White-Matter Microstructural Changes in Functional Dyspepsia: A Diffusion Tensor Imaging Study

OBJECTIVES: Recent neuroimaging studies have identified brain microstructural changes in patients with functional gastrointestinal disorders, especially in irritable bowel syndrome. However, whether the microstructure is changed in patients with postprandial distress syndrome (PDS) remains elusive. Therefore, the present study was aimed to examine the white-matter (WM) microstructural changes in patients with PDS. METHODS: Diffusion tensor imaging (DTI) was performed on 36 PDS patients recruited according to the Rome III criteria and 36 healthy controls. Tract-based spatial statistics were adopted to examine the between-group differences in DTI measures including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity (RD). The correlations between DTI measures and clinical variables were evaluated using a non-parametric permutation-based test. Multiple comparisons were corrected using the threshold-free cluster enhancement method. RESULTS: The patient group showed increased FA along with reduced MD and RD in multiple WM tracts, including the corona radiata, internal capsule, posterior thalamic radiation, corpus callosum, external capsule, sagittal stratum, and superior longitudinal fasciculus (P < 0.05, corrected). The inclusion of anxiety and depression as covariates abolished the between-group difference in these tracts with the exception of the corona radiata. The DTI measures were not found to be correlated with the severity of symptoms or the duration of disease (P > 0.05, corrected). CONCLUSIONS: Our findings have provided preliminary evidence of WM microstructural changes in patients with PDS. Part of the changes could be accounted for by a higher level of psychosocial distress in the patient group. Am J Gastroenterol 2013; 108: 260-269; doi: 10.1038/ajg.2012.405; published online 11 December 2012