Twig-like middle cerebral artery: a case report and literature review.

Background: Twig-like middle cerebral artery (T-MCA) is a rare cerebrovascular malformation with an incidence of approximately 0.11% to 1.17%. It is challenging to distinguish T-MCA from Moyamoya Angiopathy (MMA), particularly from unilateral MMA. Case presentation: A middle-aged female patient was admitted to our hospital for diagnosis and treatment due to intermittent dizziness lasting for two months. Neurological examination upon admission revealed no significant abnormalities.Whole-brain angiography showed clear blood flow in the left common carotid artery and internal carotid artery; however, no main trunk of the distal left middle cerebral artery M1 segment was visualized, and a network of small arteries supplying blood was observed. High-resolution intracranial arterial plaque imaging revealed no visualization of the LM1 main trunk on plain scan or enhanced high-resolution black-blood sequence; the proximal segment showed significant narrowing with circumferential thickening of the vessel wall. The patient was ultimately diagnosed with left-sided T-MCA. Conclusions: Asymptomatic T-MCA is challenging to identify clinically, making it essential to perform DSA or high-resolution MRI for suspected cases promptly. Regular follow-up is also necessary to confirm the final diagnosis in these patients.