title: Clinically Confirmed Stroke With Negative Diffusion-Weighted Imaging Magnetic Resonance Imaging: Longitudinal Study of Clinical Outcomes, Stroke Recurrence, and Systematic Review.
abstract: OBJECTIVE
  We sought to establish whether the presence (versus absence) of a lesion on magnetic resonance imaging (MRI) with diffusion weighting (DWI-MRI) at presentation with acute stroke is associated with worse clinical outcomes at 1 year.
  
  
  METHODS
  We recruited consecutive patients with a nondisabling ischemic stroke and performed DWI-MRI. Patients were followed up at 1 year to establish stroke recurrence (clinical or on MRI), cognitive impairment (Addenbrooke Cognitive Assessment Revised,<88) and modified Rankin Scale.
  
  
  RESULTS
  A median of 4 days post stroke, one third (76/264; 29%) of patients did not have a DWI lesion (95% confidence interval, 23%-35%). There was no statistically significant difference between those with and without a DWI lesion with respect to age or vascular risk factors. Patients without a lesion were more likely to be women or have previous stroke. At 1 year, 11 of 76 (14%) patients with a DWI-negative index stroke had a clinical diagnosis of recurrent stroke or transient ischemic attack, 33% had cognitive impairment (Addenbrooke Cognitive Assessment Revised<88), and 40% still had modified Rankin Scale>1, no different from DWI-positive patients; DWI-positive patients were more likely to have a new lesion on MRI (14%), symptomatic or asymptomatic, than DWI-negative patients (2%; P=0.02). Our data were consistent with 6 other studies (total n=976), pooled proportion of DWI-negative patients was 21% (95% confidence interval, 12%-32%).
  
  
  CONCLUSIONS
  Nearly one third of patients with nondisabling stroke do not have a relevant lesion on acute DWI-MRI. Patients with negative DWI-MRI had no better prognosis than patients with a lesion. DWI-negative stroke patients should receive secondary prevention.
authors.affiliation: From the Centre for Clinical Brain Sciences, Western General Hospital, Edinburgh, United Kingdom.
authors.forename: Stephen D J
authors.initials: SD
authors.lastname: Makin
authors.affiliation: From the Centre for Clinical Brain Sciences, Western General Hospital, Edinburgh, United Kingdom.
authors.forename: Fergus N
authors.initials: FN
authors.lastname: Doubal
authors.affiliation: From the Centre for Clinical Brain Sciences, Western General Hospital, Edinburgh, United Kingdom.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Dennis
authors.affiliation: From the Centre for Clinical Brain Sciences, Western General Hospital, Edinburgh, United Kingdom. Joanna.wardlaw@ed.ac.uk.
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Wardlaw
mesh_terms: D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis* / Q000453:epidemiology / Q000378:metabolism*; D016896:Treatment Outcome
keywords: cognition; diffusion; ischemic attack, transient; magnetic resonance imaging; stroke