title: Improving detection of ischemic lesions at 3 Tesla with optimized diffusion-weighted magnetic resonance imaging.
abstract: OBJECTIVE
  This study compared three different combinations of DWI parameters: three and six diffusion imaging directions (3dir and 6dir, respectively) using b=1000 or 2000 s/mm(2) (b1000 or b2000, respectively) to improve detection of recent ischemic lesions at 3 Tesla (3 T).
  
  
  METHODS
  A total of 47 consecutive patients underwent three DWI scans: 3dir b1000; 6dir b1000; and 6dir b2000. Qualitative visual analysis was performed by three readers based on evaluation of the number of lesions, presence of artifacts and diagnostic confidence. Interobserver agreement, sensitivity, specificity, and positive and negative predictive values were calculated.
  
  
  RESULTS
  Forty-five lesions were detected by 3dir b1000, 52 by 6dir b1000 and 56 by 6dir b2000 in 30 patients. The additional lesions identified by 6dir b2000 were either small or located in the posterior fossa. Sensitivity with 6dir b2000 was significantly higher than with 3dir b1000 (98.1% vs 77.4%; P<0.05).
  
  
  CONCLUSIONS
  At 3 T, 6dir b2000 DWI detected more acute ischemic lesions than 3dir b1000, particularly small lesions and those located in the brain stem.
authors.affiliation: CHU Rennes, Department of Neuroradiology, hôpital Pontchaillou, 2, rue Henri-Le-Guilloux, 35000 Rennes, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Ract
authors.affiliation: CHU Rennes, Department of Neuroradiology, hôpital Pontchaillou, 2, rue Henri-Le-Guilloux, 35000 Rennes, France. Electronic address: jean-christophe.ferre@chu-rennes.fr.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Ferré
authors.affiliation: CHU Rennes, Department of Neurology, hôpital Pontchaillou, 2, rue Henri-Le-Guilloux, 35000 Rennes, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ronzière
authors.affiliation: École des Hautes Études en Santé Publique, Department of Epidemiology, avenue du Professeur-Léon-Bernard, 35043 Rennes, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Leray
authors.affiliation: CHU Rennes, Department of Neuroradiology, hôpital Pontchaillou, 2, rue Henri-Le-Guilloux, 35000 Rennes, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Carsin-Nicol
authors.affiliation: CHU Rennes, Department of Neuroradiology, hôpital Pontchaillou, 2, rue Henri-Le-Guilloux, 35000 Rennes, France.
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Gauvrit
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: DWI; Diffusion; MRI; Stroke