Regional axonal abnormalities in first episode schizophrenia: preliminary evidence based on high b-value diffusion-weighted imaging.

Connectivity has been implicated as a major source of brain abnormality in schizophrenia. The current study focused on first episode schizophrenia to identify possible early pathology in axonal structure. First episode schizophrenic patients and healthy controls were scanned in a 1.5-Tesla scanner during which high b-value diffusion-weighted imaging (DWI) was acquired. Histogram analysis revealed a decrease in overall white matter (WM) tissue, indicating relative axonal abnormality in the schizophrenic group. Subsequent analysis found that this effect was contributed mainly by anterior-prefrontal bundles. Moreover, negative correlations were found between positive and negative symptom severity and whole head WM displacement peak value, implying an overall lesser degree of WM integrity is associated with greater symptom severity. These preliminary results suggest that WM abnormality, as measured by high b-value DWI, is already a significant pathological brain marker in early stage of schizophrenia.