C184 Poster Presentations
a selective evaluation of the outer layer of the membrane wasdone. The ROIs were the lateral and medial suprapatellar bursaand the lateral and medial recess. A grading system was alsodeveloped: at each ROI, synovial thickness severity was gradedfrom 0 to 3, giving a global knee score of 0-12.A validation study was carried out with a cohort of 27 knee OApatients. MRIs were evaluated twice at two-week intervals, withthe randomization list changed each time.Results: The MRI sequence reading included a localization ofthe synovial liquid, in the images of a fast multiplanar spoiledgradient-recalled acquisition in the steady-state T2-weighted se-quence, allowing the localization and measurement of the syn-ovial membrane at the corresponding location in the images ofa GRE sequence. The acquisitions were performed in an axialplane without contrast agent.Evaluation of the synovial membrane thickness for the 27 OApatients showed a grade of 1.90.5 (meanSD) with a scoreof 7.12.3, and an intrareader coefcient of 0.92 (p
Osteoarthritis and Cartilage Vol. 15, Supplement C C185
cartilage abnormalities over the LFC may be due to the shallowand small lateral tibial plateau. As the knee is deeply exed,the shallow posterior superior surface of the lateral tibial plateaucould impinge on the far posterior portion of the femoral condyleearlier on the lateral side than on the medial side. Far posteriorarticular cartilage abnormalities may be correlated with differentknee movement and morphology between the medial and lateraltibiofemoral compartments.
331FULLY AUTOMATIC QUANTIFICATION OF KNEEOSTEOARTHRITIS SEVERITY ON STANDARDRADIOGRAPHS BY A NOVEL COMPUTER ASSISTEDSYSTEMH. Oka, N. Yoshimura, S. Muraki, A. Mabuchi, K. Nakamura,H. Kawaguchi22nd Century Medical Center, and Sensory & Motor SystemMedicine, University of Tokyo, Tokyo, Japan
Purpose: Although radiographs are still considered the goldenstandard to evaluate the structural OA severity in clinical practice,the conventional categorical grading by the Kellgren/Lawrence(K/L) system or the OARSI radiographic atlas remains limited inreproducibility and reliability. Here we report a novel computerprogram called KOACAD (knee OA computer-aided diagnosis)which for the rst time realized a fully automatic measurement ofthe six major parameters of knee OA on standard radiographs:medial & lateral minimum JSW (mJSW), medial & lateral jointspace area (JSA), osteophyte area (OPA), and tibiofemoral angle(TFA). This study examined the reproducibility and reliabilityof KOACAD, and further investigated the association of theparameters with knee pain using a large-scale database of theROAD (Research on Osteoarthritis Against Disability) study.Methods: The KOACAD was programmed to perform the follow-ing operations automatically on AP knee radiographs obtainedas a DICOM le. The medial and lateral JSAs were determinedas the area between the outlines of femoral condyle and tibialplateau. The minimum axial distances in the areas were mea-sured as medial and lateral JSWs. OPA and TFA were alsocalculated from the outlines of femur and tibia. The reproducibil-ity of the KOACAD parameters with various knee exion angles(0-30 degrees) and X-ray beam angulations (0-15 degrees) wasevaluated by an intraclass coefcient of correlation (ICC) on ra-diographs of 20 individuals taken with a 2-week interval. Inter-and intraobserver variabilities were determined by value or ICCon 50 randomly selected radiographs. Correlations of sex, age,and the KOACAD parameters with knee pain were examined on1,979 radiographs by a stepwise logistic regression analysis.Results: Since the reproducibility of all KOACAD parameterswas highly maintained with 0 degree knee exion and 0-5 de-gree X-ray beam angulation (ICC=0.88-0.99), it was decided totake radiographs with the knee extended and a horizontal X-raybeam. Although inter- and intraobserver variabilities were highby K/L grading (=0.76 and 0.84), OARSI grading (