White Matter Hyperintensities in Alzheimer's Disease: A Lesion Probability Mapping Study

BACKGROUND/OBJECTIVE: Higher white matter hyperintensity (WMH) load has been reported in Alzheimer's disease (AD) patients in different brain regions when compared to controls. We aimed to assess possible differences of WMH spatial distribution between AD patients and age-matched controls by means of lesion probability maps.

METHODS: The present study included MRI scans of 130 probable AD patients with a mean age of 73.4±8.2 years from the Prospective Dementia Registry Austria Study and 130 age-matched healthy controls (HC) from the Austrian Stroke Prevention Family Study. Risk factors such as hypertension, diabetes mellitus, hypercholesterolemia, coronary artery disease, and smoking were assessed. Manually segmented FLAIR WMH masks were non-linearly registered to a template and voxel-based probability mapping was performed.

RESULTS: There were no significant between-group differences in cardiovascular risk factors and WMH volume. AD patients showed a significantly higher likelihood of having WMH in a bilateral periventricular distribution than controls before and after correcting for age, sex, cardiovascular risk factors, and ventricular volume (p≤0.05; threshold-free cluster enhancement corrected). There was no significant association between the periventricular WMH volume and cognitive decline of AD patients.

CONCLUSION: In AD, WMH were preferentially found in a periventricular location but the volume of lesions was unrelated to cognitive decline in our study irrespective of lesion location.