Middle cerebral artery duplication : classification and clinical implications

Area of Science:

• Neuroanatomy
• Vascular Neurology
• Embryology

Background:

• The embryological origin of duplicated middle cerebral arteries (DMCAs) remains unclear despite various proposed explanations.
• Understanding DMCA origins is crucial for interpreting neuroimaging findings and potential clinical implications.

Purpose of the Study:

• To review anomalous duplicated middle cerebral arteries (DMCAs) and propose a theory for their diverse origins, sizes, and courses.
• To differentiate between types of DMCAs based on their anatomical characteristics.

Main Methods:

• Retrospective review of 1,250 cerebral angiographies, 1,452 CT-angiographies, and 2,527 MR-angiographies.
• Identification and classification of duplicated middle cerebral arteries (DMCAs) based on origin and morphology.

Main Results:

• Twenty-five cases of duplicated middle cerebral arteries (DMCAs) were identified.
• Type A DMCAs (n=8) originated near the internal carotid artery terminal, with similar diameters and parallel courses to the other MCA branch.
• Type B DMCAs (n=17) originated between the anterior choroidal artery and internal carotid artery terminus, showing varied diameters and courses (parallel or temporal lobe-curving).

Conclusions:

• Type A DMCAs are likely early bifurcations of the middle cerebral artery (MCA).
• Type B DMCAs are proposed to be direct bifurcations of the MCA trunk or early ramifications of the MCA's temporal branch.