title: Assessment of collateral flow with multi-phasic CT: correlation with diffusion weighted MRI in MCA occlusion.
abstract: OBJECTIVE
  To correlate collateral flow on multiphasic contrast enhancement computed tomography (CT) and graded ischemic changes on diffusion weighted MR in patients with acute middle cerebral artery (MCA) infarction.
  
  
  METHODS
  A retrospective evaluation of diffusion weighted images (DWIs) and three phasic contrast enhanced CT (CECT) was performed on 11 patients with MCA occlusions. The area of ischemic change on DWIs was graded according to the Alberta Stroke Program Early CT Score (ASPECTS) criteria. To evaluate collateral flow on three phasic CECT, we counted the number of contrast enhancing MCA branches distal to the occlusion site at the sylvian fissure from predetermined axial images. The collateral ratios of counted numbers to those at the normal side were calculated at each phase (CR1, CR2, CR3). We then compared collateral ratios from the three phasic CECT with ASPECTS data from DWIs.
  
  
  RESULTS
  Collateral ratios from the three phasic CECT were determined to be CR1 .48 ± .27, CR2 .73 ± .36 and CR3 .72 ± .30. We discovered a correlation between both the CR2 and ASPECTS (r= .675, P= .023) and the CR3 and ASPECTS (r= .664, P= .026).
  
  
  CONCLUSIONS
  The number of contrast enhancing branches distal to the MCA occlusion, as counted in the sylvian fissure on later phase images of multiphasic CECT, reflects the status of collateral flow, and correlates with ASPECTS on DWIs.
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: So-Lyung
authors.initials: SL
authors.lastname: Jung
authors.forename: Youn-Joo
authors.initials: YJ
authors.lastname: Lee
authors.forename: Kook-Jin
authors.initials: KJ
authors.lastname: Ahn
authors.forename: Young-In
authors.initials: YI
authors.lastname: Kim
authors.forename: Kwang-Soo
authors.initials: KS
authors.lastname: Lee
authors.forename: Yong-Sam
authors.initials: YS
authors.lastname: Shin
authors.forename: Kwan-Sung
authors.initials: KS
authors.lastname: Lee
authors.forename: Bum-Soo
authors.initials: BS
authors.lastname: Kim
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies; D020521:Stroke / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed