[en] We measured the T2 relaxation time using dual spin echo MRI, and also the magnetization transfer ratio (MTR) using gradient echo MRI, in the hippocampus of Alzheimer's disease (AD) patients, and compared these factors to those of non-Alzheimer's dementia (non-AD) patients and of control subjects. The degree of medial temporal lobe atrophy in AD patients was similar to that of non-AD patients, although atrophy was more severe in AD and non-AD patients than in the control group. MTRs in the hippocampus were significantly lower in AD patients than in non-AD patients and in the control group. No significant differences in the T2 values of the three groups were found. The change of T2 x (1-MTR/100) in the hippocampus was significantly higher in AD patients than in non-AD patients and the control group and the change of T2 x MTR/100 was significantly lower in AD patients than in non-AD patients and the control group. Significant correlations between MMSE scores and MR parameters were found in AD patients, but not in non-AD patients. These results suggest that a decrease in the MTR in the hippocampus of AD, probably due to a decrease in bound water and an increase in free water, reflects underlying pathological changes which include a loss of neurons and gliosis. (author)

[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] We compared atrophy and magnetization transfer ratio (MTR) in the corpus callosum in patients with Alzheimer's disease and age-matched normal subjects. Fifteen patients with Alzheimer's disease and fourteen normal subjects received MRI. The corpus callosum was divided into three parts (anterior, middle, and posterior portions) on midsagittal slice, and their areas on T2-weighted reversed images and MTR on magnetization transfer contrast images in each portion were measured. The area and MTR decreased significantly in the posterior portion in patients with Alzheimer's disease. In the anterior portion, MTR decreased significantly, but although the area showed no significant change. In the middle portion, the area and MTR showed no significant change. MTR and the area was correlated in each portion in patients with Alzheimer's disease. The score of Hasegawa dementia scale-revised (HDS-R) and the area of the middle, posterior and total of corpus callosum were significantly related. The score of HDS-R and MTR in the anterior portion of corpus callosum were significantly related. The present study revealed decreases in MTR in the anterior portion of the corpus callosum of patients with Alzheimer's disease although the area showed no significant change, and this change suggests the increase in free water and/or the decrease in bound water in tissues, probably due to demyelination and axonal degeneration. (author)

[en] We investigated blood-brain barrier (BBB) permeability in white matter lesions of Binswanger's and Alzheimer's disease with contrast-enhanced MRI. BBB permeability was quantified by calculation of T1 change defined as [(T1post-T1pre)/T1pre], where T1pre and T1post represent the T1 relaxation times before and after Gd-DTPA administration. T1 changes in periventricular hyperintensity (PVH) of Binswanger's disease (BD) and Alzheimer's disease (AD) patients significantly decreased in comparison with that in normal white matter of the control subjects, and PVH of BD patients showed significantly decreased T1 change compared to PVH of AD. The magnetization transfer ratio (MTR), reflecting the severity of tissue damage in the white matter, significantly decreased in PVH of BD and AD patients comfarmd with normal white matter of the controls, with a significant decrease in PVH of BD patients compared to PVH of AD patients. T1 change and MTR for area of PVH significantly correlated with the MMSE score in BD, but not in AD. These results suggest that BBB permeability increases in areas of PVH in BD and AD. Moreover, increased BBB permeability may be related to a decline in cognitive impairment in patients with BD. BBB dysfunction and tissue damage may be more severe in areas of PVH in BD patients than that in AD patients. (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] We investigated the changes in water diffusion in the cerebral white matter and the corpus callosum in 12 patients with Binswanger's disease (BD), and 19 patients with Alzheimer's Disease (AD), including 12 without (AD-) and 7 with periventricular hyperintensity (PVH) lesions (AD+), using diffusion-weighted magnetic resonance imaging (MRI). Apparent diffusion coefficients (ADCs) in the anterior and posterior white matter were significantly higher in patients with BD and AD than in 12 age-matched controls. The ADCs were significantly higher in AD (+) than in AD (-) patients. Anisotropic ratios (ARs), defined as diffusion restricted perpendicular to the direction of the nerve fibers, were significantly higher in BD and AD (+) patients, and even in AD (-) patients, than in the controls. ARs in the anterior white matter were significantly higher in BD than in AD (+), while in the posterior white matter the ratios were significantly higher in AD (+) rather than BD patients. The ADCs and ARs in the genu of the corpus callosum were significantly higher in patients with BD and AD (+) compared to the control subjects, while ADCs and ARs in the splenium were significantly higher in patients with AD (+) and AD (-) than in those with BD. These results suggest that mild myelin loss occurs in AD patients even in apparently normal white matter and in the splenium of the corpus callosum. A definite loss of myelin and axons, including incomplete infarction, occurs preferentially in anterior white matter in BD, while in posterior white matter in AD (+), as seen on T2-weighted images as PVH. Studies with diffusion-weighted MRI may allow the characterization of different pathological processes and enable the demonstration of underlying white matter lesion in patients with dementia that cannot be visualized by conventional MRI. (author)

