[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] 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] To investigate changes in water diffusion in the hippocampus in Alzheimer's disease (AD), diffusion-weighted MRI (DWI) studies were performed on 12 patients with AD (6 with possible AD and 6 with probable AD) and 7 age-matched controls. Apparent diffusion coefficient (ADC) values in the hippocampal body were calculated for each of the three orthogonal axes by applying diffusion sensitizing gradients in horizontal, vertical, and fore directions. There was no significant difference between patients and controls in ADC values. Study with DWI may not be a useful method for detecting underlying pathological conditions in the hippocampus in AD. (author)

[en] Magnetization transfer (MT) contrast images of the brain were obtained in 17 patients (30 studies) with supratentorial cerebral infarction, and the changes in MT effects (Moff-Mon/Moff) expressed as the ratio of lesion to control (L/C ratio) were assessed over time. Acute infarct lesions could not be detected or were relatively slight on the MT contrast images. However, subacute and chronic infarcts were shown with a low signal intensity, and the L/C ratios at these periods were significantly lower than those in at the acute stage. A significant correlation was noted between the L/C ratio and days after onset of stroke. MT contrast imaging is useful in the assessment of ischemic stroke, particularly at the subacute and chronic stages, and can assist in determining the age of cerebral infarcts. (author)

[en] We performed diffusion MRI studies in 14 patients with extensive ischemic leukoencephalopathy, including 9 with dementia (diagnosed as Binswanger's disease), and 5 without dementia, and 8 age-matched controls. Apparent diffusion coefficients (ADCs) in anterior and posterior periventricular white matter were significantly higher in demented and non-demented patients than in the controls, and diffusion anisotropy disappeared in patients because of the high ratio of the diffusion coefficients perpendicular to the nerve fibers to those parallel to the nerve fibers. ADCs in the corpus callosum were significantly higher in demented patients than in non demented patients and controls. Therefore, diffusion anisotropy disappeared only in demented (Binswanger's disease) patients. These results suggest that the cerebral white matter lesions in Binswanger's disease reflect a decrease of nerve fibers and diffuse myelin loss, and that the loss of nerve fibers in the corpus callosum may play a role in inducing cognitive decline. Diffusion MRI may be useful in the pathophysiological evaluation of cerebral white matter lesions. (author)

[en] We compared characteristic features in ischemic stroke lesions from the hyperacute to the chronic stage on diffusion-weighted (DW) and magnetization transfer (MT) images with those on T2-weighted (T2W) images, and assessed changes in apparent diffusion coefficient (ADC), MT effect (MTe), and T2 ratios (infarct/normal) over time. DW images were particularly useful for detecting hyperacute infarcts within 6 hours of onset and in distinguishing acute lesions from chronic lesions. ADC ratios were lower within 7 days after onset and rose toward 1.0 in the subacute phase, becoming relatively isotense on ADC maps, but elevated thereafter. Although MTe ratios were unchanged or only subtly changed in the acute stage, they became significantly lower in the subacute and chronic stages. These combined magnetic resonance (MR) techniques were useful in the assessment of ischemic stroke and facilitated the determination of the age of cerebral infarct. (author)

[en] To investigate age-related changes of diffusional anisotropy in the cerebral white matter, we performed diffusion-weighted MRI studies in 21 normal subjects aged 25 to 96 years. The anisotropic rations (ARs), defined as the apparent diffusion coefficients perpendicular to the nerve fibers to those parallel to the nerve fibers, were significantly higher in elderly than in young subjects in the anterior and posterior white matter surrounding the lateral ventricle. Moreover, significant correlation between age and AR was found in the anterior white matter. The ventricular index (VI) measured on MRI, as a quantitative indicator of brain atrophy, was significantly higher in elderly than younger subjects, and significantly correlated with AR in the anterior white matter. Multiple regression analysis demonstrated that the VI showed the highest correlation for AR. On the other hand, there was no significant correlations between ARs in the corpus callosum and age. These results suggest that morphological changes in the myelin and axon in the white matter occur in elderly normal subjects, probably due to neuronal loss with aging. (author)

