I have validated in vivo methods of estimating volumes of subcortical structures utilizing MRI and sterology. These studies have suggested that depressed patients have smaller caudate, smaller putamen, altered water balance in the hippocampus, a smaller medulla and cerebellar vermis, and enlarged ventricles. Our group has demonstrated that late-life depression patients have increased MRI lesions in the fronto-parietal white matter and subcortical gray; and, have lesions in the caudate increase the risk of delirium with ECT and antidepressants. In the last year, we have developed high resolution MR proton spectroscopy methods to measure the concentration of a variety of physico-chemical moieties, including choline, lactic acid, water, glucose, N-acetylaspartate and glutamate in volumes of < one ml. We are utilizing this technique to study affective disorder, Alzheimer's disease and social phobia and the effect of psychotropic medications on these parameters. In an initial study, a state dependent increase in choline in depressed patients has been demonstrated; and, in Alzheimer's disease, a reduction in N-acetyl asparatate and an increase in Inositol which progresses as the disease advances. In addition, we are examining the relationship between fluoxetine concentrations in the brain using MRS and therapeutic efficacy. We currently use MR methods to assess drug efficacy in various disorders and in the development of new drugs. We have developed protocols to compare drugs developed for Alzheimer's disease based on their known effects on MRS parameters in dogs.
Current Appointments & Affiliations
Education, Training & Certifications
University of Madras (India) ·