title: Final infarct volume estimation on 1-week follow-up MR imaging is feasible and is dependent on recanalization status.
abstract: OBJECTIVE
  We aim to characterize infarct volume evolution within the first month post-ischemic stroke and to determine the effect of recanalization status on early infarct volume estimation.
  
  
  METHODS
  Ischemic stroke patients recruited for the MONITOR and VISION studies were retrospectively screened and patients who had infarcts on diffusion-weighted imaging (DWI) at baseline and had at least two follow-up MR scans (n = 56) were included. Pre-defined target imaging time points, obtained on a 3-T MR scanner, were 12 hours (h), 24 h, 7 days, and ≥30 days post-stroke. Infarct tissue was manually traced blinded to the images at the other time points. Infarct expansion index was calculated by dividing infarct volume at each follow-up time point by the baseline DWI infarct volume. Recanalization was assessed within 24 h post-stroke. Correlation and statistical comparison analysis were done using the Spearman, Mann-Whitney, and Kruskal-Wallis tests.
  
  
  RESULTS
  Follow-up infarct volumes were positively correlated with the baseline infarct volume (ρ > 0.81; p < 0.001) where the strongest correlation existed between baseline and 7-day post-stroke infarct volumes (ρ = 0.92; p < 0.001). The strongest correlation among the follow-up imaging was found between infarct volumes 7-day post-stroke and ≥30-day time points (ρ = 0.93; p < 0.001). Linear regression showed a close-to unity slope between 7-day and final infarct volumes (slope = 1.043; p < 0.001). Infarct expansion was higher in the non-recanalized group than the recanalized group at the 7-day (p = 0.001) and ≥30-day (p = 0.038) time points.
  
  
  CONCLUSIONS
  Final infarct volume can be approximated as early as 7 days post-stroke. Final infarct volume approximation is significantly associated with recanalization status.
authors.affiliation: Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada ; Seaman Family Centre, Foothills Medical Centre, Alberta Health Services, Calgary, Alberta, Canada ; Biomedical Engineering, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Krongold
authors.affiliation: Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada ; Seaman Family Centre, Foothills Medical Centre, Alberta Health Services, Calgary, Alberta, Canada ; King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Almekhlafi
authors.affiliation: Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada ; Seaman Family Centre, Foothills Medical Centre, Alberta Health Services, Calgary, Alberta, Canada ; Calgary Stroke Program, Foothills Medical Centre, Calgary, Alberta, Canada.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Demchuk
authors.affiliation: Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada ; Seaman Family Centre, Foothills Medical Centre, Alberta Health Services, Calgary, Alberta, Canada ; Calgary Stroke Program, Foothills Medical Centre, Calgary, Alberta, Canada.
authors.forename: Shelagh B
authors.initials: SB
authors.lastname: Coutts
authors.affiliation: Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada ; Seaman Family Centre, Foothills Medical Centre, Alberta Health Services, Calgary, Alberta, Canada ; Biomedical Engineering, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Frayne
authors.affiliation: Radiology and Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada ; Seaman Family Centre, Foothills Medical Centre, Alberta Health Services, Calgary, Alberta, Canada ; Biomedical Engineering, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Armin
authors.initials: A
authors.lastname: Eilaghi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000503:physiopathology* / Q000628:therapy; D038524:Diffusion Magnetic Resonance Imaging; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020521:Stroke / Q000503:physiopathology* / Q000628:therapy; D013318:Stroke Volume / Q000502:physiology*; D016896:Treatment Outcome
keywords: Infarct volume; Ischemic stroke; MRI; Recanalization; Sub-acute