title: Multi-echo GRE imaging of knee cartilage.
abstract: To visualize healthy and abnormal articular cartilage, we investigated the potential of using the 3D multi-echo gradient echo (GRE) signal's magnitude and frequency and maps of T2* relaxation.
  
  
  
  After optimizing imaging parameters in five healthy volunteers, 3D multi-echo GRE magnetic resonance (MR) images were acquired at 3T in four patients with chondral damage prior to their arthroscopic surgery. Average magnitude and frequency information was extracted from the GRE images, and T2* maps were generated. Cartilage abnormalities were confirmed after arthroscopy and were graded using the Outerbridge classification scheme. Regions of interest were identified on average magnitude GRE images and compared to arthroscopy.
  
  
  
  All four patients presented with regions of Outerbridge Grade I and II cartilage damage on arthroscopy. One patient had Grade III changes. Grade I, II, and III changes were detectable on average magnitude and T2* maps, while Grade II and higher changes were also observable on MR frequency maps. For average magnitude images of healthy volunteers, the signal-to-noise ratio of the magnitude image averaged over three echoes was 4.26 ± 0.32, 12.26 ± 1.09, 14.31 ± 1.93, and 13.36 ± 1.13 in bone, femoral, tibial, and patellar cartilage, respectively.
  
  
  
  This proof-of-principle study demonstrates the feasibility of using different imaging contrasts from the 3D multi-echo GRE scan to visualize abnormalities of the articular cartilage. © 2016 International Society for Magnetic Resonance in Medicine Level of Evidence: 1 J. MAGN. RESON. IMAGING 2017;45:1502-1513.
authors: UBC MRI Research Centre, University of British Columbia, Vancouver, Canada.|Department of Pediatrics, University of British Columbia, Vancouver, Canada.|Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
authors: Joanna
authors: 0000-0002-8964-5715
authors: J
authors: Yuen
authors: Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
authors: Jachin
authors: J
authors: Hung
authors: UBC MRI Research Centre, University of British Columbia, Vancouver, Canada.|Department of Pediatrics, University of British Columbia, Vancouver, Canada.|Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
authors: Vanessa
authors: V
authors: Wiggermann
authors: High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
authors: Simon D
authors: SD
authors: Robinson
authors: Department of Orthopaedics, University of British Columbia, Vancouver, Canada.
authors: Robert
authors: R
authors: McCormack
authors: Department of Mechanical Engineering, University of British Columbia, Vancouver, Canada.|Centre for Hip Health and Mobility, University of British Columbia, Vancouver, Canada.|Child and Family Research Institute, University of British Columbia, Vancouver, Canada.
authors: Agnes G
authors: AG
authors: d'Entremont
authors: UBC MRI Research Centre, University of British Columbia, Vancouver, Canada.|Department of Pediatrics, University of British Columbia, Vancouver, Canada.|Child and Family Research Institute, University of British Columbia, Vancouver, Canada.
authors: Alexander
authors: A
authors: Rauscher
mesh_terms: D001182:Arthroscopy; D002357:Cartilage Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D021621:Imaging, Three-Dimensional; D007717:Knee / Q000000981:diagnostic imaging / Q000473:pathology; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009985:Orthopedics / Q000379:methods; D012720:Severity of Illness Index; D059629:Signal-To-Noise Ratio; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: chondral damage; frequency; gradient echo