Biomedical subjects

Mieko Matsui

Publications and source records attributed to Mieko Matsui.

5 recordsLinked to original sources

PubMed2006

Interactive segmentation of the cerebral lobes with fuzzy inference in 3T MR images.

Measurement of volume and surface area of the frontal, parietal, temporal and occipital lobes from magnetic resonance (MR) images shows promise as a method for use in diagnosis of dementia. This article presents a novel computer-aided system for automatically segmenting the cerebral lobes from 3T human brain MR images. Until now, the anatomical definition of cerebral lobes on the cerebral cortex is somewhat vague for use in automatic delineation of boundary lines, and there is no definition of cerebral lobes in the interior of the cerebrum. Therefore, we have developed a new method for defining cerebral lobes on the cerebral cortex and in the interior of the cerebrum. The proposed method determines the boundaries between the lobes by deforming initial surfaces. The initial surfaces are automatically determined based on user-given landmarks. They are smoothed and deformed so that the deforming boundaries run along the hourglass portion of the three-dimensional shape of the cerebrum with fuzzy rule-based active contour and surface models. The cerebrum is divided into the cerebral lobes according to the boundaries determined using this method. The reproducibility of our system with a given subject was assessed by examining the variability of volume and surface area in three healthy subjects, with measurements performed by three beginners and one expert user. The experimental results show that our system segments the cerebral lobes with high reproducibility.

Algorithms↗

PubMed2003

[3.0T imaging].

Explore the source record for details and available documents.

Humans↗

PubMed2002

Differences in cerebral metabolic impairment between early and late onset types of Alzheimer's disease.

UNLABELLED: The purpose of this study was to delineate the specific patterns of cerebral glucose metabolism with regard to the time of onset of Alzheimer's disease (AD). METHODS: Two groups of 20 AD patients with different ages of onset were examined. The early onset (EO) and late onset (LO) groups had mean ages of onset of 53.9 and 72.7 years. Groups of age-matched normal subjects were used as controls. A regional relative cerebral glucose metabolic image of each subject was obtained by 2-[18F] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET). NEUROSTAT program was used for spatial normalization and voxel-based statistical parametric mapping (SPM) 99 was used for statistical analyses. RESULTS: Both AD groups had significant hypometabolic regions in the bilateral parieto-temporal regions compared with the age-matched groups. The EO group had more severe hypometabolism in the bilateral parietal and posterior cingulate cortices and precuneus region than the LO group. However, LO group showed no significant hypometabolic regions compared to the EO group. CONCLUSION: The effects of time of AD onset were delineated as a double dissociation, that is, EO AD patients have a more severe reduction of glucose metabolism. Our finding suggests the existence of biological subtypes of AD.

Adult↗

PubMed2002

Gender differences in cerebral glucose metabolism: a PET study.

OBJECTIVE: Some studies have examined gender differences in brain function based on cerebral blood flow and cerebral metabolism by using positron emission tomography (PET). However, the findings of these studies are controversial and most of them were analyzed by the regions of interest (ROIs) method. Here, we evaluated gender differences of cerebral glucose metabolism under the resting state in a voxel-based analysis. METHODS: We studied 44 healthy volunteers (22 females, 63.0+/-6.3 years, and 22 males, 63.1+/-8.4 years). Cerebral glucose metabolic images were obtained with (18)F-fluorodeoxyglucose (FDG) and PET. All individual data were transformed to standard brain space and the male and female groups were compared using statistical parametric mapping (SPM). RESULTS: The males had significantly higher glucose metabolism in the right insula, middle temporal gyrus, and medial frontal lobe than the females. Glucose metabolism in the hypothalamus was significantly higher in females than in males. There was a significant correlation between aging and glucose metabolism in the left thalamus in males and in the left caudate nucleus and hypothalamus in females. In males, but not females, there was a significant asymmetry between the bilateral hemispheres. CONCLUSION: We found that there were obvious gender differences in regional cerebral glucose metabolism and this is the first report of higher glucose metabolism in the hypothalamus in females than in males.

Aged↗

PubMed2002

Accelerated hippocampal atrophy in Alzheimer's disease with apolipoprotein E epsilon4 allele.

Although apolipoprotein E epsilon4 is an established risk factor for Alzheimer's disease, its effect on the rate of progression of Alzheimer's disease remains unknown. The purpose of this longitudinal study was to elucidate whether the rate of hippocampal atrophy is a function of the apolipoprotein E genotypes and severity of disease. Fifty-five patients with probable Alzheimer's disease were the subjects. The annual rate of hippocampal atrophy was determined by using magnetic resonance imaging repeated at a 1-year interval. On a two-way analysis of variance, the effect of the apolipoprotein E epsilon4 allele on hippocampal atrophy was significant, but neither the effect of severity nor the interaction term was significant. In further analysis with one-way analysis of variance, the mean annual rate of hippocampal atrophy was significantly different between the groups of patients with (9.76 +/- 4.27%) and without the apolipoprotein E epsilon4 allele (6.99 +/- 4.24%). Apolipoprotein E epsilon4 dose was significantly correlated with the rate of hippocampal atrophy (rs = 0.277, Spearman rank correlation coefficient), suggesting a gene dose effect. The involvement of the apolipoprotein E epsilon4 allele in the progression of hippocampal atrophy has implications for therapeutic approaches in Alzheimer's disease and should be taken into consideration in longitudinal studies including clinical drug trials.

Aged↗