title: Combining magnetic resonance imaging within six-hours of symptom onset with clinical follow-up at 24 h improves prediction of 'malignant' middle cerebral artery infarction.
abstract: BACKGROUND
  A large diffusion-weighted imaging lesion ≤six-hours of symptom onset was found to predict the development of 'malignant' middle cerebral artery infarction with high specificity, positive predictive value, and negative predictive value, but sensitivity was low.
  
  
  OBJECTIVE
  We tested the hypothesis that sensitivity can be improved by adding information from clinical follow-up examination after 24 h.
  
  
  METHODS
  We analyzed data from a prospective, multicenter, observational cohort study of patients with acute ischemic stroke and middle cerebral artery occlusion studied by stroke magnetic resonance imaging ≤six-hours of symptom onset. We used the National Institutes of Health Stroke Scale to assess severity of symptoms after 24 h. We used the Classification and Regression Trees analysis to define the optimal thresholds of diffusion-weighted imaging lesion volume and the National Institutes of Health Stroke Scale after 24 h in patients developing 'malignant' middle cerebral artery infarction. We calculated sensitivity, specificity, positive predictive value, and negative predictive value for two simple predictive models based on acute diffusion-weighted imaging lesion volume alone and acute diffusion-weighted imaging lesion volume together with the National Institutes of Health Stroke Scale after 24 h.
  
  
  RESULTS
  Of 135 patients, 27 (20%) developed a 'malignant' middle cerebral artery infarction. The Classification and Regression Trees analysis identified acute diffusion-weighted imaging lesion ≥78 ml and the National Institutes of Health Stroke Scale score after 24 h ≥22 as optimal cut-offs. Inclusion of the National Institutes of Health Stroke Scale score after 24 h in a simple two-step decision tree increased sensitivity from 0·59 to 0·79, while specificity, positive predictive value, and negative predictive value remained largely unchanged.
  
  
  CONCLUSIONS
  Clinical follow-up examination after 24 h helps identify patients at risk of 'malignant' middle cerebral artery infarction that are missed by predictive algorithms based on early diffusion-weighted imaging lesion volume alone.
authors.affiliation: Department of Neurology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Kruetzelmann
authors.forename: Frank
authors.initials: F
authors.lastname: Hartmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Beck
authors.forename: Eric
authors.initials: E
authors.lastname: Juettler
authors.forename: Oliver C
authors.initials: OC
authors.lastname: Singer
authors.forename: Martin
authors.initials: M
authors.lastname: Köhrmann
authors.forename: Jan F
authors.initials: JF
authors.lastname: Kersten
authors.forename: Jan
authors.initials: J
authors.lastname: Sobesky
authors.forename: Christian
authors.initials: C
authors.lastname: Gerloff
authors.forename: Arno
authors.initials: A
authors.lastname: Villringer
authors.forename: Jens
authors.initials: J
authors.lastname: Fiehler
authors.forename: Tobias
authors.initials: T
authors.lastname: Neumann-Haefelin
authors.forename: Peter D
authors.initials: PD
authors.lastname: Schellinger
authors.forename: Joachim
authors.initials: J
authors.lastname: Röther
authors.forename: Götz
authors.initials: G
authors.lastname: Thomalla
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003663:Decision Trees; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019370:Observation; D011237:Predictive Value of Tests; D012044:Regression Analysis; D012720:Severity of Illness Index; D013997:Time Factors
keywords: acute stroke; diffusion-weighted; magnetic resonance imaging; malignant middle cerebral artery infarction