title: Early and late recurrence of ischemic lesion on MRI: evidence for a prolonged stroke-prone state?
abstract: BACKGROUND
  Based on previous observations of a high rate of ischemic lesion recurrence on diffusion-weighted imaging (DWI) within 1 week after an acute ischemic stroke, the authors hypothesized that silent new ischemic lesions are common between 1 week and 90 days after index stroke and that early lesion recurrence may be associated with late lesion recurrence.
  
  
  METHODS
  The authors studied 80 acute ischemic stroke patients who had initial MRI performed within 48 hours, and follow-up scans at 5 days and at 30 or 90 days after onset. Early lesion recurrences were defined as new ischemic lesions on 5-day DWI, and late lesion recurrences were defined as those on 30- or 90-day DWI or fluid attenuation inversion recovery image. Early lesion recurrence occurring outside the initial perfusion deficit was termed distant lesion recurrence.
  
  
  RESULTS
  Late lesion recurrence occurred in 26%, more frequently observed on 30-day MRI than 90-day MRI (p = 0.016). Early lesion recurrence (OR 4.0; 95% CI 1.3 to 11.7) and distant early lesion recurrence (OR 6.9; 95% CI 1.5 to 32.2) were independently associated with late lesion recurrence by multiple logistic regression analyses.
  
  
  CONCLUSIONS
  There may be a continued risk for recurrent ischemic lesions in the weeks following the clinically symptomatic stroke. Future studies are needed to investigate whether MRI-defined ischemic lesion recurrences predict subsequent clinical recurrence and thus may be a potential surrogate endpoint in stroke secondary prevention trials.
authors.affiliation: Stroke Branch, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1063, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Kang
authors.forename: L L
authors.initials: LL
authors.lastname: Latour
authors.forename: J A
authors.initials: JA
authors.lastname: Chalela
authors.forename: J A
authors.initials: JA
authors.lastname: Dambrosia
authors.forename: S
authors.initials: S
authors.lastname: Warach
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000453:epidemiology*; D015331:Cohort Studies; D003289:Convalescence; D038524:Diffusion Magnetic Resonance Imaging; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D016037:Single-Blind Method; D013997:Time Factors