title: Magnetic Resonance Imaging in Acute Ischemic Stroke Patients with Mild Symptoms: An Opportunity to Standardize Intravenous Thrombolysis.
abstract: BACKGROUND
  Patients presenting with mild stroke symptoms are excluded inconsistently from intravenous (IV) thrombolysis. We aimed to compare acute magnetic resonance imaging findings in patients with mild symptoms to those with more severe deficits to identify clinically mild patients who might benefit from IV thrombolysis.
  
  
  METHODS
  We retrospectively studied consecutive stroke patients presenting with perfusion deficit who underwent time-of-flight magnetic resonance angiography within 24 hours of time last seen normal. Two raters measured the lesion volumes on diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) with mismatch (MM) calculated as PWI minus DWI. Occlusion site was categorized as "proximal," "distal," or "magnetic resonance angiography-negative" by consensus review. Stroke with mild symptoms was defined as admit National Institutes of Health Stroke Scale score of 4 or less. Values were reported as n (%).
  
  
  RESULTS
  Ninety-one patients were included; 56 (61.5%) with nonmild and 35 (38.5%) with mild symptoms. After stratifying for occlusion site, there were no differences in PWI and MM lesion volumes for the nonmild versus mild patients (P = .34-.98 and P = .54-1, respectively). Furthermore, there was a trend for thrombolyzed mild stroke patients (88%, n = 7 of 8) to more likely have a favorable clinical outcome (discharge modified Rankin score ≤ 2) versus untreated patients (70%, n = 16 of 23).
  
  
  CONCLUSIONS
  When present, conspicuous vessel occlusions in clinically mild stroke patients are concomitant with similar perfusion deficit and MM volumes in more clinically severe stroke patients. Coupled with a trend toward better outcomes in mild stroke patients who were treated with IV tissue plasminogen activator (t-PA), this could indicate that advanced imaging may be used in standardizing the way these patients are selected for IV t-PA therapy.
authors.affiliation: Stroke Diagnostics and Therapeutics Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland.
authors.forename: Tyler A
authors.initials: TA
authors.lastname: Brown
authors.affiliation: Stroke Diagnostics and Therapeutics Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland.
authors.forename: Marie
authors.initials: M
authors.lastname: Luby
authors.affiliation: Stroke Diagnostics and Therapeutics Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland.
authors.forename: Jignesh
authors.initials: J
authors.lastname: Shah
authors.affiliation: Stroke Diagnostics and Therapeutics Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Giannakidis
authors.affiliation: Stroke Diagnostics and Therapeutics Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland. Electronic address: LatourL@ninds.nih.gov.
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Latour
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D020521:Stroke / Q000175:diagnosis / Q000209:etiology*; D015912:Thrombolytic Therapy / Q000379:methods* / Q000592:standards*; D014057:Tomography, X-Ray Computed
keywords: DWI; Mild stroke; PWI; infarction; minor stroke; volumetric MRI