Correlation Of Collateral Establishment Of Circle Of Willis And Acute Ischemic Cerebrovascular Disease

Objective To investigate correlation of collateral establishment of circle ofWillis and acute ischemic cerebrovascular diseas（eICVD）by CT angiography (CTA).Methods This retrospective study enrolled231patients with acute ischemiccerebrovascular disease. They were treated in Beijing friendship hospital fromDecember2011to February2013. According to the diagnosis, all patients weredivided in3group: TIA(59cases), posterior circulation ischemia(66cases) andcerebral infarction(106cases), and underwent head CTA and CTP examination. Incerebral infarction group, the patients were divided into anterior circulationinfarction(57cases) and posterior circulation infarction(49cases).The aim of theresearch is to reveal the relation between the cerebral collateral circulation of Williscircle and cerebral ischemic disease. According to its integrity, Willis’ circle wasdivided into four types:（1） Type I, showing an intact circle.(2) Type II, having anincomplete anterior circulation but a complete posterior circulation.(3) Type III,having a complete anterior circulation but an incomplete posterior circulation.(4)Type IV, having an incomplete anterior and posterior circulation. We analyzed therelationship between different types of circle of Willis and acute ICVD. The datawere analyzed by the Analysis of Variance. Presence percentage comparison betweendifferent groups were made by using the χ2test。Result In all231cases with acute ICVD,59patients with TIA,66patients withposterior circulation ischemia and106patients with cerebral infarction. Their headand neck CTA were observed to analyze the collateral circulation of Willis circle,Type I、II、III and IV was found in18（7.8%）、10（4.3%）、89（38.5%）and114 （49.4%）respectively. The frequency of Type I and III in TIA group and posteriorcirculation ischemia group were more than these in cerebral infarction group, whichwere occupied11.9%,7.6%,2.85%,2.85%and49.2%,47.0%,16.0%,1.3%respectively.The frequency of the ACoA segment in each group was found in48(38.4%),42(33.6%),35（33%）,19（18%）respectively, P=0.001. The less cases with infarctionrate and decreased perfusion area were found in patients with completed Willis circle（P=0.000,P=0.002）.Conclusion Our study suggests that the potential of the primary collateralcirculation is ultimately determined by the anatomic variability of Willis circle.Perfusion abnormality in patients with ICVD were associated with the type ofcollateral circulation of Willis circle, especially in collateral anterior circulation.Based on the CT angiography and CT perfusion images, we can get moreinformation about collateral circulation of ICVD patient, which may provide morebenefit for individualized treatment in patients with ICVD.