Abstract Details

The APOE ?4 allele is a risk factor for Alzheimer's disease and cardiovascular disease. Cortical thinning patterns have been described in many neurodegenerative diseases and used both for diagnosis and disease monitoring. The imaging signatures of post-stroke and vascular cognitive impairment have not been well described. We investigated associations between regional cortical thinning and APOE-?4 carrier status in stroke survivors.

We compared regional cortical thickness in apolipoprotein E (APOE) ?4 carriers and non-carriers in ischemic stroke survivors at 3 years follow-up.

Seventeen APOE-?4 carriers and 70 non-carriers with 1-mm isotropic T1-weighted MRI available at 3 years post-stroke were included from the Cognition And Neocortical Volume After Stroke (CANVAS) study. We used a mixed-effect model with within-subject random intercept to compare vertex-wise surface-based cortical thickness between the APOE groups after adjusting for age and sex. Cortical thicknesses on ipsilateral and contralateral hemispheres were estimated using longitudinal FreeSurfer (version 6) cortical reconstruction and volumetric segmentation according to the ‘Desikan-Killiany' parcellation atlas. Inaccuracies in pial surfaces from FreeSurfer segmentations were corrected manually and infarcted vertices were excluded from cortical thickness maps using binary stroke lesion masks traced a-priori. Family-wise correction for multiple comparisons was completed using a 5% two-stage adaptable FDR.

APOE-?4 carriers and non-carriers did not differ on age, sex, or years of education, Charlson comorbidity index, hypertension and Type 2 diabetes mellitus history, stroke severity, location, or Oxfordshire classification, or white matter hyperintensity volume. More participants had right strokes in both groups.

We found significantly lower cortical thickness in the right ipsilateral precentral cortex in the APOE-?4 carriers compared non-carriers (p < 0.0001). Further adjustment by participant’s cognitive status (cognitively impaired vs cognitively normal) did not change the results.

APOE-?4 is associated with increased precentral cortical thinning at 3 years post ischemic stroke.