Role of diffusion tensor imaging to evaluate amygdala–hippocampal complex and superior temporal gyrus in treatment-resistant schizophrenia and non-treatment-resistant schizophrenia patients

Abstract Background Treatment-resistant schizophrenia (TRS) affects around 30% of schizophrenic patients. One of its important causes is functional brain abnormalities. Diffusion tensor imaging (DTI) is a non-invasive magnetic resonance imaging (MRI) technique used to assess the structural integrity of white matter in the human brain. This study aimed to compare the voxel-based differences in white matter integrity in the amygdala–hippocampal complex and superior temporal gyrus regions between treatment-resistant schizophrenia and non-treatment-resistant schizophrenia patients. Methods This prospective study was conducted in a tertiary hospital for a period of one year. Total of 13 TRS and 16 non-TRS patients were enrolled and subjected to an MRI brain study using combined DTI and 3D FLAIR sequences. Four quantitative parameters were generated during the post-processing of DTI studies, which are fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Results TRS group had significant lower FA values in the region of right AHC (0.40 vs 0.43, p value = 0.016, left AHC (0.39 vs 0.43, p value = 0.005) and right STG (0.39 vs 0.42, p value = 0.013). No significant differences were found in FA values in the region of left STG as well as MD, RD and AD values in both AHC and STG regions. Conclusion There is significant difference in FA values between TRS and non-TRS group in the region of right AHC, left AHC and right STG. This finding may reflect the pathophysiology in TRS and might provide new insight towards treatment resistance or response to antipsychotics in patients with schizophrenia.