The anterior inferior cerebellar artery in mass lesions. Preliminary findings with emphasis on the lateral projection.

Analysis of abnormalities of the configuration of the anterior inferior cerebellar artery in lateral projection facilitates diagnosis of posterior fossa masses. Cerebellopontomedullary angle lesions frequently cause arcuate posterior-inferior displacements of the rostrolateral artery or reversal of curvature of the ascending segment of the meatal loop. Vermian, hemispheric, intra-fourth ventricular, and suitably situated extra-axial masses alter the plane of the lateral loop of the caudomedial artery. Tonsillar herniation may be detected in patients with hypoplastic or absent posterior inferior cerebellar arteries by analyzing the relationship of the biventral segment of the descending or caudomedial artery to the foramen magnum.