RESUMO
BACKGROUND: It has recently been suggested that new imaging methods such as magnetization transfer imaging (MTI) may play an important role in detecting subtle gray- and white-matter abnormalities in schizophrenia. The aim of the study was to investigate whether MTI, analyzed on a voxel-by-voxel basis, could identify areas of abnormal magnetization transfer ratio (MTR) in patients with schizophrenia. MATERIAL/METHODS: Twenty schizophrenic patients and 23 healthy controls matched for handedness and demographic variables underwent MTI and T1-weighted structural MRI in a 3-tesla scanner. Post-processing was performed with SPM99 and included co-registration of the MT-weighted and non-MT-weighted images, calculation of the MTR maps, spatial normalization, and smoothing. Differences in the MTR maps between groups were assessed using two-sample t-tests. Significant changes in MTR were detected at an individual voxel threshold of p < 0.05. RESULTS: Group comparisons revealed no significant MTR changes, although there was a trend towards MTR reduction in the left superior temporal gyrus, in the right occipital cortex, and left periventricular white matter in patients compared with controls prior to correction for multiple comparisons (p < 0.001, uncorrected). CONCLUSIONS: MTI and voxel-by-voxel statistical analysis used in the study failed to identify regions of significant MTR reductions in schizophrenic patients. Our results disagree with findings of widespread MTR abnormalities reported in recent literature.
