Bolbos R I, Zuo Jin, Banerjee Suchandrima, Link Thomas M, Ma C Benjamin, Li Xiaojuan, Majumdar Sharmila
Musculoskeletal Quantitative Imaging Research, Department of Radiology, University of California San Francisco, San Francisco, CA 94107, USA.
Osteoarthritis Cartilage. 2008 Oct;16(10):1150-9. doi: 10.1016/j.joca.2008.02.018. Epub 2008 Apr 2.
To evaluate trabecular bone structure in relationship with cartilage parameters in distal femur and proximal tibia of the human knee at 3Tesla (3T) using high-resolution magnetic resonance imaging (MRI) with parallel imaging.
Sixteen healthy controls and 16 patients with mild osteoarthritis (OA) were studied using a 3T magnetic resonance (MR) scanner and an eight-channel phased-array knee coil. Axial 3D GeneRalized Autocalibrating Partially Parallel Acquisition (GRAPPA)-based phase cycled Fast Imaging Employing Steady State Acquisition (FIESTA-c) images were acquired in order to quantify the trabecular bone structure. For assessing cartilage morphology (thickness, volume), sagittal high-resolution 3D spoiled gradient echo (SPGR) images were acquired. In a subset of the subjects, sagittal images were acquired for measuring T1rho and T2 relaxation times, using 3D T1rho and T2 mapping techniques.
Good measurement reproducibility was observed for bone parameters, the coefficients of variations (CVs) ranging from 1.8% for trabecular number (app. Tb.N) to 5.5% for trabecular separation (app. Tb.Sp). Significant differences between control and OA groups were found for bone volume fraction bone volume over total volume (app. BV/TV) and app. Tb.Sp in all compartments. Significantly increased values in T1rho and T2 were demonstrated in OA patients compared with controls at the femur, but not at the tibia. T1rho was negatively correlated with app. BV/TV, app. Tb.N and app. Tb.Sp both at the medial femoral condyle (MFC) and lateral tibia (LT), while T2 was only correlated at the LT. Also, medial tibia (MT) T1rho was negatively correlated with app. BV/TV (R(2)=-0.49, P<0.05) and app. Tb.N (R(2)=-0.42, P<0.05) from the opposite side of lateral femoral condyle (LFC). Significant correlations were found between trabecular bone parameters and cartilage thickness and normalized volume, mainly at LT, tibia (T) and femur (F).
At this early stage of OA, an overall decrease in bone structure parameters and an increase in cartilage parameters (T1rho, T2) were noticed in patients. Trabecular bone structure correlated with articular cartilage parameters suggesting that loss of mineralized bone is associated with cartilage degeneration.
使用并行成像的高分辨率磁共振成像（MRI），在3特斯拉（3T）条件下评估人膝关节股骨远端和胫骨近端的小梁骨结构与软骨参数之间的关系。
使用3T磁共振（MR）扫描仪和八通道相控阵膝关节线圈对16名健康对照者和16名轻度骨关节炎（OA）患者进行研究。采集基于轴向三维广义自校准部分并行采集（GRAPPA）的相位循环稳态采集快速成像（FIESTA-c）图像，以量化小梁骨结构。为评估软骨形态（厚度、体积），采集矢状面高分辨率三维扰相梯度回波（SPGR）图像。在部分受试者中，使用三维T1rho和T2 mapping技术采集矢状面图像以测量T1rho和T2弛豫时间。
观察到骨参数具有良好的测量重复性，变异系数（CVs）范围从骨小梁数量（约Tb.N）的1.8%到骨小梁间距（约Tb.Sp）的5.5%。在所有区域，对照组和OA组之间在骨体积分数（骨体积与总体积之比，约BV/TV）和约Tb.Sp方面存在显著差异。与对照组相比，OA患者股骨处的T1rho和T2值显著升高，但胫骨处未升高。在内侧股骨髁（MFC）和外侧胫骨（LT）处，T1rho与约BV/TV、约Tb.N和约Tb.Sp均呈负相关，而T2仅在LT处相关。此外，内侧胫骨（MT）的T1rho与外侧股骨髁（LFC）对侧的约BV/TV（R(2)=-0.49，P<0.05）和约Tb.N（R(2)=-0.42，P<0.05）呈负相关。在小梁骨参数与软骨厚度和标准化体积之间发现显著相关性，主要在LT、胫骨（T）和股骨（F）处。
在OA的这一早期阶段，患者出现骨结构参数总体下降和软骨参数（T1rho、T2）升高。小梁骨结构与关节软骨参数相关，提示矿化骨的丢失与软骨退变有关。
