Department of Radiology, University of California-San Diego, 9427 Health Sciences Drive, La Jolla, CA, USA.
Department of Radiology, VA San Diego Healthcare System, San Diego, CA, USA.
Jpn J Radiol. 2023 Nov;41(11):1308-1315. doi: 10.1007/s11604-023-01453-8. Epub 2023 May 29.
For biochemical evaluation of soft tissues of the knee, T1rho magnetic resonance imaging (MRI) has been proposed. Purpose of this study was to compare three T1rho sequences based on fast advanced spin echo (FASE), ultrashort echo time (UTE), and magnetization-prepared angle-modulated partitioned k-space spoiled gradient echo snapshots (MAPSS) acquisitions for the knee evaluation.
We developed two T1rho sequences using 3D FASE or 3D radial UTE acquisitions. 3D MAPSS T1rho was provided by the manufacturer. Agarose phantoms with varying concentrations were imaged. Additionally, bilateral knees of asymptomatic subjects were imaged sagittally. T1rho values of the phantoms and 4 regions of interest (ROI) of the knees (i.e., anterior and posterior meniscus, femoral and tibial cartilage) were determined.
In phantoms, all T1rho values monotonically decreased with increasing agarose concentration. 3D MAPSS T1rho values of 51, 34, and 38 ms were found for 2, 3, and 4% agarose, respectively, similar to published values on another platform. In the knee, the raw images were detailed with good contrast. Cartilage and meniscus T1rho values varied with the pulse sequence, being the lowest in the 3D UTE T1rho sequence. Comparing different ROIs, menisci generally had lower T1rho values compared to cartilage, as expected in healthy knees.
We have successfully developed and implemented the new T1rho sequences and validated them using agarose phantoms and volunteer knees. All sequences were optimized to be clinically feasible (~ 5 min or less) and yielded satisfactory image quality and T1rho values consistent with the literature.
为了对膝关节的软组织进行生化评估，已经提出了 T1rho 磁共振成像（MRI）。本研究的目的是比较三种基于快速先进自旋回波（FASE）、超短回波时间（UTE）和磁化准备角调制分区 K 空间扰动脉冲梯度回波快照（MAPSS）采集的 T1rho 序列，用于膝关节评估。
我们使用 3D FASE 或 3D 径向 UTE 采集开发了两种 T1rho 序列。3D MAPSS T1rho 由制造商提供。对具有不同浓度的琼脂糖幻影进行成像。此外，对无症状受试者的双侧膝关节进行矢状位成像。确定幻影的 T1rho 值和膝关节的 4 个感兴趣区域（ROI）（即前、后半月板、股骨和胫骨软骨）的 T1rho 值。
在幻影中，所有 T1rho 值均随琼脂糖浓度的增加而单调下降。对于 2%、3%和 4%的琼脂糖，分别发现 3D MAPSS T1rho 值为 51、34 和 38ms，与另一平台上发表的值相似。在膝关节中，原始图像具有良好的对比度，细节丰富。软骨和半月板的 T1rho 值随脉冲序列而变化，在 3D UTE T1rho 序列中最低。比较不同的 ROI，半月板的 T1rho 值通常比软骨低，这在健康的膝关节中是可以预期的。
我们已经成功开发并实施了新的 T1rho 序列，并使用琼脂糖幻影和志愿者膝关节对其进行了验证。所有序列均经过优化，使其在临床上可行（约 5 分钟或更短），并产生了令人满意的图像质量和与文献一致的 T1rho 值。
