title: Multiphase CT angiography increases detection of anterior circulation intracranial occlusion.
abstract: OBJECTIVE
  To evaluate whether the use of multiphase CT angiography (CTA) improves interrater agreement for intracranial occlusion detection between stroke neurology trainees and an expert neuroradiologist.
  
  
  METHODS
  A neuroradiologist and 2 stroke neurology fellows independently reviewed 100 prospectively collected single-phase and multiphase CTA scans from acute ischemic stroke patients with mild symptoms (NIH Stroke Scale score ≤5). The presence and location of a vascular occlusion(s) were documented. Interrater agreement single- and multiphase CTA was quantified using unweighted κ statistics. We assessed for any occlusions, anterior vs posterior occlusions, and pial vessel asymmetry.
  
  
  RESULTS
  Using multiphase CTA, the neuroradiologist detected 50 scans with anterior circulation occlusions and 15 scans with posterior circulation occlusions. Median reading time was 2 minutes per scan. Median reading time for the neurologists was 3 minutes per multiphase CTA scan. Interrater agreement was fair between the 2 neurologists and neuroradiologist when using single-phase CTA (κ = 0.45 and 0.32). Agreement improved minimally when stratified by anterior vs posterior circulation. When using multiphase CTA, agreement was high for detection of occlusion or asymmetry of pial vessels in the anterior circulation (κ = 0.80 and 0.84).
  
  
  CONCLUSIONS
  Multiphase CTA improves diagnostic accuracy in minor ischemic stroke for detection of anterior circulation intracranial occlusion.
  
  
  METHODS
  This study provides Class II evidence that multiphase CTA, compared to single-phase CTA, improves the interrater agreement between stroke neurology trainees and an expert neuroradiologist for detecting anterior circulation intracranial vascular occlusion in patients with minor acute ischemic strokes.
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Amy Y X
authors.initials: AY
authors.lastname: Yu
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Zerna
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Zarina
authors.initials: Z
authors.lastname: Assis
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Jessalyn K
authors.initials: JK
authors.lastname: Holodinsky
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Privia A
authors.initials: PA
authors.lastname: Randhawa
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Najm
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Mayank
authors.initials: M
authors.lastname: Goyal
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Bijoy K
authors.initials: BK
authors.lastname: Menon
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Demchuk
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada.
authors.forename: Shelagh B
authors.initials: SB
authors.lastname: Coutts
authors.affiliation: From the Department of Clinical Neurosciences (A.Y.X.Y., C.Z., P.A.R., M.N., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), Community Health Sciences (A.Y.X.Y., J.K.H., B.K.M., S.B.C., M.D.H.), Department of Radiology (Z.A., M.G., B.K.M., A.M.D., S.B.C., M.D.H.), and Hotchkiss Brain Institute (M.G., B.K.M., A.M.D., S.B.C., M.D.H.), University of Calgary, Canada. michael.hill@ucalgary.ca.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hill
mesh_terms: D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging; D002533:Cerebral Angiography / Q000379:methods*; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging*; D000072226:Computed Tomography Angiography / Q000379:methods*; D006801:Humans; D015588:Observer Variation