A Study on Branching Pattern of Middle Cerebral Artery and its Variations: A Systematic Review and Meta-analysis

Middle cerebral artery (MCA) anatomy is essential to prevent catastrophe during intravascular procedures such as thrombolysis and cerebral angiography and neurosurgical practices, example - stent insertion, bypass grafting, etc. Eighty percent of blood supply to the brain is through MCA. The motor and sensory homunculus of brain representing arm and face receive blood supply from MCA. MCA consists of four segments. M1 is between the origin of MCA and the genu of insula (sphenoidal); M2 runs from limen insula to insula's circular sulcu (insular) s; M3 from circular sulcus to Sylvian fissure surface (opercular). Cortical branches of MCA territory can be divided into 13 areas orbitofrontal, prefrontal, precentral, central, postcentral, anterior parietal, posterior parietal, angular, temporo-occipital, posterior temporal, middle temporal, anterior temporal, and temporopolar arteries. MCA with bifurcated termination is seen in 64.70%. Bilateral bifurcation of MCA is present in 50%. Unilateral bifurcation of MCA is present in 25.45% on the left side and in 24.54% on the right side. MCA with trifurcated termination is seen in 12.35%. Bilateral trifurcation is present in 14.28%. Unilateral trifurcation is seen in 28.57% on the left side and 57.14% on the right side. Quadrifurcated type of termination is seen in 2.35%, four on the right side and four on the left side. Different sites of accessory MCA are at the level of proximal A1, at the level of middle A1, at the level of distal A1, at the level of Anterior communicating artery (AComA) at the level of A2. M1 segment (sphenoidal) of MCA is either straight or curved, where it is more curved than straight. The volume of this segment is more on the left side in males as compared to females. Average length of M1 segment is 17.30 ± 0.07 mm. Length is more on the left side as compared to the right side; it is more on nonaneurysmal side as compared to aneurysmal side. Again, the average diameter of M1 segment of MCA is 2.37 ± 0.33 mm, which is more on the left side and in male populations, diameter is more on aneurysmal side as compared to nonaneurysmal side. Diameter of M2 segment is more on left side (0.8-2.6 mm), and it is also more in case of females as compared to males. The M3 segment has been found to be more on the left side (1.5 mm as compared to right side1.4 mm. MCA fenestration is the name given to a fusion defect in the main trunk of the MCA after its origin, such that it emerges as a single trunk, branches, and then re-fuses. CRD number-420251052884.