DTI study of corpus callosum in schizophrenia patients with different treatment response

Abstract

Objective To compare the white matter fiber integrity of corpus callosum in schizophrenia patients with different treatment response with normal controls. And to explore the relationship between DTI index and the severity of the clinical symptoms in patients with schizophrenia. Methods Nineteen patients with treatment⁃resistant schizophrenia, 19 patients with treatment⁃responsive schizophrenia and 25 healthy controls were recruited from December 2012 to March 2016 of The Affiliated Brain Hospital of Nanjing Medical University. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) values of the genu, body and splenium of corpus callosum were obtained by DTI. One⁃way ANOVA was used to compare the differences in FA, AD, RD and MD values of the corpus callosum subregions among 3 groups of subjects, and Pearson correlation and partial correlation analyses were performed between FA, AD, RD, MD values and the Positive and Negative Syndrome Scale (PANSS) total score, positive symptom score, negative symptom score and general psychopathology score. Results There were significant differences in FA value of genu (F=3.139, P=0.050), FA value of splenium (F=3.531, P=0.036), AD value of splenium (F=5.261, P=0.006), RD value of splenium (F=7.161, P=0.002) and MD value of splenium (F=8.229, P=0.001) of the corpus callosum among 3 groups. Pairwise comparison showed the FA value of the corpus callosum in the treatment⁃resistant schizophrenia patients was lower than that of the control group (t=⁃2.488, P=0.016), and the FA value of the corpus callosum splenium in the treatment⁃responsive schizophrenia patients was lower than that of the control group (t=⁃2.491, P=0.016). The AD value of the corpus callosum splenium in the treatment⁃responsive schizophrenia patients was higher than that of the treatment⁃resistant schizophrenia group (t=⁃2.078, P=0.042) and the control group (t=3.334, P=0.001); the RD value of the corpus callosum splenium in the treatment⁃resistant schizophrenia patients (t=2.361, P=0.022) and treatment⁃responsive schizophrenia patients (t=3.687, P=0.000) were higher than that of the control group; the MD value of corpus callosum splenium in the treatment⁃resistant schizophrenia patients (t=2.083, P=0.041) and treatment⁃responsive schizophrenia patients (t=4.039, P=0.000) were higher than that of the control group. Partial correlation analysis results showed that, in the genu of the corpus callosum in patients with treatment⁃resistant schizophrenia, FA value was positively correlated with general psychopathological score (r=0.651, P=0.016); AD value was negatively correlated with positive symptom score (r=⁃0.553, P=0.050); RD value was negatively correlated with PANSS total score (r=⁃0.645, P=0.017), positive symptom score (r=⁃0.568, P=0.043) and general psychopathology score (r=⁃0.647, P=0.011); MD value was negatively correlated with positive symptom score (r=⁃0.640, P=0.018). In splenium of corpus callosum in treatment⁃resistant schizophrenia patients, AD value was negatively correlated with positive symptom score (r=⁃0.639, P=0.019), and positively correlated with negative symptom score (r=0.686, P=0.010). There was no correlation between FA, AD, RD and MD values of genu, body and splenium of corpus callosum and PANSS total score, positive symptom score, negative symptom score and general psychopathology score in patients with treatment⁃responsive schizophrenia (P＞0.05, for all). Conclusions Patients with treatment⁃resistant schizophrenia have more severe clinical symptoms involving more neurobiological bases. The corpus callosum injury can be used as an imaging marker of treatment response in schizophrenia.

Keywords

• schizophrenia
• corpus callosum
• diffusion tensor imaging