title: Diagnostic performance of volume and limited oblique MRI of the anterior cruciate ligament compared to knee arthroscopy.
abstract: BACKGROUND
  Many strategies have been used to improve the visualisation of the ACL including sagittal, coronal oblique sequences, and 3D volume imaging. Nevertheless, the ACL may not always be visualised.
  
  
  METHODS
  Two hundred and thirty-one consecutive patients (77 females; 154 males; average age 43.5, range 18 to 82 years; 205 with chronic, 20 acute, and 6 acute on chronic symptoms) underwent knee arthroscopy for mechanical symptoms within a week of MRI. After routine orthogonal sequences, if general MRI radiographers, with over four years experience, were not able to identify the presence of the ACL, then two 3D volume sequences and 2D limited sagittal oblique T1 sequences were performed. Patients requiring extra sequences, missed by the radiography technicians, were recalled. The MRI sequences were evaluated in a blinded fashion by three radiologists, and compared to the knee arthroscopy findings, with the normal ACL acting as internal controls. The radiography technicians performed additional ACL sequences in 63 patients (27%); of these, 10 patients had a partial and 12 patients had a complete ACL tear. Only 2 patients (0.6%) were recalled (one with a normal, and one with a full thickness ACL tear).
  
  
  RESULTS
  The filmed ACL evaluation for complete tears and a normal ACL had a sensitivity of 100%, specificity of 97.1% and accuracy of 97.3%, slightly higher than evaluating on the monitor. Volume sequences had specificities and accuracies over 95%, with good intraobserver reliability (Kappa 0.859, 95% CI 0.705-1.0). Experienced radiographers identified most cases requiring supplementary MRI ACL sequences. An additional volume sequence was beneficial when filmed. Use of the monitor can offer some benefits. Limited oblique T1 sequence of the intercondylar notch was unreliable.
authors.affiliation: Department of Radiological Sciences, University Hospital of North Staffordshire NHS Trust, Stoke on Trent, UK.
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Richards
authors.affiliation: Department of Radiological Sciences, University Hospital of North Staffordshire NHS Trust, Stoke on Trent, UK.
authors.forename: Iain
authors.initials: I
authors.lastname: McCall
authors.affiliation: Department of Radiological Sciences, University Hospital of North Staffordshire NHS Trust, Stoke on Trent, UK.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kraus
authors.affiliation: School of Computing and Mathematics, University of Keele, UK.
authors.forename: Mary
authors.initials: M
authors.lastname: Jones
authors.affiliation: Orthopaedic Surgical Trials Unit, Department of Trauma and Orthopaedic Surgery, Keele University School of Medicine, Guy Hilton Research Centre, Thornburrow Drive, Hartshill, Stoke on Trent, UK.
authors.forename: Gayle
authors.initials: G
authors.lastname: Maffulli
authors.affiliation: Orthopaedic Surgical Trials Unit, Department of Trauma and Orthopaedic Surgery, Keele University School of Medicine, Guy Hilton Research Centre, Thornburrow Drive, Hartshill, Stoke on Trent, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Bridgman
authors.affiliation: Department of Musculoskeletal Disorders Faculty of Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy; Centre for Sports and Exercise Medicine Barts and London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: Nicola
authors.initials: N
authors.lastname: Maffulli
keywords: ACL MRI; MRI; anterior cruciate ligament; knee arthroscopy; volume sequences