Fig 3.

Giant, partially thrombosed right vertebral dissecting aneurysm distal to the PICA origin occurring with acute compression of the brain stem in a 10-year-old boy (patient #8). A, MR imaging shows dissecting aneurysm compressing the brain stem. B,C, Right (B) and left (C) vertebral angiogram shows giant aneurysm of the right vertebral artery distal to the PICA origin. D,E, Bilateral vertebral angiograms (D) and corresponding radiograph (E) with complete coil occlusion of the aneurysm and parent vertebral segment. F, MR imaging 6 months later demonstrates shrinkage of the aneurysm with decreased compression of the brain stem.