Association of Corticospinal Tract Asymmetry With Ambulatory Ability After Intracerebral Hemorrhage

Background Ambulatory ability after intracerebral hemorrhage (ICH) is important to patients. We tested whether asymmetry between ipsi‐ and contra‐lesional corticospinal tracts (CSTs) assessed by diffusion tensor imaging (DTI) is associated with post‐ICH ambulation. Methods Patients with spontaneous supratentorial ICH were recruited from 8 US sites between 2017 and 2024. For each patient, fractional anisotropy (FA) asymmetry index (AI) was computed for the whole CST and on a subset of fibers restricted to the cerebral peduncle (CP). Clinical and radiographic features were collected. The primary outcome was Barthel Index Mobility Score (BIMS) at 3 months (dichotomized outcome [DO]: BIMS 15 = good [independent ambulation]; BIMS < 15 = poor [non‐independent ambulation]; ordinal outcome [OO]: BIMS 0, 5, 10, 15). Two imputation‐based multiple logistic regression analyses accounted for whether ICH prevented tracking of CSTs. Odds ratios (ORs) were reported for a change of 0.1 and 95% confidence intervals (CIs). Results At 3 months, 124 patients were eligible for inclusion. In addition to known clinical variables, CST and CP FA AI were associated with poor BIMS (OR 2.97, CI 1.12–7.90, p = 0.029; OR 3.80, CI 1.63–8.84, p = 0.002). In Model 1, unresolved FA (FA zero) was not correlated with lower BIMS (DO: OR 3.25, CI 0.62–17.07, p = 0.163; ordinal outcomes: OR 2.02, CI 0.48–8.55, p = 0.341). In Model 2, the combination of CST FA AI and FA zero correlated with lower BIMS (DO: joint p ‐value =0.041; OO: p = 0.030). CP FA asymmetry was associated with lower BIMS (DO: OR 3.96, CI 1.25–12.55, p = 0.019; OO: OR 3.39, CI 1.24–9.27, p = 0.017). Conclusion DTI‐assessed CST integrity may be an additional tool physicians can utilize to guide post‐ICH ambulatory expectations.