Fronto-temporal connectivity in never-medicated patients with first-episode schizophrenia: A DTI study

Abstract

Purpose: To assess fronto-temporal connectivity in never-medicated patients with first episode schizophrenia (FES). Material and methods: Twelve never-medicated patients (median age = 25.5 y) with first episode schizophrenia (according to DSM-IV system) and sixteen demographically matched controls were enrolled in the study. Conventional MRI sequences were obtained. Single shot echo-planar DTI was acquired in 32 non-collinear directions. Tractography of the direct pathway of the superior longitudinal fasciculus (SLFd) and uncinate fasciculus of both hemispheres was performed, and ROIs at the anterior cingulum and external capsule of both hemispheres were drawn. Fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD) and Trace of the ROIs and reconstructed tracts were calculated. Group comparison was performed using independent sample t-test and Fisher’s exact test. Results: Compared to healthy participants, there was significant reduction of FA of the left external capsule (p = 0.001) with increase in RD and Trace (p = .004, .048 respectively). However, the right SLFd showed significant reduction of AD (p = 0.005) and the left SLFd showed significant reduction of its volume (p = 0.02). Conclusion: In patients with FES, impaired white matter connectivity was recognized in the right SLFd and left external capsule associated with reduction in the volume of the left SLFd.

Keywords

• First episode schizophrenia
• DTI
• Axial and Radial diffusivity
• Superior longitudinal fasciculus
• External capsule