Early Brain Volume Change After Stroke: Subgroup Analysis From the Axis-2 Trial

Objective: The timing of brain atrophy after stroke is not well understood. We investigated the associations between age and imaging features and brain volume change in the first month after stroke. Methods: We retrospectively studied patients with acute ischemic stroke enrolled in the AXIS-2 trial. Total brain volume change from hyperacute MRI data to the first month after stroke was assessed using unified segmentation in SPM12. We hypothesized that age, ischemic brain lesion size and white matter changes were associated with larger brain volume change. Enlarged perivascular spaces (EPVS) and white matter hyperintensities (WMH) were rated visually and the presence of lacunes was assessed. Results: We enrolled 173 patients with a mean age of 67±11 years, 44 % were female. There was a median 6 mL decrease in volume (25th percentile -1mL-75th percentile 21mL) over time, equivalent to a median 0.5% (IQR-0.07% - 1.4%), decrease in brain volume. Age was associated with larger brain volume loss (per 10 years of age, 5 mL 95% CI 2 mL-8 mL). Baseline DWI lesion volume was not associated with greater volume loss (per 10 mL of lesion volume, change by 0 mL (95% CI -0.1 mL-0.1mL). Increasing Fazekas scores of deep white matter hyperintensity were associated with greater tissue loss (5 mL, 95% CI 1 mL-10 mL). Brain volume change was associated with ordinal change on the modified Rankin scale at 90 days (per 10 ml, OR 1.085, 95% CI 1.031-1.141) but the association was not present when adjusting for age, baseline diffusion lesion volume and NIHSS score (OR 1.044, 95% CI 0.990-1.010).Interpretation-Global brain volume loss occurs over 1 month after stroke and is associated with age and deep white matter disease. We did not find evidence that more severe strokes lead to increased early tissue loss.