title: Diffusion lesion reversal after thrombolysis: a MR correlate of early neurological improvement.
abstract: OBJECTIVE
  In acute stroke, diffusion-weighted imaging (DWI) lesions are commonly considered markers of irreversible ischemia yet can occasionally reverse. However, the extent and clinical correlates of DWI reversal in thrombolyzed patients remain unclear. We assessed the extent of reversible acute DWI lesions (RADs) and their relationships with clinical outcome in patients thrombolyzed≤4.5 hours from onset.
  
  
  METHODS
  Data were retrospectively analyzed. RAD was defined as an acute DWI lesion not part of a 24-hour DWI lesion as determined voxelwise. Associations with an early neurological improvement (early neurological improvement=ΔNational Institutes of Health Stroke Scale≥8 or National Institutes of Health Stroke Scale≤2 at 24 hours) or an excellent outcome (modified Rankin Scale≤1) were assessed in multivariate analyses.
  
  
  RESULTS
  One hundred seventy-six patients were included. The median (interquartile range) time to treatment from onset was 150 minutes (120-194). Eighty-nine patients (50%) exhibited visually-detectable RAD irrespective of its extent. Over the whole population, the median percentage and volume of RAD were 11% (4-36) and 2.4 mL (0.5-8). Subtracting RAD from initial DWI altered perfusion-weighted imaging-DWI classification in 5 of 100 patients (shift from "no mismatch" to "mismatch" profile in all). Percent RAD was significantly greater in patients treated≤3 hours (P=0.049), without proximal occlusion (P=0.003), and in 24-hour recanalizers (P<0.001). Early neurological improvement was independently associated with percent RAD. This association increased with percent RAD split in quartiles in a "dose-dependent" manner (P for trend=0.01). Excellent outcome was independently associated with percent RAD (P for trend<0.001).
  
  
  CONCLUSIONS
  DWI reversal was often sizeable in patients treated≤4.5 hours. It was strongly associated with, albeit not necessarily causal for, early neurological improvement.
authors.affiliation: Department of Radiology, Université Paris Descartes Sorbonne Paris Cité, Centre de Psychiatrie et Neursciences, Centre Hospitalier Sainte-Anne, 1 rue Cabanis, 75674 Paris Cedex 14, France.
authors.forename: Marc-Antoine
authors.initials: MA
authors.lastname: Labeyrie
authors.forename: Guillaume
authors.initials: G
authors.lastname: Turc
authors.forename: Agathe
authors.initials: A
authors.lastname: Hess
authors.forename: Patrice
authors.initials: P
authors.lastname: Hervo
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Mas
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Meder
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Baron
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Touzé
authors.forename: Catherine
authors.initials: C
authors.lastname: Oppenheim
mesh_terms: D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function; D012189:Retrospective Studies; D020521:Stroke / Q000188:drug therapy* / Q000473:pathology*; D015912:Thrombolytic Therapy; D016896:Treatment Outcome