Neuroangiography patterns and anomalies of middle cerebral artery: A systematic review

BACKGROUND: As the largest and most complex cerebral artery, the middle cerebral artery (MCA) patterns and anomalies are not fully reported. At present, there is confusion about the criteria for the different subtypes. The study of MCA patterns and anomalies is important because variants such as accessories or duplicates represent a high risk of failure during endovascular embolization or navigation during treatment for ischemic stroke. This study conducted a systematic review of studies on the neuroangiography patterns and anomalies of MCA. METHODS: We conducted a systematic review of four articles online databases and included English articles from PubMed, the Cochrane Library, Directory of Open Access Journals, and EBSCOhost. RESULTS: The proportion of the MCA branching pattern was 1.9% (range from 0% to 6.3%) for monofurcation, 1.0% (range from 0% to 1.4%) for tetrafurcation, 69.9% (range from 58.1% to 92.7%) for bifurcation, and 27% (ranging from 7.3% to 40.4%) for trifurcation. The proportion of MCA anomalies for accessory is 0.03% (range from 0% to 1%), duplication is 0.17% (range from 0% to 3%), and fenestration is 0.15% (range from 0% to 2%). CONCLUSION: The proportions of the branching pattern and anomalies of MCA based on the systematic review are described in this study. This study is the first to systematically review the neuroangiography pattern of MCA and neuroangiography variations/anomalies of MCA in the literature.