title: Comparison of 1.5- and 3.0-T MR imaging for evaluating the articular cartilage of the knee joint.
abstract: OBJECTIVE
  To retrospectively compare the diagnostic performance of 1.5- and 3.0-T magnetic resonance (MR) imaging protocols for evaluating the articular cartilage of the knee joint in symptomatic patients.
  
  
  METHODS
  This HIPAA-compliant study was performed with a waiver of informed consent from the institutional review board. The study group consisted of 200 symptomatic patients undergoing MR examination of the knee at 1.5 T (61 men, 39 women; mean age, 38.9 years) or 3.0 T (52 men, 48 women; mean age, 39.1 years), who also underwent subsequent arthroscopic knee surgery. All MR examinations consisted of multiplanar fast spin-echo sequences with similar tissue contrast at 1.5 and 3.0 T. All articular surfaces were graded at arthroscopy by using the Noyes classification system. Three musculoskeletal radiologists retrospectively and independently graded all articular surfaces seen at MR imaging by using a similar classification system. The sensitivity, specificity, and accuracy of the 1.5- and 3.0-T MR protocols for detecting cartilage lesions were determined by using arthroscopy as the reference standard. The z test was used to compare sensitivity, specificity, and accuracy values at 1.5 and 3.0 T.
  
  
  RESULTS
  For all readers combined, the respective sensitivity, specificity, and accuracy of MR imaging for detecting cartilage lesions were 69.3%, 78.0%, and 74.5% at 1.5 T (n = 241) and 70.5%, 85.9%, and 80.1% at 3.0 T (n = 226). The MR imaging protocol had significantly higher specificity and accuracy (P < .05) but not higher sensitivity (P = .73) for detecting cartilage lesions at 3.0 T than at 1.5 T.
  
  
  CONCLUSIONS
  A 3.0-T MR protocol has improved diagnostic performance for evaluating the articular cartilage of the knee joint in symptomatic patients when compared with a 1.5-T protocol.
authors.affiliation: Department of Radiology, University of Wisconsin Hospital, 600 Highland Ave, Clinical Science Center-E3/311, Madison, WI 53792-3252, USA. r.kijowski@hosp.wisc.edu
authors.forename: Richard
authors.initials: R
authors.lastname: Kijowski
authors.forename: Donna G
authors.initials: DG
authors.lastname: Blankenbaker
authors.forename: Kirkland W
authors.initials: KW
authors.lastname: Davis
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Shinki
authors.forename: Lee D
authors.initials: LD
authors.lastname: Kaplan
authors.forename: Arthur A
authors.initials: AA
authors.lastname: De Smet
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007718:Knee Injuries / Q000175:diagnosis*; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult