stenosis at levels from M1 to M2 were studied according to angiographic (AG) findings and computed tomography (CT) with emphasis on the mechanisms of obstruction, such as embolism. Patients were divided into 4 groups; 84 cases of M1 occlusion (G-I), 88 cases of M2 occlusion (G-II), 31 cases of M1 stenosis (GII) and 20 cases of M2 stenosis (G-IV). CT findings, which revealed LDA in 199 patients, were classified into 8 types on the basis of the branch artery territory as follows; S+D type (60 cases), D+WB type (47 cases), S type (45 cases), B type (18 cases), WB type (15 cases), D type (10 cases), H type (3 cases) and WM type (1 case). Though the S+D type and D+WB type were seen frequently in G-I. When patients with embolism are included in the groups, 85% and 77% were thought to be due to M1 occlusion, respectively. While a half of the S+D types were caused by embolism, almost none of the D+WB types were due to embolism. This suggested that infareted area in nonembolic obstruction at the level of M1 creates smaller lesion with a sufficient collateral circulation through leptomeningeal anastomoses. Eighty percent of S type lesions were seen in M2 lesion (G-II, IV). All the B types, in which the LDA was localized to the subcortical white matter, were seen in nonembolic obstruction of G-II-IV. WB type, seen in G-I-III, and D type, were seen in 9% of M1 lesions and were infrequently caused by embolism. WM type and H type were considered to be associated with the other arterial lesions. (J.P.N.)

[en] The authors have sometimes experienced cases of frozen gait without any other manifestations of parkinsonisms in the elderly, so we examined these cases using MR imaging and SPECT imaging. The group with frozen gait (4 cases, aged 78 to 82 years) which failed to respond to L-dopa therapy, had no limb-kinetic apraxia or frontal signs, but did exhibit 'kinesie paradoxale'. The clinical symptoms of case 4 were consistent with so-called 'pure akinesia'. CT findings in this group failed to elucidate the pathogenesis of frozen gait. MR imaging of all of the cases except for the case of pure akinesia (case 4) revealed a high signal intensity areas in subcortical lesions (especially the frontal area). Case 4 had only a few spotty high-signal intensity areas. We then compared 6 cases which have the same lesions (on MRI) as cases 1∼3 without frozen gait in cases 1∼3 using ¹²³I-IMP SPECT. Relatively low accumulation of radionuclide in the frontal area was observed in these cases. Case 4 had a slightly low perfusion area in the frontal lobe. However in the patient treated with L-threo-DOPS, accumulation of radionuclide in the frontal area increased slightly after L-threo-DOPS therapy. It appears that one of the reasons for frozen gait in the elderly is incomplete infarct of the subcortical white matter with a low perfusion area in the frontal cortex. Furthermore, in some cases of frozen gait it is difficult to distinguish between cases with white matter disorders and cases of pure akinesia on the basis of clinical symptons and CT alone. (author)