Fenestrated basilar artery

Fenestration of the basilar artery (BA) is a segmental duplication of the vessel due to non-fusion of the embryonal arteries and is the second most common vascular disjunction. Reports show 0.3-0.6% incidence on Digital Substracted Angiography (DSA), but since laminar flow is observed in only one lumen, this percentage might be higher in reality; 2% of the patient are diagnosed with fenestrated basilar artery on Magnetic Resonance Angiography (MRA), and 5,63% on autopsy ^{1) 2)}