Abnormalities in White Matter Integrity in First Episode Schizophrenia Using Atlas-Based SegmentationA. LaVenture, S. Lee, T. Asami, P. Pelavin, L. Seidman, J. Goldstein, G. Mesholam, R. McCarley, M. E. Shenton, M. Kubicki
Mysell Harvard Research Day, Psychiatry Annual Meeting
Introduction:Atlas-based segmentation can be useful in detecting and localizing white matter abnormalities in patients with schizophrenia. This study examines white matter abnormalities in first episode schizophrenia compared with healthy controls. We used white matter atlas-based segmentation to identify structures, then calculated Fractional Anisotropy (FA) and Trace, and lastly correlated our findings with symptom severity. Symptom severity was assessed with the Brief Psychiatric Rating Scale (BPRS).
Methods:Seventeen first-episode patients with schizophrenia and seventeenage and gender matched healthy controls were scanned and received neuropsychological evaluatio. The Montreal Neurological Institute (MNI-152) White Matter Atlas, and the ICBMDTI-81 Atlas were used to define regions of interest (Mori et al.,2005). Fractional Anisotropy (FA) and trace were compared between the two groups. DTI Image Aquisistion: Diffusion data were acquired on a 3Tesla GE Echo speed system (General Electric Medical Systems, Milwaukee,WI). Diffusion-weighted images were acquired using an echo planar imaging sequence, 51 diffusion directions, and 1.7 *1.7*1.7 mm resolution.
Results:Patients with first-episode schizophrenia showed lower FA values in the genu and splenium of corpus callosum, the internal capsule, the fornix, bilateral uncinate fasciculi and the left inferior fronto-occipital fasciculus compared with healthy volunteers (see Figure 2 and Table 1 below). Spearman correlation analysis demonstrated that only FA values in the right inferior fronto-occipital fasciculus were significantly correlated with the BPRSscores, and, more specifically, to negative symptom scores in first episode schizophrenia (see Figure 3). In terms of trace, increased diffusivity was shown in almost all white matter regions (see Figure 4). Spearman correlation analysis showed that only trace values in the left cingulum were significantly correlated with BPRS total scores in first episoe schizophrenia (see Figure 3).