This study presents a new method to differentiate brain white matter hyperintensity (WMH) severity using conventional T1-weighted and T2-weighted MRI. By combining normalized image intensity, heterogeneous tissue properties within lesions are revealed. Lesion severity is quantified through two distance measures of parallel and perpendicular deviation from normal appearing white matter. Correlations with diffusion imaging based measures suggest that multi-modal voxel-based lesion analysis provide comparable but high-resolution tissue information. Based on conventional MRI scans this method adds valuable insight into the differentiated impact of WMH lesions on brain structure and function.