Aro Olli-Pekka, Casula Victor, Hänninen Nina E, Karjalainen Jouni, Nissi Mikko J, Nieminen Miika T, Henschel Henning
Research Unit of Health Sciences and Technology, University of Oulu, Oulu, Finland.
Department of Technical Physics, University of Eastern Finland, Kuopio, Finland.
Heliyon. 2025 Jan 13;11(2):e41854. doi: 10.1016/j.heliyon.2025.e41854. eCollection 2025 Jan 30.
To elucidate the connection between MRI relaxation properties of articular cartilage and tissue composition, in terms of collagen and chondroitin sulfate (CS). Additional aims were to determine the effect of different magnetic field strengths, as well as the effect of concentrations of the components on relaxation properties.
A series of MRI phantoms consisting of gels containing collagen and chondroitin sulfate were prepared with final concentrations of collagen in the range 20-60 mg/g and the CS concentration in the range 0-40 mg/g. (= 1/ ) and (= 1/ ) values of the phantoms were measured at three different MRI field strengths (1.5, 3.0 and 9.4 T), (= 1/ ) values were measured at 9.4 T.
Relaxation rates generally increased with increasing concentration of either of the compounds. values generally increased with CS, and at clinically used magnetic fields, namely 1.5 T and 3.0 T, with collagen concentration. At 9.4 T, values also showed an increase with collagen concentration that could not be clearly identified at lower field strengths. values increased with both collagen and CS concentration but the amplitude of the spin-lock pulse only had a limited effect on relaxation rates above 100 Hz.
Our results suggest that , , and are modulated by collagen and CS concentrations, with collagen likely dominating at physiological concentrations.
从胶原蛋白和硫酸软骨素（CS）方面阐明关节软骨的MRI弛豫特性与组织组成之间的联系。其他目的是确定不同磁场强度的影响，以及各成分浓度对弛豫特性的影响。
制备了一系列由含有胶原蛋白和硫酸软骨素的凝胶组成的MRI体模，胶原蛋白的最终浓度范围为20 - 60 mg/g，CS浓度范围为0 - 40 mg/g。在三种不同的MRI场强（1.5、3.0和9.4 T）下测量体模的（= 1/）和（= 1/）值，在9.4 T下测量（= 1/）值。
弛豫率通常随两种化合物中任一种浓度的增加而增加。值通常随CS增加，并且在临床使用的磁场即1.5 T和3.0 T下，随胶原蛋白浓度增加。在9.4 T时，值也随胶原蛋白浓度增加，而在较低场强下无法明确识别这种增加。值随胶原蛋白和CS浓度均增加，但自旋锁定脉冲的幅度仅对高于100 Hz的弛豫率有有限影响。
我们的结果表明，、和受胶原蛋白和CS浓度调节，在生理浓度下胶原蛋白可能起主导作用。
