title: Variations of the posterior cerebral artery diagnosed by MR angiography at 3 tesla.
abstract: BACKGROUND
  Fenestration, early bifurcation, and duplication of the posterior cerebral artery (PCA) and the so-called hyperplastic anterior choroidal artery (AChA), considered a variation of the PCA, are rare. We evaluated the prevalence and characteristic features of these PCA variations on magnetic resonance (MR) angiography.
  
  
  METHODS
  We reviewed intracranial MR angiographic images of 2402 patients examined using a 3-tesla scanner. Images from the skull base to the intracranial region were obtained using the standard time-of-flight technique. We excluded images of 52 patients with insufficient image quality or occlusion of the PCA(s) and retrospectively evaluated the images of 2350 patients using a picture archiving and communication system.
  
  
  RESULTS
  We observed PCA fenestration in eight (0.34%) patients, most at the P1 segment and P1-P2 junction and all small in size, early bifurcation at the P1-P2 junction or proximal P2A segment in eight (0.34%) patients, complete duplication in one patient, and hyperplastic AChA in 13 (0.55%) patients. Eleven of the 13 hyperplastic AChAs supplied only the territory of the temporal branch of the PCA, and the remaining two supplied the entire territory of the PCA.
  
  
  CONCLUSIONS
  We observed PCA variations in 30 (1.28%) patients. We believe the name "hyperplastic AChA" inaccurately describes variations of the PCA in which the AChA supplies part of or all of the territory of the PCA and propose "accessory PCA" to describe an AChA that supplies part of the territory of the PCA or "replaced PCA" to describe that vessel that supplies the territory all branches of the PCA.
authors.affiliation: Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan. auchino@saitama-med.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Uchino
authors.affiliation: Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Saito
authors.affiliation: Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan.
authors.forename: Nanami
authors.initials: N
authors.lastname: Okano
authors.affiliation: Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Tanisaka
mesh_terms: D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020769:Posterior Cerebral Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Anterior choroidal artery; Arterial variation; Magnetic resonance angiography; Posterior cerebral artery; Posterior communicating artery