Detection of microstructural white matter alterations in functional gastrointestinal disorders assessed by diffusion kurtosis imaging

Abstract

Background and aim: We evaluated whether diffusion kurtosis and tensor imaging (DKI/DTI) could reveal microstructural alterations in the brains of patients with functional gastrointestinal disorders (FGIDs), and whether imaging findings were correlated with health-related quality of life (HRQOL).

Methods: Twelve patients with FGIDs fulfilling the Rome IV criteria, and seven healthy controls were examined using a 3 T magnetic resonance (MR) scanner. Tract-based spatial statistics and regions of interest analyses were performed to compare the mean kurtosis (MK), fractional anisotropy (FA), and mean diffusivity (MD) between patients with FGIDs versus controls. HRQOL was assessed in patients with FGIDs using the eight-item short form of the Medical Outcome Study Questionnaire (SF-8) and the Gastrointestinal Symptom Rating Scale.

Results: Patients with FGIDs had extensive, widespread regions of reduced MD in the white matter in comparison with healthy controls, whereas no significant differences were observed in MK and FA. No significant differences in deep gray matter for the MK, FA, and MD values were observed between patients with FGIDs and controls. In patients with FGIDs, the FA values in the globus pallidus had a significant and negative correlation with SF-8 (a mental component summary) (r = -0.797, P = 0.01 uncorrected for multiple comparisons).

Conclusions: DKI/DTI can help identify microstructural white matter alterations in patients with FGIDs. The FA values in the globus pallidus may be useful for a severity assessment of FGIDs.

Keywords: diffusion kurtosis imaging; functional dyspepsia; functional gastrointestinal disorders; irritable bowel syndrome.

Figure 1

Voxelwise statistical analyses of the diffusion kurtosis and tensor maps of the white matter skeleton using tract‐based spatial statistics. Compared with healthy controls, patients with FGIDs showed significantly decreased mean diffusivity (MD) in widespread regions. Interestingly, no significant differences were observed in mean kurtosis (MK) and fractional anisotropy (FA) between the two groups. The statistical maps are overlaid on the mean FA map. Clusters that survived FWE correction of P < 0.05 with TFCE are presented as a colored area showing significant changes in the white matter skeleton. (n.s., not significant).

Figure 2

Diffusion kurtosis and tensor metrics of the deep gray matter structures in patients with FGIDs. There were no significant differences in the MK, FA, and MD values in the caudate nucleus (CN), putamen (PU), globus pallidus (GP), thalamus (TH), substantia nigra (SN), red nucleus (RN), and periaqueductal gray matter (PAG) between the groups (Mann–Whitney U test). Both the MK and FA values are unitless. () FGIDs, () control.