title: Usefulness of meniscal width to transverse diameter ratio on coronal MRI in the diagnosis of incomplete discoid lateral meniscus.
abstract: OBJECTIVE
  To evaluate the clinical utility of the meniscal width to transverse diameter ratio (L/M ratio) of the lateral meniscus in the diagnosis of incomplete discoid lateral meniscus (IDLM) as compared with the arthroscopic diagnosis, meniscal width to tibial diameter ratio (L/T ratio) and conventional lateral meniscus width criteria.
  
  
  METHODS
  This retrospective study sample included 41 patients with IDLM who underwent knee magnetic resonance imaging (MRI) and arthroscopy, as well as 50 controls with normal lateral menisci. MRI examinations were interpreted independently by two radiologists, both of whom were blinded to clinical information and radiological reports. Assessment of meniscal width (L), maximal transverse diameter of the lateral meniscus (M), and transverse diameter of the tibia (T) was carried out on central coronal sections that were observed to pass through the medial collateral ligament. L/M and L/T ratios were calculated. These results were correlated with arthroscopic findings and analysed statistically using categorical regression analysis and non-parametric correlation analysis. Using arthroscopic findings as the standard of reference, sensitivity and specificity were calculated for: (1) 12, 13, 14, and 15 mm meniscal width thresholds; (2) 40%, 50%, 60%, and 70% L/M ratio thresholds; and (3) 15%, 18%, 20%, and 25% L/T ratio thresholds.
  
  
  RESULTS
  The mean L/M ratio of the IDLM was approximately 67% and was statistically significantly higher than the control (44%). The best diagnostic discrimination was achieved using a threshold of 50%. The mean L/T ratio of the IDLM was approximately 23% and was statistically significant. The best diagnostic discrimination was achieved using a threshold of 18%. The threshold of 13 mm of meniscal width also showed high sensitivity and high specificity.
  
  
  CONCLUSIONS
  The use of the L/M ratio or L/T ratio in combination with meniscal width criteria may be a useful method for evaluating IDLM.
authors.affiliation: Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Republic of Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Park
authors.affiliation: Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Republic of Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Radiology, Myongji Hospital, Koyang, Gyonggido, Republic of Korea. Electronic address: radiology11@hanmail.net.
authors.forename: N-H
authors.initials: NH
authors.lastname: Park
authors.affiliation: Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Republic of Korea.
authors.forename: E C
authors.initials: EC
authors.lastname: Chung
authors.affiliation: Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Republic of Korea.
authors.forename: J Y
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Republic of Korea.
authors.forename: M S
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Radiology, Dongguk University Ilsan Hospital, Koyang, Gyonggido, Republic of Korea.
authors.forename: E J
authors.initials: EJ
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000002:abnormalities / Q000473:pathology*; D008875:Middle Aged; D011237:Predictive Value of Tests; D012015:Reference Standards; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013977:Tibia / Q000002:abnormalities / Q000473:pathology*