Association between radiography-based subchondral bone structure and MRI-based cartilage composition in postmenopausal women with mild osteoarthritis. Issue 12 (December 2017) - Hirvasniemi, J.
Summary: Objective: Our aim was to investigate the relation between radiograph-based subchondral bone structure and cartilage composition assessed with delayed gadolinium enhanced magnetic resonance imaging of cartilage (dGEMRIC) and T 2 relaxation time. Design: Ninety-three postmenopausal women (Kellgren–Lawrence grade 0: n = 13, 1: n = 26, 2: n = 54) were included. Radiograph-based bone structure was assessed using entropy of the Laplacian-based image ( E Lap ) and local binary patterns ( E LBP ), homogeneity indices of the local angles (HIAngles, mean, HIAngles, Perp, HIAngles, Paral ), and horizontal (FDHor ) and vertical fractal dimensions (FDVer ). Mean dGEMRIC index and T 2 relaxation time of tibial cartilage were calculated to estimate cartilage composition. Results: HIAngles, mean ( r s = −0.22) and HIAngles, Paral ( r s = −0.24) in medial subchondral bone were related ( P < 0.05) to dGEMRIC index of the medial tibial cartilage. E Lap ( r s = −0.23), FDHor, 0.34 mm ( r = 0.21) and FDVer, 0.68 mm ( r = 0.24) in medial subchondral bone were related ( P < 0.05) to T 2 relaxation time values of the medial tibial cartilage. FDHor at different scales in lateral subchondral bone were related ( P < 0.01) to dGEMRIC index ( r = 0.29–0.41) and T 2 values of lateral tibial cartilage ( r = −0.28 to −0.36). FDVer at larger scales were related ( P < 0.05) to dGEMRIC index ( r = 0.24–0.25) and T 2 values of lateral tibial cartilage ( r = −0.21). HIAngles, Paral ( r = −0.25) and FDVer, 0.68 mm ( r s = 0.22) in the lateral tibial trabecular bone were related ( P < 0.05) to dGEMRIC index of the lateral tibial cartilage. Conclusion: Our results support the presumption that several tissues are affected in the early osteoarthritis (OA). Furthermore, they indicate that the detailed analysis of radiographs may serve as a complementary imaging tool for OA studies.