A fetal circle of Willis is associated with a decreased deep white matter lesion load.

Abstract

To investigate the relationship between morphologic differences in the circle of Willis and the presence and location of white matter lesions (WMLs). Two hundred forty-three consecutive patients with clinical manifestations of atherosclerotic disease underwent MRI of the brain and MR angiography of the circle of Willis. Subjects with a fetal configuration of the circle of Willis demonstrated a decreased load of small (p < 0.01) and medium (p < 0.01) deep WMLs compared with subjects with a nonfetal configuration of the posterior part of the circle of Willis. A fetal configuration of the posterior part of the circle of Willis may be an important protecting determinant in the etiology of white matter lesions.