Chemical exchange in knee cartilage assessed by R1ρ (1/T1ρ) dispersion at 3 T
Chemical exchange in knee cartilage assessed by R1ρ (1/T1ρ) dispersion at 3 T
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DOI：
10.1016/j.mri.2014.07.008
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发表时间：
2015-01-01
影响因子：
2.5
通讯作者：
Gore, John C.
中科院分区：
文献类型：
--
作者：
Wang, Ping;Block, Jake;Gore, John C.
目的：用R-1 rho离散度分析方法定量研究膝关节软骨中质子化学交换的特征。材料和方法：6名健康受试者（1名女性和5名男性，年龄范围24至71岁）在3 T MRI扫描仪上进行了膝关节软骨的T-1 rho成像。R-1 rho（= 1/T-1 rho）的定量估计是使用5种不同的自旋锁持续时间为12个不同的自旋锁幅度在0至550 Hz的范围内。当R-1 ρ随自旋锁定强度的变化（R-1 ρ色散）由化学交换贡献主导时，可以分析R-1 ρ色散曲线以导出交换的定量特征并提供关于组织组成的信息。在这项工作中，在体内的R-1 rho分散的人膝关节软骨在3 T的分析，和质子之间的交换率的水和大分子羟基（主要在糖胺聚糖中）基于理论模型进行估计。R-1 rho值在关节软骨中显示出明显的分散性，并且在锁定场的低值和高值之间变化约50%，这种变化比周围组织中的变化大得多，这与化学交换的贡献更大相一致。根据理论模型，软骨中的交换率估计在1.0-3.0 kHz的范围内，并且在组织内变化。在一个单一的膝关节的变化似乎是随着年龄的增长。结论：R-1 rho离散度分析可以提供更具体的信息，研究软骨生化成分和形成的基础上，定量评价软骨疾病。(C)2014年爱思唯尔公司All rights reserved.
Purpose: To quantify the characteristics of proton chemical exchange in knee cartilage in vivo by R-1 rho dispersion analysis.Materials and methods: Six healthy subjects (one female and five males, age range 24 to 71 y) underwent T-1 rho, imaging of knee cartilage on a 3 T MRI scanner. Quantitative estimates of R-1 rho (= 1/T-1 rho) were made using 5 different spin-lock durations for each of 12 different spin-lock amplitudes over the range 0 to 550 Hz. When the variations of R-1 rho with spin-locking strength (the R-1 rho dispersion) are dominated by chemical exchange contributions, R-1 rho dispersion curves can be analyzed to derive quantitative characteristics of the exchange and provide information on tissue composition. In this work, in vivo R-1 rho dispersion of human knee articular cartilage at 3 T was analyzed, and the exchange rates of protons between water and macromolecular hydroxyls (mainly in glycosaminoglycans) were estimated based on a theoretical model.Results: R-1 rho values showed marked dispersion in articular cartilage and varied by approximately 50% between low and high values of the locking field, a change much greater than in surrounding tissues, consistent with greater contributions from chemical exchange. From the theoretical model, the exchange rates in cartilage were estimated to be in the range of 1.0-3.0 kHz, and varied within the tissue. Variations within a single knee appear to be larger with increasing age.Conclusion: R-1 rho dispersion analysis may provide more specific information for studying cartilage biochemical composition and form the basis for quantitative evaluation of cartilage disorders. (C) 2014 Elsevier Inc. All rights reserved.