OBJECTIVE: This study examined how different diffusion tensor imaging (DTI) acquisition planes affect diffusion tensor indices in multiple sclerosis (MS) patients, stratified by optic neuritis (ON) history. MATERIALS AND METHODS: Thirty-seven relapsing-remitting MS patients were prospectively enrolled: 20 with a history of ON (MSwON) and 17 without (MSwoON). Each participant underwent DTI in both axial and coronal planes using a 1.5 Tesla MRI system. Optic nerve regions of interest were drawn independently for each plane, and 18 DTI-derived parameters were compared between groups using linear mixed-effects models with False Discovery Rate correction. RESULTS: > 0.05), suggesting that diffusion metrics were broadly comparable between MSwON and MSwoON patients. The group × acquisition plane interaction was also non-significant across all parameters. In contrast, acquisition plane exerted a significant main effect on ten parameters following FDR correction - among them Fractional Anisotropy, Apparent Diffusion Coefficient, Mean Diffusivity, and Radial Diffusivity - with axial acquisitions consistently yielding higher diffusivity and anisotropy values than coronal ones. CONCLUSION: Optic nerve DTI parameters did not differ significantly between MSwON and MSwoON patients, a finding compatible with subclinical bilateral nerve involvement in both groups. The marked dependence of multiple DTI metrics on acquisition plane points to the non-negligible role of imaging geometry, EPI-related distortions, and partial volume contamination in small-structure DTI measurements.
Baykara et al. (2026) studied this question.