title: Grading anterior cruciate ligament graft injury after ligament reconstruction surgery: diagnostic efficacy of oblique coronal MR imaging of the knee.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the diagnostic efficacy of using additional oblique coronal MRI of the knee for grading anterior cruciate ligament (ACL) graft injury after ligament reconstruction surgery.
  
  
  METHODS
  We retrospectively reviewed 51 consecutive MR knee examinations of 48 patients who underwent both ACL reconstruction and follow-up arthroscopy. The MR examinations included the orthogonal axial, sagittal, coronal images and the oblique coronal T2-weighted images, which were oriented in parallel with the course of the femoral intercondylar roof. Two radiologists independently evaluated the status of the ACL grafts with using the routine knee MRI and then with adding the oblique coronal imaging. The severity of ACL graft injury was graded using a 3-point system from MR images as intact, partial tear or complete tear, and the results were compared with the arthroscopic results. Weighted kappa statistics were used to analyze the diagnostic accuracies of the knee MRI with and without the additional oblique coronal imaging. For each evaluation, the observers reported a confidence level for grading the ACL graft injuries in the two imaging groups.
  
  
  RESULTS
  The weighted kappa values according to the routine knee MRI were 0.555 (reader 1) and 0.515 (reader 2). The inclusion of additional oblique coronal imaging increased the weighted kappa values to 0.666 (reader 1) and 0.611 (reader 2). The mean confidence levels by each reader were significantly higher (p < 0.01, paired t-test) with the additional oblique coronal imaging than by using the routine knee MRI alone.
  
  
  CONCLUSIONS
  The additional use of oblique coronal MRI of the knee improves both the diagnostic accuracy and confidence for grading ACL graft injury.
authors.affiliation: Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sung Gyu
authors.initials: SG
authors.lastname: Moon
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Hong
authors.forename: Ja-Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Woo Sun
authors.initials: WS
authors.lastname: Jun
authors.forename: Jung-Ah
authors.initials: JA
authors.lastname: Choi
authors.forename: Eun-Ah
authors.initials: EA
authors.lastname: Park
authors.forename: Heung Sik
authors.initials: HS
authors.lastname: Kang
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Kwon
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000473:pathology* / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D001182:Arthroscopy; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D007718:Knee Injuries / Q000145:classification*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies