Brain morphometry using diffusion-weighted magnetic resonance imaging: application to schizophrenia

Abstract

Loss of cortical gray matter is accompanied by a commensurate increase in the sulcal and intraventricular cerebrospinal fluid volume. On diffusion-weighted magnetic resonance imaging, this would be reflected as a higher apparent diffusion coefficient in affected brain regions. On the basis of the above premise, we suggest that the apparent diffusion coefficient may be used as a surrogate marker for the assessment of regional brain volume deficits. We demonstrate this approach by voxelwise analysis of registered apparent diffusion coefficient images from a group of 15 patients with schizophrenia and 15 age-matched healthy controls. We found widespread regional apparent diffusion coefficient increases in patients. Affected areas included the bilateral insular cortex, hippocampus, temporal lobe, and occipital areas. These results largely concur with previous findings of cortical volume deficits in schizophrenia.

Fig. 1

Regions where the patient group had a significantly (p<0.01, cluster size >200 mm³) higher apparent diffusion coefficient (ADC) than the control group are shown in blue superimposed on the average interparticipant registered magnetization-prepared rapid gradient echo images from all 30 participants.(a) Bilateral insular cortex. (b) Bilateral hippocampus. (c) Bilateral superior and middle temporal gyri. (d) Bilateral posterior part of the inferior temporal gyrus, with somewhat larger affected region on the left. (e) Several bilateral regions on the occipital lobe including the calcarine cortex, lingual gyrus, cuneus, and middle occipital gyrus. The region highlighted in yellow is the only significant cluster in which controls had increased ADC. (f) The lateral ventricles.