Quantification of afferent vessels shows reduced brain vascular density in subjects with leukoaraiosis

To investigate vessel density changes with increasing age in three areas of the brain and to correlate these changes with leukoaraiosis (LA) on the basis of magnetic resonance (MR) images and location in deep white matter (WM).

Internal review board approval or informed consent from next of kin was not required. Brains of 21 subjects (mean age, 72.5 years; 12 men, nine women) were evaluated at autopsy with MR imaging. The presence of LA was indicated by confluent or patchy areas of hyperintensity in deep WM. Microvascular density (percentage of vessel area divided by total area) in subjects with LA was measured with computerized morphometric analysis in LA lesions, healthy-appearing WM at MR imaging, and the cortex. These measurements were compared with each other and with measurements from corresponding areas in healthy subjects. Afferent vasculature was stained with alkaline phosphatase in celloidin sections. Hypotheses were tested with computation of a series of repeated-measures linear mixed models.

Autopsy brains from 12 subjects with LA (mean age, 72 years; six men, six women) and nine subjects without LA (mean age, 73 years; six men, three women) were studied. Afferent microvascular density +/- standard deviation in LA lesions in deep WM (2.56% +/- 1.56) was significantly lower than that in corresponding deep WM of healthy subjects (3.20% +/- 1.82) (P = .018). Subjects with LA demonstrated decreased afferent vascular density at early ages in all three areas of the brain when compared with healthy subjects of the same age.

Findings of decreased afferent vascular density in the area of LA and outside the lesion indicate that LA is a generalized cerebrovascular disease process rather than one confined to deep WM.