Ultrasonographic evaluation of meniscal extrusion: comparison with magnetic resonance imaging assessment

s / Osteoarthritis and Cartilage 21 (2013) S63–S312 S186 subjects that developed pain over 7 years had greater baseline cartilage WORMS scores than subjects that did not develop pain (Figure 1). These associations were significant for the medial femur (adjusted OR 1⁄4 1.42, p1⁄4 0.041, CI1⁄4 1.01-2.00) and the patella (adjusted OR1⁄4 1.94, p1⁄4 0.002, CI 1⁄4 1.27-2.96). Similar trends were observed in the lateral tibia (adjusted OR 1⁄4 1.39, p 1⁄4 0.054, CI 1⁄4 0.99-1.97), lateral femur (adjusted OR 1⁄4 1.39 p 1⁄4 0.099 CI 1⁄4 0.99 1.97) and medial tibia (adjusted OR 1⁄4 1.82, p1⁄4 0.057, CI1⁄4 0.98 3.37). No significant associationwas observed between either baseline bone marrow edema pattern or meniscus lesion score and the development of pain. Conclusions: This study demonstrated that elevated mean T2 and increased severity of cartilage lesions at baseline was predictive of the development of knee pain over 7 years. This study highlights the potentially important role of cartilage matrix composition and morphology in the development of symptomatic OA in subjects with risk factors for the disease. 354 EVALUATION OF T1r RELAXATION TIMES IN MENISCAL TEARS DURING STATIC LOADING J. Singh, J. Schooler, D. Kumar, K. Subburaj, L. Nardo, K.B. Stiers, X. Li, R.B. Souza, T.M. Link, S. Majumdar. Musculoskeletal Quantitative Imaging Research, Department of Radiology and Biomedical Imaging; Univ. of California, San Fancisco, San Francisco, CA, USA Purpose: Among its many functions, the meniscus serves to evenly distribute the load of the body and provide a smooth surface for knee joint articulation. The properties of the menisci are based on its biochemical composition which includes water, collagen and proteoglycan (PG). Previous studies have foundmeniscal tears to be associated with symptomatic osteoarthritis (OA) and articular cartilage loss. Thus the health of the meniscus may play an important role in the progression in OA of the knee joint. Magnetic resonance imaging techniques such as T1r relaxation time mapping allows for non-invasive quantification of the biochemical composition of joint tissues and has been used to detect degenerative changes. Meniscal tears are characterized by damage to collagen fibrils and the PG matrix and are most commonly seen in the posterior horn of the medial meniscus in osteoarthritic knees. Recent studies have reported elevated T1r values inmenisci with tears compared to healthy controls and we hypothesize loading may provide additional information on meniscal health. The purpose of this investigation was to evaluate the biochemical relationship between healthy and diseased menisci as measured by T1r relaxation under static loading conditions. Methods: MR data for 38 subjects (age: 53.6 10.1 years, BMI: 25.7 8.2 kg/m2, 50% female) were acquired on a 3T MR scanner with an 8channel phased array knee coil using a custom-built loading apparatus. Figure 1. Images A,B,C show PHMED of meniscus with meniscal WORMS grade 0 on a 3D FSE CUBE (A) and the representative color overlay of T1 p relaxation time superimposed upon the T1 p weighted first echo (TSL1⁄40) under unloaded (B) and loaded (C) conditions. Images D,E,F show PHMED of meniscus with meniscal WORMS grade 2 (horizontal tear) on a 3D FSE CUBE (D) and the representative color overlay of T1 p relaxation time superimposed upon the T1 p weighted first echo (TSL1⁄40) under unloaded (E) and loaded (F) conditions. Qualitative observation displays a marked increased in T1p relaxation time for PHMED with a tear compared to no tear. MR Images (sagittal T1r and high resolution 3D FSE CUBE)were acquired for subjects with and without an axial load equivalent to 50% body weight. Loaded scans were prospectively registered to unloaded scans using a rigid registration algorithm. Four meniscus compartments (lateral anterior horn (AHLAT), lateral posterior horn (PHLAT), medial anterior horn (AHMED), and medial posterior horn (PHMED)) were segmented on 3D FSE CUBE images and then superimposed upon registered T1r maps to extract relaxation time mean values. Morphological grading using modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) was performed to determine the occurrence of meniscal tears. Subjects were then stratified into no meniscal tear (meniscal grades of 0-1) and meniscal tear (meniscal grade 2-4) groups. Statistical differences between groups in both unloaded and loaded conditions were performed using a linear regression model adjusting for age, BMI and gender in JMP software version 8 (SAS Institute, Cary NC). Results: The incidence of tears in a location other than PHMED (34.2%) was very low and therefore our analysis was focused on the PHMED. Under static loading T1r relaxation times were significantly higher (ΔT1r +4.1ms, P<.05) in PHMEDwith a tear (18.6ms) compared to those without a tear (14.5ms) in PHMED. This same trend was seen between PHMED tear (18.4ms) and no tear (15.3ms) groups in the unloaded condition (ΔT1r +3.1ms, P<.05). There was no significant difference between loaded and unloaded meniscal T1r in tear or no tear groups. Figure 2. Average T1 p values for meniscus medial posterior horn between no tear and tear groups in both unloaded and loaded conditions. Statistical significance of P<.05 is indicated by an asterisk. Conclusions: Meniscal tears had significant effects on T1r values in both unloaded and loaded conditions. Static loading did not have significant effects on T1r values in either meniscal tear or no tear groups compared to unloaded conditions. Unlike hyaline articular cartilage which has been shown to have changes in T1r under loaded conditions, the meniscus is mainly composed of Type 1 collagen which does not easily deform under static loading and may explain why no significant T1r differences were observed under varied loading conditions. Future analysis will incorporate T2 relaxation measures and stratification of subjects based on severities of osteoarthritis to probe how overall joint health may affect meniscus response to acute loading. 355 VALIDATION OF MAGNETIC RESONANCE IMAGING-BASED BONE MORPHOMETRY ASSESSMENTS IN CADAVERIC KNEES J.B. Driban y, M.F. Barbe z, M. Amin z, A.M. Tassinari x, G.H. Lo {,k, L.L. Price y, C.B. Eaton , E. Schneider yy, T.E. McAlindon y. y Tufts Med. Ctr., Boston, MA, USA; z Temple Univ., Philadelphia, PA, USA; xBoston Univ., Boston, MA, USA; kMichael E. DeBakey VAMC, Houston, TX, USA; {Baylor Coll. of Med., Houston, TX, USA; Brown Univ, Pawtucket, RI, USA; yyCleveland Clinic Fndn., Cleveland, OH, USA Purpose: Peri-articular bone changes may provide important insights into the role of bone in osteoarthritis (OA) progression. High-resolution magnetic resonance (MR) imaging can yield estimates of trabecular changes and has good construct validity. However, the validity of MRbased trabecular morphometry compared to a gold standard (e.g., micro-computed tomography [microCT]) remains unknown. In this cadaveric study we explored the association between MR-based and microCT-based trabecular morphometry in the proximal peri-articular medial tibia.