[en] We attempted to investigate whether morphological features as shown on magnetic resonance imaging (MRI) predict response to donepezil treatment in patients with Alzheimer's disease (AD). Sixty-three patients with AD were divided into responders (n=16) and non-responders (n=47) based on the changes in the mini mental state examinations (MMSE) score between baseline and endpoint. Atrophy of the substantia innominata was more pronounced in responders than non-responders. Although no significant difference in the medial temporal lobe atrophy between responders and non-responders was found, magnetization transfer ratios (MTRs) of the hippocampus and parahippocampus, indicators of structural damage, in the non-responder group were significantly reduced compared to those in the responder group. There were no significant differences in the severity of white matter lesions between the two groups. Logistic regression analysis revealed that the overall discrimination rate was 81%, with 85% of non-responders and 69% of responders, through measurement of the thickness of the substantia innominata and MTR of the hippocampus and parahippocampus. These results suggest that AD patients who show more severe cholinergic dysfunction and less severe structural damage of the hippocampus and parahippocampus as shown on MRI are likely to respond to donepezil treatment. (author)

[en] Using magnetization transfer (MT) imaging, we studied the underlying pathological conditions of periventricular hyperintense (PVH) white matter changes seen on T2-weighted MR images of patients with multi-infarct dementia. Twenty-two patients with multiple lacunar infarcts and PVH lesions, including 11 with dementia (diagnosed as multi-infarct dementia) and 11 without dementia, and 10 control subjects (with multiple lacunes, but no PVH lesion) were studied using the MT technique. MT ratios (MTRs) were calculated for PVH lesions (normal-appearing frontal white matter in controls) and the genu of the corpus callosum. Signal intensities on T2-weighted images in PVH lesions of patients were significantly higher than those in normal-appearing white matter of controls, while there were no significant differences in signal intensity in the genu of the corpus callosum among the dementia, non-dementia and control groups. However, MTRs in patients with PVH lesions were significantly lower than those in controls, and MTRs in demented patients were significantly lower than those in non-demented patients. Moreover, MTRs in the genu of the corpus callosum of demented patients were significantly lower than in those in non-demented patients and controls. MTRs in PVH lesions and the genu of the corpus callosum significantly correlated with Hasegawa's dementia scale score. These results suggest that there is some difference in histopathologic changes of PVH lesions between demented and non-demented patients and that the pathological substrate in the corpus callosum may play a role in inducing cognitive decline. Studies with MT imaging may allow the characterization of different pathological conditions that cannot be visualized by conventional MRI. (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] We compared the diagnostic usefulness of three-dimensional stereotactic surface projection (3D-SSP) with that of standard transaxial images in brain SPECT in patients with Alzheimer's disease (AD). The subjects consisted of 69 patients with AD and 60 patients with non-AD, including vascular dementia, Parkinson's disease with dementia, frontotemporal dementia, other dementing diseases and neuropsychiatric diseases. Standard transaxial section and 3D-SSP SPECT images with N-isopropyl-p-[¹²³I] iodoamphetamine were blindly interpreted by three examiners and were classified into the following three patterns: typical AD, atypical AD, and not indicative AD patterns. The 3D-SSP images demonstrated reductions of cerebral blood flow in the parieto-temporal association cortex and posterior cingulate gyrus more clearly and easily than the standard transaxial images. The diagnostic sensitivity and specificity were 93% and 85% with 3D-SSP and 83% and 82% with standard transaxial section respectively. 3D-SSP was especially useful for early or atypical AD which showed no characteristic perfusion abnormalities on standard transaxial images. These results suggest that SPECT with 3D-SSP provides an sensitive as well as accurate tool for the diagnosis of AD. (author)