School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0SP, UK.
, London, UK.
BMC Musculoskelet Disord. 2021 Oct 30;22(1):916. doi: 10.1186/s12891-021-04755-y.
Quantitative magnetic resonance imaging (MRI) methods such as T1rho and T2 mapping are sensitive to changes in tissue composition, however their use in cruciate ligament assessment has been limited to studies of asymptomatic populations or patients with posterior cruciate ligament tears only. The aim of this preliminary study was to compare T1rho and T2 relaxation times of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) between subjects with mild-to-moderate knee osteoarthritis (OA) and healthy controls.
A single knee of 15 patients with mild-to-moderate knee OA (Kellgren-Lawrence grades 2-3) and of 6 age-matched controls was imaged using a 3.0 T MRI. Three-dimensional (3D) fat-saturated spoiled gradient recalled-echo images were acquired for morphological assessment and T1ρ- and T2-prepared pseudo-steady-state 3D fast spin echo images for compositional assessment of the cruciate ligaments. Manual segmentation of whole ACL and PCL, as well as proximal / middle / distal thirds of both ligaments was carried out by two readers using ITK-SNAP and mean relaxation times were recorded. Variation between thirds of the ligament were assessed using repeated measures ANOVAs and differences in these variations between groups using a Kruskal-Wallis test. Inter- and intra-rater reliability were assessed using intraclass correlation coefficients (ICCs).
In OA knees, both T1rho and T2 values were significantly higher in the distal ACL when compared to the rest of the ligament with the greatest differences in T1rho (e.g. distal mean = 54.5 ms, proximal = 47.0 ms, p < 0.001). The variation of T2 values within the PCL was lower in OA knees (OA: distal vs middle vs proximal mean = 28.5 ms vs 29.1 ms vs 28.7 ms, p = 0.748; Control: distal vs middle vs proximal mean = 26.4 ms vs 32.7 ms vs 33.3 ms, p = 0.009). ICCs were excellent for the majority of variables.
T1rho and T2 mapping of the cruciate ligaments is feasible and reliable. Changes within ligaments associated with OA may not be homogeneous. This study is an important step forward in developing a non-invasive, radiological biomarker to assess the ligaments in diseased human populations in-vivo.
定量磁共振成像（MRI）方法，如 T1rho 和 T2 映射，对组织成分的变化很敏感，但其在十字韧带评估中的应用仅限于无症状人群或仅患有后十字韧带撕裂的患者。本初步研究的目的是比较轻度至中度膝骨关节炎（OA）患者与健康对照者的前十字韧带（ACL）和后十字韧带（PCL）的 T1rho 和 T2 弛豫时间。
对 15 例轻度至中度膝 OA（Kellgren-Lawrence 分级 2-3）患者的单膝和 6 名年龄匹配的对照者进行 3.0T MRI 成像。采集三维（3D）脂肪饱和扰相梯度回波图像进行形态评估，以及 T1ρ和 T2 预备伪稳态 3D 快速自旋回波图像进行十字韧带的成分评估。由两位读者使用 ITK-SNAP 对整个 ACL 和 PCL 以及韧带的近端/中间/远端三分之一进行手动分割，并记录平均弛豫时间。使用重复测量方差分析评估韧带三分之一之间的差异，并使用 Kruskal-Wallis 检验评估组间差异。使用组内相关系数（ICC）评估组内和组间的可靠性。
在 OA 膝关节中，与其余韧带相比，远端 ACL 的 T1rho 和 T2 值均显著升高，T1rho 的差异最大（例如，远端平均值=54.5ms，近端=47.0ms，p<0.001）。OA 膝关节中 PCL 内 T2 值的变化较低（OA：远端与中间与近端平均值=28.5ms 与 29.1ms 与 28.7ms，p=0.748；对照：远端与中间与近端平均值=26.4ms 与 32.7ms 与 33.3ms，p=0.009）。大多数变量的 ICC 均为优秀。
十字韧带的 T1rho 和 T2 制图是可行且可靠的。与 OA 相关的韧带内的变化可能不是均匀的。本研究是朝着开发一种非侵入性、放射学生物标志物以评估体内患病人群韧带的方向迈出的重要一步。
