Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.
Center for Digital Health Innovation, University of California, San Francisco, San Francisco, California, USA.
Magn Reson Med. 2022 Feb;87(2):733-745. doi: 10.1002/mrm.29024. Epub 2021 Sep 30.
To validate the potential of quantifying R -R using one pair of signals with T preparation and T preparation incorporated to magnetization-prepared angle-modulated partitioned k-space spoiled gradient-echo snapshots (MAPSS) acquisition and to find an optimal preparation time (T ) for in vivo knee MRI.
Bloch equation simulations were first performed to assess the accuracy of quantifying R -R using T - and T -prepared signals with an equivalent T . For validation of this technique in comparison to the conventional approach that calculates R -R after estimating both T and T , phantom experiments and in vivo validation with five healthy subjects and five osteoarthritis patients were performed at a clinical 3T scanner.
Bloch equation simulations demonstrated that the accuracy of this efficient R -R quantification method and the optimal T can be affected by image signal-to-noise ratio (SNR) and tissue relaxation times, but quantification can be closest to the reference with an around 25 ms T for knee cartilage. Phantom experiments demonstrated that the proposed method can depict R -R changes with agarose gel concentration. With in vivo data, significant correlation was observed between cartilage R -R measured from the conventional and the proposed methods, and a T of 25.6 ms provided the most agreement by Bland-Altman analysis. R -R was significantly lower in patients than in healthy subjects for most cartilage compartments.
As a potential biomarker to indicate cartilage degeneration, R -R can be efficiently measured using one pair of T -prepared and T -prepared signals with an optimal T considering cartilage relaxation times and image SNR.
验证使用一对带有 T 准备和 T 准备的信号来量化 R -R 的可能性，将 T 准备和 T 准备合并到磁化准备的角度调制分区 k 空间激发梯度回波快照（MAPSS）采集，以及找到用于体内膝关节 MRI 的最佳准备时间（T ）。
首先进行布洛赫方程模拟，以评估使用具有等效 T 的 T -和 T -准备信号量化 R -R 的准确性。为了将这种技术与传统方法进行比较，该方法在估计 T 和 T 之后计算 R -R ，在临床 3T 扫描仪上进行了体模实验和五名健康受试者和五名骨关节炎患者的体内验证。
布洛赫方程模拟表明，这种高效 R -R 量化方法的准确性和最佳 T 可以受到图像信噪比（SNR）和组织弛豫时间的影响，但通过大约 25 ms 的 T 进行量化可以最接近参考值对于膝关节软骨。体模实验表明，该方法可以描绘琼脂糖凝胶浓度的 R -R 变化。通过体内数据，从传统方法和提出的方法测量的软骨 R -R 之间观察到显著相关性，Bland-Altman 分析表明 25.6 ms 的 T 提供了最一致的结果。与健康受试者相比，大多数软骨间隙中的患者的 R -R 明显降低。
作为一种指示软骨退变的潜在生物标志物，考虑到软骨弛豫时间和图像 SNR，可以使用一对带有 T 准备和 T 准备的信号来高效测量 R -R ，并使用最佳 T 。
