Boundary-anchored thalamic ADC profiling shows spatially structured abnormalities in multiple sclerosis.

PURPOSE: Diffusion MRI is sensitive to tissue abnormalities in multiple sclerosis (MS), but conventional region-of-interest measures reduce spatially structured signal patterns to a single summary value. We evaluated boundary-anchored thalamic apparent diffusion coefficient (ADC) profiling in MS using line-based edge-anchored profiling (LEAP).

MATERIALS AND

METHODS

In this retrospective matched-control study, age- and sex-matched controls (CTRL, n = 28) and participants with relapsing-remitting MS (RRMS, n = 14) or secondary progressive MS (SPMS, n = 14) were analyzed on the same 3T MRI scanner using the same diffusion protocol. LEAP was applied bilaterally at the medial thalamic surface adjacent to the third ventricle. Participant-averaged bilateral summary metrics and exploratory side-specific profile-shape metrics were derived from ADC curves.

RESULTS

The clearest signal was observed in comparisons between MS and matched controls, with the largest number of differences seen for SPMS versus controls. Compared with controls, SPMS showed a higher ventricle-near mean ADC (p = 0.004), higher profile maximum ADC (p = 0.003), and a steeper early profile slope (p = 0.005). RRMS generally showed intermediate values. Direct RRMS-versus-SPMS comparisons of bilateral summary metrics were limited. Exploratory right-sided profile-shape metrics and left-right asymmetry measures suggested possible phenotype-related differences.

CONCLUSION

Boundary-anchored thalamic ADC profiling detected spatially structured abnormalities in MS relative to matched controls, with the strongest deviation in SPMS. Exploratory shape-based findings should be considered hypothesis-generating and suggest additional profile-level information beyond bilateral summary values.

KEY POINTS: · LEAP enables spatially resolved thalamic ADC assessment.. · SPMS showed strongest deviations from matched controls.. · RRMS demonstrated intermediate profile characteristics.. · Profile morphology contained information beyond bilateral averages.. · Boundary-anchored profiling complements conventional ROI analysis..

CITATION FORMAT: · Garner M, Fries F, Garner C et al. Boundary-anchored thalamic ADC profiling shows spatially structured abnormalities in multiple sclerosis. Rofo 2026; DOI 10.1055/a-2941-6690.