title: Detour sign in the diagnosis of subluxation of the long head of the biceps tendon with arthroscopic correlation.
abstract: OBJECTIVE
  To determine whether detection of the detour sign via MRI indicates subluxation of the long head of the biceps tendon (SLBT) in the shoulder joint and to investigate the association of SLBT with the degeneration of the long head of the biceps tendon (LBT) and rotator cuff tears.
  
  
  METHODS
  This retrospective study included 65 patients with shoulder pain who underwent shoulder MRI and arthroscopic surgery. When axial images revealed that the LBT was displaced over the inner rim of the bicipital groove with some remaining contact with the groove (Criterion 1), or demonstrated a "detour sign" of the biceps tendon (Criterion 2), the lesion was diagnosed as an SLBT. Shoulder arthroscopy was used as the reference standard.
  
  
  RESULTS
  Arthroscopy identified SLBT in 18 patients. When the MRI diagnosis was based on Criterion 1 alone, SLBT was diagnosed with a sensitivity of 44.4-55.6% and 75.4-80% accuracy. However, when the MRI diagnosis was based on Criteria 1 plus 2, SLBT was diagnosed with a sensitivity of 83.3-94.4% and 78.5-81.5% accuracy. There was a significant difference (p < 0.05) in the diagnostic sensitivity of Criteria 1 and 2.
  
  
  CONCLUSIONS
  The detour sign based on axial MRI may be regarded an additional useful anatomical feature that improves the diagnostic performance of MRI in the identification of SLBT lesions. Advances in knowledge: Recognition of the detour sign may enhance the diagnostic performance of the conventional MRI protocol over the MR arthrography protocol for SLBT.
authors.affiliation: 1 Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon, Republic of Korea.
authors.forename: Eun K
authors.initials: EK
authors.lastname: Khil
authors.affiliation: 1 Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon, Republic of Korea.
authors.forename: Jang G
authors.initials: JG
authors.lastname: Cha
authors.affiliation: 2 Department of Radiology, Research Institute of Radiological Science, Medical Convergence Research Institute and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Ji S
authors.initials: JS
authors.lastname: Yi
authors.affiliation: 3 Department of Radiology, Soonchunhyang University Seoul Hospital, Seoul, Republic of Korea.
authors.forename: Hyun-Joo
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: 4 Department of Orthopedics, Soonchunhyang University Bucheon Hospital, Bucheon, Republic of Korea.
authors.forename: Kyung D
authors.initials: KD
authors.lastname: Min
authors.affiliation: 5 Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Young C
authors.initials: YC
authors.lastname: Yoon
authors.affiliation: 6 Department of Internal Medicine, Division of Rheumatology, Soonchunhyang University Bucheon Hospital, Bucheon, Republic of Korea.
authors.forename: Chan H
authors.initials: CH
authors.lastname: Jeon
mesh_terms: D000368:Aged; D001182:Arthroscopy / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D000070636:Rotator Cuff Injuries / Q000175:diagnosis / Q000601:surgery; D012421:Rupture; D020069:Shoulder Pain / Q000175:diagnosis* / Q000209:etiology; D013708:Tendon Injuries / Q000175:diagnosis* / Q000601:surgery