Intrasellar intercarotid communicating artery associated with agenesis of the right internal carotid artery: case report.

A 54-year-old man with a right hemiparesis was found to have an intrasellar intercarotid communicating artery associated with agenesis of the right internal carotid artery. Magnetic resonance imaging (MRI) studies demonstrated the spatial relationship of the anomalous artery to the surrounding structures, thus suggesting an embryonic enlargement of the capsular artery as a source of this anomalous artery.