Biomedical subjects

Akira Kunimatsu

Publications and source records attributed to Akira Kunimatsu.

3 recordsLinked to original sources

PubMed2003

MR imaging of ischemic penumbra.

Cerebral ischemic stroke is one of the most fatal diseases despite current advances in medical science. Recent demonstration of efficacy using intravenous and intra-arterial thrombolysis demands therapeutic intervention tailored to the physiologic state of the individual tissue and stratification of patients according to the potential risks for therapies. In such an era, the role of the neuroimaging becomes increasingly important to evaluate the extent and location of tissues at risk of infarction (ischemic penumbra), to distinguish it from unsalvageable infarcted tissues or doomed hemorrhagic parenchyma. In this review, we present briefly the current role and limitation of computed tomography and conventional magnetic resonance imaging (MRI). We also present the possible applications of advanced MR techniques, such as diffusion and perfusion imaging, concentrating on the delineation or detection of ischemic penumbra.

Brain Ischemia↗

PubMed2003

[Simple visualization of the corticospinal pathway using tractography: one-ROI and two-ROI methods].

Diffusion tensor imaging (DTI), a magnetic resonance (MR) technique to analyze diffusion anisotropy of the brain, is able to demonstrate subtle white matter anatomy. Tractography is expected to be a unique, non-invasive tool to provide more pertinent insights into brain structure and orientation not accessible by conventional MRI. In this report, preliminary experiences of visualization of the corticospinal tract using tractography are described. DTI of the brain was performed in 5 normal volunteers using single-shot echo-planar imaging, then tractography was generated by our original software. We determined that the two-region-of-interest (ROI) method is superior to the one-ROI method.

Adult↗

PubMedDate not supplied

Normal aging in the central nervous system: quantitative MR diffusion-tensor analysis.

The purpose of this study is to elucidate changes in mean diffusivity (ADC) and fractional anisotropy (FA) using MR diffusion tensor imaging (DTI) in the central nervous system during normal aging. We studied 50 normal volunteers (30 men, 20 women; mean age 44.8 +/- 14.0; age range, 21-69 years) without disorders affecting the central nervous system. The frontal, parietal white matter, lentiform nucleus, posterior limb of internal capsule, thalamus, genu and splenium of the corpus callosum were selected for investigation. There was no significant difference in ADC or FA between male and female or between the right and left hemisphere. A significant ADC increase with advancing age was observed in frontal white matter (P = 0.010) and lentiform nucleus (P = 0.022). A significant FA decline was found only in the genu of the corpus callosum (P < 0.001) with advancing age. Quantitative diffusion tensor analysis correlate with normal aging and may help in assessing normal age-related changes and serve as a standard for comparison with neurodegenerative disorders.

Adult↗