title: Association between anatomical variations of the posterior communicating artery and the presence of aneurysms.
abstract: OBJECTIVE
  Posterior communicating artery aneurysms (PcoAA) account for 30-35% of intracranial aneurysms. The anatomical factors involved in the formation of PCoAA are poorly known. The study aimed to investigate the anatomical variations in the posterior communicating artery (PcoAs) and the presence of PCoAA.
  
  
  METHODS
  All 154 patients hospitalized from January 2008 to December 2013 at the department of neurology of our hospital were included in this study; 76 were confirmed with PCoAA upon cerebral angiography and 78 were confirmed without cranial artery aneurysm (controls). According to the blood supply pattern, variations of the PCoAA were classified as Type P0, P-I, or P-II. The angles of C7 and C6 of the internal carotid artery on each side were analyzed.
  
  
  RESULTS
  Compared with controls, patients with PCoAA had a higher frequency of abnormal posterior communicating artery (Types P-I and P-II) (p < 0.001). The angles of C7 and C6 on the contralateral side in the PCoAA group were significantly greater than on the affected side, and significantly lesser than in controls (p < 0.001). There was no difference in the angle between the culprit artery and the contralateral one.
  
  
  CONCLUSIONS
  Abnormal PCoAs (Types P-I and P-II) might be more vulnerable to PCoAA development, and Type P-II was the most vulnerable. There was a correlation between the angles of C7 and C6 part of the internal carotid artery and the presence of symptomatic PCoAA, with smaller angles being associated with increased frequency of symptomatic PCoAA.
authors.affiliation: b Department of Neurology , The Third People's Hospital of Dalian , Dalian , China.
authors.forename: Teng
authors.initials: T
authors.lastname: Hu
authors.affiliation: a Department of Neurology , Second Hospital of Dalian Medical University , Dalian , China.
authors.forename: Dongdong
authors.initials: D
authors.lastname: Wang
keywords: Aneurysms; Digital subtraction angiography; Hemodynamics; Internal carotid artery; Posterior communicating artery aneurysm