MR study on white matter injury in patients with acute diquat poisoning.

Objective: To explore the microstructural damage of white matter in acute diquat (DQ) poisoning patients using diffusion kurtosis imaging (DKI) and Tract-based Spatial Statistics (TBSS).

Methods: This study included 19 DQ poisoning patients and 19 age-matched controls. MRI was performed using a 3.0 T Philips Achieva scanner with sequences including 3D T1WI, T2WI, DWI, 3D T2WI-FLAIR, and DKI (3 b-values, 15 directions). DICOM to NIFTI image form conversion was done using MRIcron's Dcm2niigui, followed by motion and eddy current correction with FSL to create a brain mask. Scalar indicators (MK, AK, RK, FAK) were calculated with DKE software. TBSS was used for spatial normalization, skeletonization, and projection of DKI indices for group analysis with TFCE for multiple comparison correction (P < 0.025).

Results: After the screening and enrollment process, 19 DQ-poisoned patients and 19 healthy volunteers were analyzed. No significant age or sex differences were found between groups. For Mean Kurtosis (MK), the right corticospinal tract showed a significant difference with a mean difference of 0.21 (95 % CI: 0.15-0.27) and P = 0.000503. Axial Kurtosis (AK) in the left superior longitudinal fasciculus had a mean difference of 0.18 (95 % CI: 0.12-0.24) and P = 0.0024. Fractional Anisotropy of Kurtosis (FAK) in the right corticospinal tract showed a mean difference of 0.19 (95 % CI: 0.13-0.25) and P = 0.0000318. Axial Kurtosis (AK) positively correlated with blood drug levels (r = 0.52, P < 0.05). Seven patients developed subcortical leukodystrophy, mainly in the frontal parietal lobe, with possible insular lobe involvement.

Conclusions: DQ poisoning primarily damages the right corticospinal tract, right cingulate gyrus, and left superior longitudinal fasciculus, potentially causing movement and visual impairments. The injury involves demyelination and axonal degeneration, with asymmetrical damage between hemispheres. The left superior longitudinal fasciculus injury is dose-dependent, and unlike prior studies, dopaminergic nuclei were unaffected. The frontal parietal lobe is predominantly affected, with some insular lobe involvement in DQ poisoning patients.