Twig-like middle cerebral arteries: Clinical and radiological findings

Aplastic or twig-like middle cerebral artery (MCA) is a rare vascular anomaly characterized by replacement of the M1 segment by a plexiform network of small vessels. Though rare, familiarity with this entity and ability to differentiate it from radiological mimics such as moyamoya changes and steno-occlusive diseases are important. We review the clinical and radiological manifestations of patients diagnosed with twig-like MCA on cerebral angiograms over a five-year period.

Retrospective review of all patients diagnosed with twig-like MCA on cerebral angiograms was performed from January 2015 to January 2020. This was the inclusion criterion for this retrospective study. For each patient, demographic data, clinical presentation, imaging findings and management strategies were reviewed.

Between January 2015 and January 2020, three patients with twig-like MCA were identified from 657 patients who underwent four-vessel diagnostic cerebral angiograms (0.45%). In all three cases, the involvement was unilateral (two left-sided and one right- sided). Two patients were male, and one was female. Patients ages were 25, 26 and 46 years. Two of the three patients presented with headache and the third patient with pulsatile tinnitus. There were otherwise no ischemic or hemorrhagic changes. No other vascular anomaly was identified. Twig-like MCA is a rare anatomical variant in which a plexiform network of small vessels replaces the M1 segment of the MCA. Accurate diagnosis and distinguishing this entity from radiological mimics such as moyamoya and steno-occlusive diseases are important for appropriate management and to prevent unnecessary investigations.