Magnetic resonance imaging of fixed post mortem brains reliably reflects subcortical vascular pathology of frontal, parietal and occipital white matter

Aims: Subcortical vascular pathology of the white and deep grey matter (WM and DGM) is associated with cognitive impairment. Routine neuropathological assessment of subcortical vascular pathology is based on semiquantitative scoring of characteristic lesions in a limited number of histological slides from selected WM and DGM areas. Clinically, WM and DGM lesions are visualized as hyper-intensities on magnetic resonance imaging (MRI). The aim of this study was to evaluate the feasibility of MRI on fixed post mortem brain hemispheres to complement routine neuropathological assessment of subcortical vascular pathology.

Methods: We assessed subcortical vascular pathology in 40 post mortem brain hemispheres from demented (n = 26) and nondemented (n = 14) individuals (mean age 83.2 ± 14.8 years; 62.5% female) using (i) routine histological assessment; (ii) extensive histological assessment of the entire hemisphere at 7-mm intervals; and (iii) full T2-weighted MRI performed on fixed post mortem brain hemispheres.

Results: In both WM and DGM routine histological scores for subcortical vascular pathology were significantly lower (P < 0.01) than the corresponding scores obtained by extensive histological assessment. In contrast, no significant differences were seen between scores obtained by MRI and extensive histological assessment in frontal, parietal and occipital lobes while MRI scores were significantly lower in the temporal WM and DGM (P < 0.01).

Conclusions: The results of our study indicate that routine histological assessment underrates subcortical vascular pathology and we conclude that MRI could be used in addition to complement neuropathological post mortem assessment of subcortical vascular pathology of the WM.