title: Relationship between T1rho magnetic resonance imaging, synovial fluid biomarkers, and the biochemical and biomechanical properties of cartilage.
abstract: Non-invasive techniques for quantifying early biochemical and biomechanical changes in articular cartilage may provide a means of more precisely assessing osteoarthritis (OA) progression. The goals of this study were to determine the relationship between T1rho magnetic resonance (MR) imaging relaxation times and changes in cartilage composition, cartilage mechanical properties, and synovial fluid biomarker levels and to demonstrate the application of T1rho imaging to evaluate cartilage composition in human subjects in vivo. Femoral condyles and synovial fluid were harvested from healthy and OA porcine knee joints. Sagittal T1rho relaxation MR images of the condyles were acquired. OA regions of OA joints exhibited an increase in T1rho relaxation times as compared to non-OA regions. Furthermore in these regions, cartilage sGAG content and aggregate modulus decreased, while percent degraded collagen and water content increased. In OA joints, synovial fluid concentrations of sGAG decreased and C2C concentrations increased compared to healthy joints. T1rho relaxation times were negatively correlated with cartilage and synovial fluid sGAG concentrations and aggregate modulus and positively correlated with water content and permeability. Additionally, we demonstrated the application of these in vitro findings to the study of human subjects. Specifically, we demonstrated that walking results in decreased T1rho relaxation times, consistent with water exudation and an increase in proteoglycan concentration with in vivo loading. Together, these findings demonstrate that cartilage MR imaging and synovial fluid biomarkers provide powerful non-invasive tools for characterizing changes in the biochemical and biomechanical environments of the joint.
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Courtney C
authors.initials: CC
authors.lastname: Hatcher
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Amber T
authors.initials: AT
authors.lastname: Collins
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Sophia Y
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Lindsey C
authors.initials: LC
authors.lastname: Michel
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Mostertz
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Sophia N
authors.initials: SN
authors.lastname: Ziemian
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Spritzer
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Farshid
authors.initials: F
authors.lastname: Guilak
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Louis E
authors.initials: LE
authors.lastname: DeFrate
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA. Electronic address: alr@duke.edu.
authors.forename: Amy L
authors.initials: AL
authors.lastname: McNulty
mesh_terms: D000328:Adult; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D003094:Collagen / Q000378:metabolism; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D055595:Mechanical Phenomena; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D011509:Proteoglycans / Q000378:metabolism; D013552:Swine; D013582:Synovial Fluid / Q000378:metabolism*; D014867:Water / Q000378:metabolism
chemical_list: D015415:Biomarkers; D011509:Proteoglycans; D014867:Water; D003094:Collagen
keywords: Biomarkers; Imaging; MRI; Modulus; T2 mapping