Gray and white matter brain abnormalities in first-episode schizophrenia inferred from magnetization transfer imaging

Background: Neuroimaging studies suggest that schizophrenia is associated with gray and possibly white matter changes. It is unclear whether these changes are present at illness onset or which brain structures are selectively affected. New imaging methods such as magnetization transfer imaging may be more sensitive than conventional volumetric imaging to the subtle structural brain changes in schizophrenia. Methods: High-resolution volumetric T1-weighted images and magnetization transfer images were acquired from 30 patients (29 with first-episode schizophrenia and 1 with schizophreniform psychoses) and 30 control subjects. Images were processed using voxel-based morphometry, which allows whole-brain analysis. Results: Compared with controls, the magnetization transfer ratio (an index of signal loss derived from magnetization transfer imaging) was reduced bilaterally in the medial prefrontal cortex (right greater than left) 1 insula (left greater than right), and white matter incorporating the fasciculus uncinatus (left greater than right) in the patient group. Analysis of the T1-weighted images did not reveal significant volumetric differences between patients and controls. Conclusions: Gray and white matter abnormalities are present in schizophrenia at illness onset. The magnetization transfer ratio is sensitive to these abnormalities, which cannot be explained by detectable atrophy in our patient group.