Acute basilar artery occlusion: topographic study of infarcts.

OBJECTIVE: To determine the ischemic lesions distribution and extension of patients with basilar artery thrombosis by the means of magnetic resonance imaging (MRI).

METHODS: In 17 patients with thrombosis of the basilar artery, MRI was performed, including T2-weighted, magnetic resonance angiography (MRA) and diffusion-weighted imaging (DWI) sequences in the short-term phase (<48 hours). The shapes of ischemic lesions were obtained by graphic software and overlapped on a representative layer outline background.

RESULTS: The MRA showed basilar artery occlusion in all cases and the DWI revealed different patterns of ischemic lesions. Most patients showed multiple lesions within the posterior circulation territory. Lesions more often occurred in pontes, cerebellums and mesencephalons than medullas, thalami and occipital lobes. Basilar pons, cerebral crus and cerebellum hemisphere were more susceptible than pontine tegmentum, vermis, midbrain tegmentum and tectum.

CONCLUSIONS: When the basilar artery is occluded, basilar pons, cerebral crus and cerebellum hemisphere were most susceptible. The branches with smaller lumen of basilar artery, which are easier to be affected, are thought to be the cause of such a phenomenon.