Nissi Mikko J, Salo Elli-Noora, Tiitu Virpi, Liimatainen Timo, Michaeli Shalom, Mangia Silvia, Ellermann Jutta, Nieminen Miika T
Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
Research Unit of Medical Imaging, Physics, and Technology, University of Oulu, Oulu, Finland.
J Orthop Res. 2016 Jul;34(7):1111-20. doi: 10.1002/jor.23127. Epub 2015 Dec 31.
Several laboratory and rotating frame quantitative MRI parameters were evaluated and compared for detection of changes in articular cartilage following selective enzymatic digestion. Bovine osteochondral specimens were subjected to 44 h incubation in control medium or in collagenase or chondroitinase ABC to induce superficial collagen or proteoglycan (glycosaminoglycan) alterations. The samples were scanned at 9.4 T for T1 , T1 Gd (dGEMRIC), T2 , adiabatic T1 ρ , adiabatic T2 ρ , continuous-wave T1 ρ , TRAFF2 , and T1 sat relaxation times and for magnetization transfer ratio (MTR). For reference, glycosaminoglycan content, collagen fibril orientation and biomechanical properties were determined. Changes primarily in the superficial cartilage were noted after enzymatic degradation. Most of the studied parameters were sensitive to the destruction of collagen network, whereas glycosaminoglycan depletion was detected only by native T1 and T1 Gd relaxation time constants throughout the tissue and by MTR superficially. T1 , adiabatic T1 ρ , adiabatic T2 ρ , continuous-wave T1 ρ , and T1 sat correlated significantly with the biomechanical properties while T1 Gd correlated with glycosaminoglycan staining. The findings indicated that most of the studied MRI parameters were sensitive to both glycosaminoglycan content and collagen network integrity, with changes due to enzymatic treatment detected primarily in the superficial tissue. Strong correlation of T1 , adiabatic T1ρ , adiabatic T2 ρ , continuous-wave T1 ρ , and T1 sat with the altered biomechanical properties, reflects that these parameters were sensitive to critical functional properties of cartilage. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1111-1120, 2016.
评估并比较了几种实验室和旋转框架定量MRI参数,以检测选择性酶消化后关节软骨的变化。将牛骨软骨标本在对照培养基中或在胶原酶或软骨素酶ABC中孵育44小时,以诱导表面胶原或蛋白聚糖(糖胺聚糖)改变。在9.4T下对样品进行扫描,测量T1、T1 Gd(dGEMRIC)、T2、绝热T1ρ、绝热T2ρ、连续波T1ρ、TRAFF2和T1 sat弛豫时间以及磁化转移率(MTR)。作为参考,测定了糖胺聚糖含量、胶原纤维取向和生物力学性能。酶降解后主要在表层软骨中观察到变化。大多数研究参数对胶原网络的破坏敏感,而糖胺聚糖的消耗仅通过整个组织的天然T1和T1 Gd弛豫时间常数以及表层的MTR检测到。T1、绝热T1ρ、绝热T2ρ、连续波T1ρ和T1 sat与生物力学性能显著相关,而T1 Gd与糖胺聚糖染色相关。研究结果表明,大多数研究的MRI参数对糖胺聚糖含量和胶原网络完整性均敏感,酶处理引起的变化主要在表层组织中检测到。T1、绝热T1ρ、绝热T2ρ、连续波T1ρ和T1 sat与改变的生物力学性能之间的强相关性,反映出这些参数对软骨的关键功能特性敏感。©2015骨科研究协会。由Wiley Periodicals, Inc.出版。《矫形外科学研究》34:1111 - 1120,2016年。