title: Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee.
abstract: OBJECTIVE
  This study assesses the accuracy of 3-Tesla (3-T) conventional MR imaging, 3-T MR arthrography, and the combined use of conventional MR and MR arthrography in the diagnosis of meniscal retears as compared with arthroscopy. The study also assess whether there are false-negative cases in which injected contrast does not extend into the meniscus despite a meniscal retear being seen on arthroscopy.
  
  
  METHODS
  One hundred consecutive knee MR arthrograms performed on patients with previous knee surgery were reviewed retrospectively. 3-T conventional MR imaging, 3-T MR arthrography, and the combined use of conventional MR and MR arthrography were assessed for meniscal retears as compared with arthroscopy. The criterion used to diagnose a meniscal retear on MR arthrogram was injected contrast tracking into the meniscus. All patients underwent second-look arthroscopy.
  
  
  RESULTS
  Seventy-four patients had conventional MR findings consistent with a meniscal retear. In 83 of the 100 patients, intraarticular contrast helped in demonstrating a retear. In ten patients, there were MR findings consistent with a meniscal retear despite intra-articular contrast not tracking into the meniscus. Ninety-four of the 100 patients had meniscal retears on second-look arthroscopy. Three-Tesla conventional MR examination was 78 % sensitive and 75 % specific, MR arthrogram examination was 88 % sensitive and 100 % specific, and the combined use of MR and MR arthrogram imaging was 98 % sensitive and 75 % specific in the diagnosis of a meniscal retear.
  
  
  CONCLUSIONS
  The combined use of 3-T MR and MR arthrography allows for high sensitivity and specificity in meniscal retear detection. In some patients, intraarticular contrast will not track into a meniscal retear. When MR findings are consistent with a meniscal retear but contrast does not extend into the meniscus, a meniscal retear is likely.
authors.affiliation: NSI, 255 North Sykes Creek Parkway, Merritt Island, FL, 33573, USA, tmageerad@cfl.rr.com.
authors.forename: Thomas
authors.initials: T
authors.lastname: Magee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001175:Arthrography / Q000379:methods*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007270:Injections, Intra-Articular; D007718:Knee Injuries / Q000175:diagnosis*; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology*; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis*; D012008:Recurrence; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D000070600:Tibial Meniscus Injuries; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
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