Multidetector CT angiography of the Circle of Willis: association of its variants with carotid artery disease and brain ischemia.

• CoW variant distribution significantly differed in the study and control groups (p<0.001). • ICA stenosis was the only independent predictor of CoW morphology (p<0.001). • Severely compromised CoW configuration showed significant association with brain ischemia (p=0.002).