title: Accuracy of model-based tracking of knee kinematics and cartilage contact measured by dynamic volumetric MRI.
abstract: The purpose of this study was to determine the accuracy of knee kinematics and cartilage contact measured by volumetric dynamic MRI. A motor-actuated phantom drove femoral and tibial bone segments through cyclic 3D motion patterns. Volumetric images were continuously acquired using a 3D radially undersampled cine spoiled gradient echo sequence (SPGR-VIPR). Image data was binned based on position measured via a MRI-compatible rotary encoder. High-resolution static images were segmented to create bone models. Model-based tracking was performed by optimally registering the bone models to the volumetric images at each frame of the SPGR-VIPR series. 3D tibiofemoral translations and orientations were reconstructed, and compared to kinematics obtained by tracking fiducial markers. Imaging was repeated on a healthy subject who performed cyclic knee flexion-extension. Cartilage contact for the subject was assessed by measuring the overlap between articular cartilage surfaces. Model-based tracking was able to track tibiofemoral angles and translations with precisions less than 0.8° and 0.5mm. These precisions resulted in an uncertainty of less than 0.5mm in cartilage contact location. Dynamic SPGR-VIPR imaging can accurately assess in vivo knee kinematics and cartilage contact during voluntary knee motion performed in a MRI scanner. This technology could facilitate the quantitative investigation of links between joint mechanics and the development of osteoarthritis.
authors.affiliation: Department of Mechanical Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI 53706, USA.
authors.forename: Jarred
authors.initials: J
authors.lastname: Kaiser
authors.affiliation: Department of Mechanical Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI 53706, USA.
authors.forename: Arezu
authors.initials: A
authors.lastname: Monawer
authors.affiliation: Department of Biomedical Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI 53706, USA.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Chaudhary
authors.affiliation: Department of Medical Physics, University of Wisconsin - Madison, 1111 Highland Avenue, Madison, WI 53705, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Johnson
authors.affiliation: Department of Biomedical Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI 53706, USA ; Department of Medical Physics, University of Wisconsin - Madison, 1111 Highland Avenue, Madison, WI 53705, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Wieben
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, 600 Highland Avenue, Madison, WI 53792, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Kijowski
authors.affiliation: Department of Mechanical Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI 53706, USA ; Department of Biomedical Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI 53706, USA ; Department of Orthopedics and Rehabilitation, University of Wisconsin - Madison, 1685 Highland Avenue, Madison, WI 53705, USA . Electronic address: dgthelen@wisc.edu.
authors.forename: Darryl G
authors.initials: DG
authors.lastname: Thelen
mesh_terms: D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000000981:diagnostic imaging*; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D055595:Mechanical Phenomena; D019047:Phantoms, Imaging
keywords: Biomechanics; Dynamic MRI; Knee kinematics; Validation