OBJECTIVE: To evaluate the effect of acute loading on healthy and osteoarthritic knee cartilage T(1ρ) and T(2) relaxation times. DESIGN: Twenty subjects with radiographic evidence of osteoarthritis (OA) and 10 age-matched controls were enrolled. Magnetic resonance imaging (MRI) acquisition, including T(1ρ) and T(2) map sequences were performed unloaded and loaded at 50% body mass. Cartilage masks were segmented semi-automatically on registered high-resolution spoiled gradient-echo (SPGR) images for each compartment (medial and lateral). Cartilage lesions were identified using a modified Whole Organ Magnetic Resonance Imaging Score (WORMS) score. Statistical differences were explored using separate two-way (group×loading condition) Analysis of Variance (ANOVA) using age as a covariate to evaluate the effects of loading on T(1ρ) and T(2) relaxation times. RESULTS: A significant decrease in T(1ρ) (44.5±3.8 vs 40.2±4.8ms for unloaded and loaded, respectively; P<0.001) and T(2) (31.8±3.8 vs 30.5±4.8ms for unloaded and loaded, respectively; P<0.001) relaxation times was observed in the medial compartment with loading while no differences were observed in the lateral compartment. This behavior occurred independent of WORMS score. Cartilage compartments with small focal lesions experienced greater T(1ρ) change scores with loading when compared to cartilage without lesions or cartilage with larger defects (P=0.05). CONCLUSIONS: Acute loading resulted in a significant decrease in T(1ρ) and T(2) relaxation times of the medial compartment, with greater change scores observed in cartilage regions with small focal lesions. These data suggest that changes of T(1ρ) values with loading may be related to cartilage biomechanical properties (i.e., tissue elasticity) and may be a valuable tool for the scientist and clinician at identifying early cartilage disease.
OBJECTIVE: To evaluate the effect of acute loading on healthy and osteoarthritic knee cartilage T(1ρ) and T(2) relaxation times. DESIGN: Twenty subjects with radiographic evidence of osteoarthritis (OA) and 10 age-matched controls were enrolled. Magnetic resonance imaging (MRI) acquisition, including T(1ρ) and T(2) map sequences were performed unloaded and loaded at 50% body mass. Cartilage masks were segmented semi-automatically on registered high-resolution spoiled gradient-echo (SPGR) images for each compartment (medial and lateral). Cartilage lesions were identified using a modified Whole Organ Magnetic Resonance Imaging Score (WORMS) score. Statistical differences were explored using separate two-way (group×loading condition) Analysis of Variance (ANOVA) using age as a covariate to evaluate the effects of loading on T(1ρ) and T(2) relaxation times. RESULTS: A significant decrease in T(1ρ) (44.5±3.8 vs 40.2±4.8ms for unloaded and loaded, respectively; P<0.001) and T(2) (31.8±3.8 vs 30.5±4.8ms for unloaded and loaded, respectively; P<0.001) relaxation times was observed in the medial compartment with loading while no differences were observed in the lateral compartment. This behavior occurred independent of WORMS score. Cartilage compartments with small focal lesions experienced greater T(1ρ) change scores with loading when compared to cartilage without lesions or cartilage with larger defects (P=0.05). CONCLUSIONS: Acute loading resulted in a significant decrease in T(1ρ) and T(2) relaxation times of the medial compartment, with greater change scores observed in cartilage regions with small focal lesions. These data suggest that changes of T(1ρ) values with loading may be related to cartilage biomechanical properties (i.e., tissue elasticity) and may be a valuable tool for the scientist and clinician at identifying early cartilage disease.
Authors: K Subburaj; R B Souza; C Stehling; B T Wyman; M-P Le Graverand-Gastineau; T M Link; X Li; S Majumdar Journal: J Orthop Res Date: 2011-12-07 Impact factor: 3.494
Authors: Richard B Souza; Thomas Baum; Samuel Wu; Brian T Feeley; Nancy Kadel; Xiaojuan Li; Thomas M Link; Sharmila Majumdar Journal: J Orthop Sports Phys Ther Date: 2012-03-08 Impact factor: 4.751
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Authors: Karupppasamy Subburaj; Deepak Kumar; Richard B Souza; Hamza Alizai; Xiaojuan Li; Thomas M Link; Sharmila Majumdar Journal: Am J Sports Med Date: 2012-06-22 Impact factor: 6.202
Authors: Richard B Souza; Charles Fang; Anthony Luke; Samuel Wu; Xiaojuan Li; Sharmila Majumdar Journal: Clin Biomech (Bristol, Avon) Date: 2011-11-25 Impact factor: 2.063
Authors: Kevin A Taylor; Amber T Collins; Lauren N Heckelman; Sophia Y Kim; Gangadhar M Utturkar; Charles E Spritzer; William E Garrett; Louis E DeFrate Journal: J Biomech Date: 2018-11-01 Impact factor: 2.712