title: CT and conventional and diffusion-weighted MR imaging in acute stroke: study in 691 patients at presentation to the emergency department.
abstract: OBJECTIVE
  To compare the diagnostic accuracy of computed tomography (CT) and magnetic resonance (MR) imaging in a consecutive series of patients at presentation to the emergency department with symptoms of acute stroke.
  
  
  METHODS
  Clinical data and images obtained in 691 consecutive patients with suspected acute stroke were examined. Results of first and second head CT and brain diffusion-weighted (DW) and conventional MR imaging were compared with each other and with the final neurologic discharge diagnosis.
  
  
  RESULTS
  Five hundred seventy-three patients underwent CT at presentation, with 42% sensitivity (95% CI: 37%, 46%) and 91% specificity (95% CI: 82%, 96%). A total of 173 patients underwent a second CT examination, with 77% sensitivity (95% CI: 70%, 84%) and 79% specificity (95% CI: 49%, 95%). Of 498 MR images, 411 were DW, with 94% sensitivity (95% CI: 1%, 96%) and 97% specificity (95% CI: 88%, 100%), and 87 were conventional, with 70% sensitivity (95% CI: 58%, 81%) and 94% specificity (95% CI: 70%, 100%). By using DW MR imaging in the early period (<6 hours after presentation to emergency department), a 97% sensitivity (95% CI: 92%, 100%) and a 100% specificity (95% CI: 69%, 100%) were achieved, compared with 58% (29%-84%) and 100% (16%-100%), respectively, with conventional MR imaging, and 40% (35%-45%) and 92% (84%-97%), respectively, with CT. Negative predictive value was higher with DW MR imaging (73%) than with conventional (42%) MR imaging or CT (24%). In studies conducted within 12 hours, DW MR imaging achieved substantially superior accuracy than did CT. After 12 hours, accuracy was equivalent.
  
  
  CONCLUSIONS
  In the diagnosis of stroke in the early period (<12 hours after presentation), DW MR imaging is superior to conventional MR imaging and CT.
authors.affiliation: Neuroradiology Division, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, GRB285, Boston, MA 02114, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Mullins
authors.forename: Pamela W
authors.initials: PW
authors.lastname: Schaefer
authors.forename: A Gregory
authors.initials: AG
authors.lastname: Sorensen
authors.forename: Elkan F
authors.initials: EF
authors.lastname: Halpern
authors.forename: Hakan
authors.initials: H
authors.lastname: Ay
authors.forename: Julian
authors.initials: J
authors.lastname: He
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Koroshetz
authors.forename: R Gilberto
authors.initials: RG
authors.lastname: Gonzalez
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002543:Cerebral Hemorrhage / Q000175:diagnosis / Q000000981:diagnostic imaging; D002544:Cerebral Infarction / Q000175:diagnosis / Q000000981:diagnostic imaging; D002648:Child; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D020521:Stroke / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed