Hyperplastic Anterior Choroidal Artery-A Rare Variant Detected on MR Angiography

Introduction  The anterior choroidal artery is a branch of the terminal internal carotid artery (ICA) that is often an incidentally detected anomaly. The hyperplastic variant has been linked with an increased risk of aneurysms. We explore the role of magnetic resonance (MR) angiography in the detection of this variant and its impact of presentation of patients. Patient Presentation  A 62-year-old diabetic and hypertensive male came to the casualty with complaints of giddiness, left-sided weakness, and loss of coordination for the last 2 to 3 days. He was provisionally diagnosed with a posterior circulation stroke. Management and Outcome  Magnetic resonance imaging of brain revealed an acute infarct in the right thalamus and the midbrain. Time-of-flight angiography sequences were done that showed hypoplasia of the A1 segment of the left anterior cerebral artery, fetal origin of the right posterior cerebral artery, narrowing of the left ICA, and a hyperplastic left anterior choroidal artery. He was managed conservatively with antiplatelets. He later underwent a digital subtraction angiography that revealed significant narrowing of the left ICA for which he was advised carotid stenting. However, the patient was unwilling for the procedure and was discharged on oral medication with stable vitals. Conclusion  Anatomical variations in the intracranial vasculature impact ischemia territory and the approach to intracranial pathology. Hyperplastic anterior choroidal artery results from the abnormal persistence of fetal pattern of vascular supply. It is important to recognize the presence of a hyperplastic anterior choroidal artery as it impacts both disease presentation and management of these patients. MR angiography allows for noninvasive and reliable detection of these anomalies in patients without the risks associated with radiation or contrast exposure in conventional/computed tomography angiography.