Evaluation of anatomic variations of Willis circle by 3.0T 3D-TOF MR angiography

Objective To investigate the value of 3.0T three dimensional time-of-flight(3D TOF) magnetic resonance(MR) angiography of anatomic variations of the Willis circle.MethodsSixty-three cases of MR angiograms of the Willis circle,which had anatomic variations but no remarkable abnormalities in the brain and vesseles,were retrospectively analyzed.Results On the MR angiograms,the rate of variation of anterior cerebral artery(ACA) was 74.60%,compound variation of posterior communicating artery(PCoA) and posterior cerebral artery(PCA) was 26.98%,the presence rate of anterior communicating artery(ACoA)was 53.97%,and the presence rate of posterior communicating artery(PCoA) was 58.73%.Conclusion 3.0T 3D-TOF MR angiography is a effective non-invasive method for evaluating anatomic variations of the Willis circle.