[en] We evaluated a new semiquantitative procedure to more easily and objectively estimate the striatal uptake of ¹²³I-FP-CIT in patients with Parkinsonian syndrome (PS) and essential tremor (ET), using an anatomical standardization method, the Neurostat. Eleven patients with PS and 8 with ET were examined by clinical assessment and ¹²³I-FP-CIT SPECT imaging. The modified Hoehn and Yahr Staging Scale and Unified Parkinson's Disease Rating Scale (UPDRS) were used to assess the stage and severity of the disease. The co-registered MR and SPECT images were created with fusion software included in Neurostat. On the cross section, which shows the largest area of striate, irregular shaped regions of interest corresponding to the striate and occipital cortex were drawn. Then the ratio of specific striatal uptake to non-specific occipital cortex, V3''(F), was calculated. Another calculation was done by VOIClassic, which is a software included in Neurostat to estimate the counts per voxel of anatomically defined regions such as caudate nucleus, putamen, occipital cortex, and total cortex. Using these count data, the ratio of specific striatal uptake to non-specific occipital cortex, V3''(OC), and total cortex, V3''(TC), was calculated. A fair linear correlation was observed between V3''(OC) and V3''(F) (y=1.53x+1.40; r=0.756; p<0.01), as well as between V3''(TC) and V3''(F) (y=1.24x+1.43; r=0.713; p<0.01). Both V3''(OC) and V3''(TC) yielded similar tendencies. Concerning discrimination between ET and PS, there was a significant difference between the mean V3'' of PS and ET (p<0.01). Concerning the correlation between V3'' value and the severity of PS, the UPDRS motor score significantly correlated with the V3''(F) value (r_s=-0.816). However, V3''(OC) and V3''(TC) correlated less with UPDRS (r_s=-0.667 and -0.645, respectively). Semiquantitative parameters, V3''(OC) and V3''(TC), calculated by VOIClassic including the Neurostat system are useful and easily calculable parameters as well as V3''(F) for the differential diagnosis of PS from ET. (author)

[en] Studies with single photon emission computed tomography (SPECT) have shown temporoparietal (TP) hypoperfusion in patients with Alzheimer's disease (AD). We evaluated the utility of this findings in the diagnosis of AD. SPECT images with ¹²³I-iodoamphetamine were analyzed qualitatively by a rater without knowledge of the subject's clinical status. Sixty-seven of 302 consecutive patients were judged as having TP hypoperfusion by SPECT imaging. This perfusion pattern was observed in 44 of 51 patients with AD, in 5 with mixed dementia, 8 with cerebrovascular disease (including 5 with dementia), 4 with Parkinson's disease (including 2 with dementia), 1 with normal pressure hydrocephalus, 1 with slowly progressive aphasia, 1 with progressive autonomic failure, 2 with age-associated memory impairment, and 1 with unclassified dementia. The sensitivity for AD was 86.3% (44 of 51 AD), and the specificity was 91.2% (229 of 251 non-AD). Next, we looked for differences in perfusion images between patients with AD and without AD. Some patients without AD had additional hypoperfusion beyond TP areas: deep gray matter hypoperfusion and diffuse frontal hypoperfusion, which could be used to differentiate them from the patients with AD. Others could not be distinguished from patients with AD by their perfusion pattern. Although patients with other cerebral disorders occasionally have TP hypoperfusion, this finding makes the diagnosis of AD very likely. (author)

[en] To evaluate the efficiency of dynamic contrast-enhanced magnetic resonance imaging (MRI) for the diagnosis of salivary gland masses. We retrospectively examined 19 salivary gland masses that were pathologically diagnosed by surgical operation or biopsy. We obtained T1- and T2-weighted images on MRI, performed dynamic studies on each mass and examined the correlation between enhancement patterns and pathological findings. Four enhancement patterns were recognized on contrast-enhanced MRI: type 1 showed marked, homogeneous enhancement; type 2 slights, homogeneous enhancement; type 3 marginal enhancement; and type 4 poor enhancement of the mass. Most pleomorphic adenomas had a type 1 enhancement pattern, but two had a type 2 pattern. Pathologically, each mass enhancement pattern had different tumor cell and matrix components. Warthin's tumor generally showed the type 4 pattern. Primary malignant tumors of the salivary gland all showed the type 3 pattern, and pathological specimens showed many tumor cells along the marginal portion of the tumor. One inflammatory cyst and one Warthin's tumor also showed the type 3 pattern. Except for metastatic renal cell carcinoma, the enhancement patterns of late phase images and dynamic study images were the same. Dynamic MRI added little diagnostic information about salivary gland masses, but the contrast-enhanced MR features correlated well with the pathological findings. (author)