title: Noncontrast Computed Tomography versus Computed Tomography Angiography Source Images for Predicting Final Infarct Size in Anterior Circulation Acute Ischemic Stroke: a Prospective Cohort Study.
abstract: BACKGROUND
  There has been a recent debate regarding the superiority of computed tomography angiography source images (CTASIs) over noncontrast computed tomography (NCCT) to predict the final infarct size in acute ischemic stroke (AIS). We hypothesized that the parenchymal abnormality on CTASI in faster scanners would overestimate ischemic core.
  
  
  METHODS
  This prospective study assessed the correlation of Alberta Stroke Program Early CT Score (ASPECTS) on NCCT, CTASI, and computed tomography perfusion (CTP) with final infarct size in patients within 8 hours of AIS. Follow-up with NCCT or diffusion-weighted magnetic resonance imaging (MRI) was performed at 24 hours. Correlations of NCCT and CTASI with final infarct size and with CTP parameters were assessed. Subgroup analysis was performed in patients who underwent intravenous thrombolysis or mechanical thrombectomy. Inter-rater reliability was tested using Spearman's rank correlation. A P value less than .05 was considered statistically significant.
  
  
  RESULTS
  A total of 105 patients were included in the final analysis. NCCT had a stronger correlation with the final infarct size than did CTASI (Spearman's ρ = .85 versus .78, P = .13). We found an overestimation of the final infarct size by CTASI in 47.6% of the cases, whereas NCCT underestimated infarct size in 60% of the patients. NCCT correlated most strongly with CBV (ρ = .93), whereas CTASI correlated most strongly with CBF (ρ = .87). Subgroup analysis showed less correlation of CTASI with final infarct size in the group that received thrombolysis versus the group that did not (ρ = .70 versus .88, P = .01).
  
  
  CONCLUSIONS
  In a 256-slice scanner, the CTASI parenchymal abnormality includes ischemic penumbra and thus overestimates final infarct size-this could result in inappropriate exclusion of patients from thrombolysis or thrombectomy.
authors: Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India. Electronic address: mecooldoc@yahoo.co.in.
authors: Amritendu
authors: A
authors: Mukherjee
authors: Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Prakash
authors: P
authors: Muthusami
authors: Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India.
authors: Aneesh
authors: A
authors: Mohimen
authors: Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India.
authors: Srinivasan
authors: S
authors: K
authors: Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India.
authors: Babunath
authors: B
authors: B
authors: Comprehensive Stroke Care Program, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India.
authors: Sylaja
authors: S
authors: Pn
authors: Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India.
authors: Chandrasekharan
authors: C
authors: Kesavadas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta; D001921:Brain / Q000000981:diagnostic imaging*; D020520:Brain Infarction / Q000000981:diagnostic imaging* / Q000628:therapy; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000628:therapy; D002533:Cerebral Angiography / Q000295:instrumentation / Q000379:methods; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D020521:Stroke / Q000000981:diagnostic imaging* / Q000628:therapy; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: 256-Slice computed tomography; ASPECTS; CT angiography source image; final infarct size; noncontrast CT