Subarachnoid hemorrhage from spontaneous dissection of the anterior cerebral artery.

1 Takahashi S, Suga T, Kawata Y, Sakamoto K: Anterior choroidal artery: angiographic analysis of variants and anomalies. AJNR Am J Neuroradiol 1990; 11: 719–729. 2 Takahashi M, Arii H, Tamakawa Y: Anomalous arterial supply of temporal and occipital lobes by anterior choroidal artery: angiographic study. AJNR Am J Neuroradiol 1980; 1: 537–540. 3 Von Mitterwallner F: Variationsstatistische Untersuchungen an den basalen Hirngefaessen. Acta Anat (Basel) 1955; 24: 51–87. 4 Chen C, Barkovich AJ: A hyperplastic anterior choroidal artery with double persistent anastamotic channels. AJNR Am J Neuroradiol 1998; 19: 1758–1760. 5 Buxton PJ, Cook PL: Anomalous origin of the parieto-occipital artery: case note. Neuroradiology 1993; 35: 212. 6 Furuno M, Yamakawa N, Okada M, Waga S: Anomalous origin of the calcarine artery. Neuroradiology 1995; 37: 658. 7 Blackburn IW: Anomalies of the encephalic arteries among the insane. J Comp Neurol Psychol 1907; 17: 493–517. Max Wintermark, University of California, San Francisco Department of Radiology, Neuroradiology Section 505 Parnassus Avenue, Box 0628 San Francisco, CA 94143-0628 (USA) Tel. +1 415 353 1639, Fax +1 415 353 8593 E-Mail [email protected] Fig. 4. a Type 3 Takahashi anomaly. A hyperplastic AChorA supplies the parietooccipital and calcarine branches, while the PCA proper gives rise to the temporal branches. b Type 4 Takahashi anomaly. The PCA territory is almost completely fed by a hyperplastic AChorA arising from the ICA.