title: MRA study on variation of the circle of willis in healthy Chinese male adults.
abstract: OBJECTIVE
  To investigate the morphology and variation of the circle of Willis (COW) in healthy Chinese male adults.
  
  
  METHODS
  We analyzed cerebral magnetic resonance angiography (MRA) images of 2,246 healthy subjects using typical magnetic resonance imaging (MRI) and MRA. 3D-time of flight (TOF) MRA method was applied to all subjects and the classification was therefore achieved according to the integrity level of COW and the developmental situation of vessels.
  
  
  RESULTS
  The overall incidence of COW integrity was 12.24%, with 7.57% nonvariation integral COW. The incidences of partial integrity and nonintegrity were 70.17% and 17.59%, respectively. The integrity rate of anterior circulation was 78.58%, with a close correlation with A1 segment of the anterior cerebral artery (ACA-A1) developmental condition. The developmental variation rate of ACA-A1 was 28.23% and the variation of the right side was higher than that of the left side. The nonintegrity rate of posterior circulation was 83.93% as the hypoplasia of P1 segment of the posterior cerebral artery (PCA-P1) with an incidence rate of 15.85% for PCA-P1 variation.
  
  
  CONCLUSIONS
  The COW variation is a common phenomenon among the healthy subjects. MRA could enable reflecting the physiological morphology of COW in a comprehensive manner.
authors: Department of Radiology, Civil Aviation General Hospital, Civil Aviation College, Peking University, Beijing 100123, China.
authors: Chuanya
authors: C
authors: Qiu
authors: Department of Radiology, Civil Aviation General Hospital, Civil Aviation College, Peking University, Beijing 100123, China.
authors: Yong
authors: Y
authors: Zhang
authors: Department of Radiology, Civil Aviation General Hospital, Civil Aviation College, Peking University, Beijing 100123, China.
authors: Caixia
authors: C
authors: Xue
authors: Department of Radiology, Civil Aviation General Hospital, Civil Aviation College, Peking University, Beijing 100123, China.
authors: Shanshan
authors: S
authors: Jiang
authors: Department of Radiology, Civil Aviation General Hospital, Civil Aviation College, Peking University, Beijing 100123, China.
authors: Wei
authors: W
authors: Zhang
mesh_terms: D000328:Adult; D020771:Anterior Cerebral Artery; D044466:Asian People; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation; D002941:Circle of Willis / Q000000981:diagnostic imaging* / Q000502:physiology; D006262:Health; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged
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