Magnetic resonance angiographic investigation of azygous alias monkey type anterior cerebral artery – Incidence and clinical significance

Abstract

IntroductionAzygous anterior cerebral artery (ACA) is one of the extremely rare variant occuring in the A2 segment of ACA, where the bilateral A1 segments unite together to form a single midline trunk. This trunk supplies both ACA territories. It has been also referred to as the unpaired pericallosal stem artery, unpaired anterior cerebral artery, common anterior cerebral trunk and azygos pericallosal artery. Method1.5 T (GE OPTIMA MR 360) was used for obtaining the angiographs, 114 MRA were reviewed, 90 male and 24 female, aged between 20 and 75 years. ResultThe Azygous type anterior cerebral artery was present in (3.5%), in (1.75%) a long trunk depicting the classical Azygous anterior cerebral artery was present, while in (1.75%) a short median stem was present. DiscussionThis type of presentation is a risk factor for development of aneurysm in distal part of ACA due to alteration of hemodynamics, sometimes this variation may be associated with vascular or nonvascular neurological anomalies like arteriovenous malformations, defects of septum pellucidm, Holoprosencephaly, meningomyelocele.