Namiranian Behnam, Jerban Saeed, Ma Yajun, Dorthe Erik W, Masoud-Afsahi Amir, Wong Jonathan, Wei Zhao, Chen Yanjun, D'Lima Darryl, Chang Eric Y, Du Jiang
Department of Radiology, University of California San Diego, San Diego, CA 92093, USA.
Department of Radiology, University of California San Diego, San Diego, CA 92093, USA.
J Biomech. 2020 Dec 2;113:110085. doi: 10.1016/j.jbiomech.2020.110085. Epub 2020 Oct 24.
Conventional magnetic resonance imaging (MRI) is not capable of detecting signal from the deep cartilage due to its short transverse relaxation time (T2). Moreover, several quantitative MRI techniques are significantly influenced by the magic angle effect. The combinations of ultrashort echo time (UTE) MRI with magnetization transfer (UTE-MT) and Adiabatic T (UTE-AdiabT) imaging allow magic angle-insensitive assessments of all regions of articular cartilage. The purpose of this study was to investigate the correlations between quantitative three-dimensional UTE MRI biomarkers and mechanical properties of human tibiofemoral cartilage specimens. In total, 40 human tibiofemoral cartilage specimens were harvested from three male and four female donors (64 ± 18 years old). Cartilage samples were scanned using a series of quantitative 3D UTE Cones T* (UTE-T*), T (UTE-T), UTE-AdiabT, and UTE-MT sequences in a standard knee coil on a clinical 3T scanner. UTE-MT data were acquired with a series of MT powers and frequency offsets to calculate magnetization transfer ratio (MTR), as well as macromolecular fraction (MMF) and macromolecular T (Tmm) through modeling. Cartilage stiffness and Hayes elastic modulus were measured using indentation tests. Correlations of 3D UTE Cones MRI measurements in the superficial layer, deep layer, and global regions of interest (ROIs) with mechanical properties were investigated. Cartilage mechanical properties demonstrated highest correlations with UTE measures of the superficial layer of cartilage. AdiabT, MTR, and MMF in superficial layer ROIs showed significant correlations with Hayes elastic modulus (p < 0.05, R = -0.54, 0.49, and 0.66, respectively). These UTE measures in global ROIs showed significant, though slightly lower, correlations with Hayes elastic modulus (p < 0.05, R = -0.37, 0.52, and 0.60, respectively). Correlations between other UTE MRI measurements (T*, T, and Tmm) and mechanical properties were non-significant. The 3D UTE-AdiabT and UTE-MT sequences were highlighted as promising surrogates for non-invasive assessment of cartilage mechanical properties. MMF from UTE-MT modeling showed the highest correlations with cartilage mechanics.
传统磁共振成像（MRI）由于深层软骨的横向弛豫时间（T2）较短，无法检测到其信号。此外，几种定量MRI技术受到魔角效应的显著影响。超短回波时间（UTE）MRI与磁化传递（UTE-MT）和绝热T（UTE-AdiabT）成像的结合，能够对关节软骨的所有区域进行不受魔角影响的评估。本研究的目的是探讨定量三维UTE MRI生物标志物与人类胫股关节软骨标本力学性能之间的相关性。总共从3名男性和4名女性捐赠者（64±18岁）身上获取了40个人类胫股关节软骨标本。使用一系列定量3D UTE圆锥T*（UTE-T*）、T（UTE-T）、UTE-AdiabT和UTE-MT序列，在临床3T扫描仪的标准膝关节线圈中对软骨样本进行扫描。通过一系列MT功率和频率偏移获取UTE-MT数据，以计算磁化传递率（MTR），并通过建模计算大分子分数（MMF）和大分子T（Tmm）。使用压痕试验测量软骨硬度和海斯弹性模量。研究了三维UTE圆锥MRI在表层、深层和整体感兴趣区域（ROI）的测量值与力学性能之间的相关性。软骨力学性能与软骨表层的UTE测量值相关性最高。表层ROI中的AdiabT、MTR和MMF与海斯弹性模量显著相关（p<0.05，R分别为-0.54、0.49和0.66）。整体ROI中的这些UTE测量值与海斯弹性模量也显著相关，尽管相关性略低（p<0.05，R分别为-0.37、0.52和0.60）。其他UTE MRI测量值（T*、T和Tmm）与力学性能之间的相关性不显著。三维UTE-AdiabT和UTE-MT序列被视为无创评估软骨力学性能的有前景的替代方法。UTE-MT建模得到的MMF与软骨力学的相关性最高。
