Knee degeneration involves all the major tissues in the joint. However, conventional MRI sequences can only detect signals from long T2 tissues such as the superficial cartilage, with little signal from the deep cartilage, menisci, ligaments, tendons and bone. It is highly desirable to develop new sequences that can detect signal from all major tissues in the knee. We aimed to develop a comprehensive quantitative three-dimensional ultrashort echo time (3D UTE) cones imaging protocol for a truly "whole joint" evaluation of knee degeneration. The protocol included 3D UTE cones actual flip angle imaging (3D UTE-Cones-AFI) for T1 mapping, multiecho UTE-Cones with fat suppression for T2 * mapping, UTE-Cones with adiabatic T1ρ (AdiabT1ρ ) preparation for AdiabT1ρ mapping, and UTE-Cones magnetization transfer (UTE-Cones-MT) for MT ratio (MTR) and modeling of macromolecular proton fraction (f). An elastix registration technique was used to compensate for motion during scans. Quantitative data analyses were performed on the registered data. Three knee specimens and 15 volunteers were evaluated at 3 T. The elastix motion correction algorithm worked well in correcting motion artifacts associated with relatively long scan times. Much improved curve fitting was achieved for all UTE-Cones biomarkers with greatly reduced root mean square errors. The averaged T1 , T2 *, AdiabT1ρ , MTR and f for knee joint tissues of 15 healthy volunteers were reported. The 3D UTE-Cones quantitative imaging techniques (ie, T1 , T2 *, AdiabT1ρ , MTR and MT modeling) together with elastix motion correction provide robust volumetric measurement of relaxation times, MTR and f of both short and long T2 tissues in the knee joint.

中文翻译：

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带运动校正的膝关节定量三维超短回波时间锥成像。

膝关节退化涉及关节中的所有主要组织。然而，传统的MRI序列只能检测到来自浅层软骨等长T2组织的信号，而来自深部软骨、半月板、韧带、肌腱和骨骼的信号很少。非常需要开发可以检测来自膝关节所有主要组织的信号的新序列。我们旨在开发一种全面的定量三维超短回波时间 (3D UTE) 锥体成像协议，用于对膝关节退化进行真正的“全关节”评估。该协议包括用于 T1 映射的 3D UTE 锥体实际翻转角成像 (3D UTE-Cones-AFI)、用于 T2 * 映射的具有脂肪抑制的多回波 UTE-Cones、用于 AdiabT1ρ 映射的具有绝热 T1ρ (AdiabT1ρ ) 的 UTE-Cones，和 UTE-Cones 磁化转移 (UTE-Cones-MT) 的 MT 比率 (MTR) 和大分子质子分数 (f) 的建模。使用弹性配准技术来补偿扫描期间的运动。对注册数据进行了定量数据分析。三个膝关节标本和 15 名志愿者在 3 T 下进行评估。 elastix 运动校正算法在校正与较长扫描时间相关的运动伪影方面效果很好。所有 UTE-Cones 生物标志物都实现了大大改进的曲线拟合，大大降低了均方根误差。报告了 15 名健康志愿者膝关节组织的平均 T1、T2*、AdiabT1ρ、MTR 和 f。3D UTE-Cones 定量成像技术（即 T1、T2 *、AdiabT1ρ、