Yuxi Pang1. 1. Department of Radiology, University of Michigan, Ann Arbor, Michigan.
Abstract
PURPOSE: MR R2 imaging of ordered tissue exhibits the magic angle effect, potentially masking subtle pathological changes in cartilage. This work aimed to develop an orientation-independent order parameter (S) exclusively sensitive to collagen degeneration. METHODS: A theory was developed based on R 1 ρ dispersion coupled with a simplified molecular motion model in which anisotropic R 2 a ( θ ) became directly proportional to correlation time τ b θ and S could be derived. This new parameter was validated with ex vivo R 1 ρ dispersion reported on orientated (n = 4), enzymatically depleted bovine cartilage (n = 6), and osteoarthritic human knee specimens (n = 14) at 9.4 Tesla, which was further demonstrated on 1 healthy human knee in vivo at 3 Tesla. RESULTS: τ b θ from orientation-dependent R 1 ρ dispersion revealed a significantly high average correlation (r = 0.89 ± 0.05, P < 0.05) with R 2 a (θ) on cartilage samples and a moderate correlation (r = 0.48, P < 0.001) for the human knee in vivo. The derived S (10-3 ) significantly decreased in advanced osteoarthritis (1.64 ± 0.03 vs. 2.30 ± 0.11, P < 0.001) and collagen-depleted samples (1.30 ± 0.11 vs. 2.12 ± 0.12, P < 0.001) when compared with early osteoarthritis and the control, respectively. CONCLUSION: The proposed order parameter could be a potentially useful orientation-independent MR biomarker for collagen alterations in cartilage and other highly structured tissues.
PURPOSE: MR R2 imaging of ordered tissue exhibits the magic angle effect, potentially masking subtle pathological changes in cartilage. This work aimed to develop an orientation-independent order parameter (S) exclusively sensitive to collagen degeneration. METHODS: A theory was developed based on R 1 ρ dispersion coupled with a simplified molecular motion model in which anisotropic R 2 a ( θ ) became directly proportional to correlation time τ b θ and S could be derived. This new parameter was validated with ex vivo R 1 ρ dispersion reported on orientated (n = 4), enzymatically depleted bovine cartilage (n = 6), and osteoarthritic human knee specimens (n = 14) at 9.4 Tesla, which was further demonstrated on 1 healthy human knee in vivo at 3 Tesla. RESULTS: τ b θ from orientation-dependent R 1 ρ dispersion revealed a significantly high average correlation (r = 0.89 ± 0.05, P < 0.05) with R 2 a (θ) on cartilage samples and a moderate correlation (r = 0.48, P < 0.001) for the human knee in vivo. The derived S (10-3 ) significantly decreased in advanced osteoarthritis (1.64 ± 0.03 vs. 2.30 ± 0.11, P < 0.001) and collagen-depleted samples (1.30 ± 0.11 vs. 2.12 ± 0.12, P < 0.001) when compared with early osteoarthritis and the control, respectively. CONCLUSION: The proposed order parameter could be a potentially useful orientation-independent MR biomarker for collagen alterations in cartilage and other highly structured tissues.
Authors: Garry E Gold; Eric Han; Jeff Stainsby; Graham Wright; Jean Brittain; Christopher Beaulieu Journal: AJR Am J Roentgenol Date: 2004-08 Impact factor: 3.959
Authors: Yuxi Pang; Riann M Palmieri-Smith; Dariya I Malyarenko; Scott D Swanson; Thomas L Chenevert Journal: Magn Reson Med Date: 2019-02-22 Impact factor: 4.668
Authors: Sarma V S Akella; Ravinder R Regatte; Andrew J Wheaton; Arijitt Borthakur; Ravinder Reddy Journal: Magn Reson Med Date: 2004-11 Impact factor: 4.668
Authors: U Duvvuri; A D Goldberg; J K Kranz; L Hoang; R Reddy; F W Wehrli; A J Wand; S W Englander; J S Leigh Journal: Proc Natl Acad Sci U S A Date: 2001-10-16 Impact factor: 11.205