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The Anterior Inferior Cerebellar Artery: Its Radiographic Anatomy and Significance in the Diagnosis of Extra-axial Tumors of the Posterior Fossa

1968; Radiological Society of North America; Volume: 90; Issue: 2 Linguagem: Inglês

10.1148/90.2.281

1527-1315

Mutsumasa Takahashi, Gabriel H. Wilson, William N. Hanafee,

Glioma Diagnosis and Treatment

The anterior inferior cerebellar artery traverses the cerebellopontine angle cistern in close association with the seventh and eighth cranial nerves and supplies the lower pons, medulla, and anterior portion of the cerebellum. In spite of the known anatomic relationships of this artery, angiographic diagnosis of cerebellopontine angle tumors has depended upon presence of tumor vessels (4, 7, 11, 14, 18), superior displacement of the superior cerebellar artery (5, 8, 11, 13), and displacement or obliteration of the petrosal veins (5, 15). This is in part due to the fact that lateral and half-axial projections routinely obtained during vertebral angiography are not suitable for visualization of the anterior inferior cerebellar artery. It has been our practice to obtain straight anteroposterior roentgenograms which permit visualization of the anterior inferior cerebellar artery with the use of the subtraction technic (6). In a review of 250 catheter vertebral angiograms on 227 patients there were 9 cases with cerebellopontine angle and clivus tumors in which displacement or stretching of the anterior inferior cerebellar artery was demonstrated. The purpose of this report is to stress the importance of this artery for differentiation between intra-axial and extra-axial tumors in the posterior fossa. Anatomy The anterior inferior cerebellar arteries usually originate from each side of the basilar artery about 1 cm above the junction of the two vertebral arteries and course laterally, crossing the eighth cranial nerve within the cerebellopontine angle cistern. The artery gives off the internal auditory artery which passes immediately into the internal auditory meatus. The internal auditory artery may arise directly from the basilar artery slightly above the origin of the anterior inferior cerebellar artery (16). After giving off the internal auditory artery, the anterior inferior cerebellar artery divides into two major branches within the cerebellopontine angle cistern (2). The lateral branch courses laterally toward the superior and inferior semilunar lobules of the cerebellum and anastomoses with the branches of the superior cerebellar and posterior inferior cerebellar arteries. This lateral branch curls around the flocculus, giving the appearance of a loop. Small branches arising from the proximal portion of the lateral branch contribute to the blood supply of the middle cerebellar peduncle and adjoining part of the pons (2). The medial branch courses downward toward the biventral lobule and anastomoses with the branches of the posterior inferior cerebellar artery. The restiform body is also supplied by the small branches originating from the proximal portion of the medial branch (1, 2). Many variations of the anterior inferior cerebellar artery have been observed in association with the anomalies of the posterior inferior cerebellar artery (2, 9, 18). Variations of the two arteries are the rule rather than the exception.