Quirbach Sebastian, Trattnig Siegfried, Marlovits Stefan, Zimmermann Valentin, Domayer Stephan, Dorotka Ronald, Mamisch Tallal C, Bohndorf Klaus, Welsch Goetz H
MR Center--High-Field MR, Department of Radiology, Medical University of Vienna, Vienna General Hospital, Waehringer Guertel 18-20, 1090, Vienna, Austria.
Skeletal Radiol. 2009 Aug;38(8):751-60. doi: 10.1007/s00256-009-0682-1. Epub 2009 Mar 19.
The aim of this study was to use morphological as well as biochemical (T2 and T2* relaxation times and diffusion-weighted imaging (DWI)) magnetic resonance imaging (MRI) for the evaluation of healthy cartilage and cartilage repair tissue after matrix-associated autologous chondrocyte transplantation (MACT) of the ankle joint.
Ten healthy volunteers (mean age, 32.4 years) and 12 patients who underwent MACT of the ankle joint (mean age, 32.8 years) were included. In order to evaluate possible maturation effects, patients were separated into short-term (6-13 months) and long-term (20-54 months) follow-up cohorts. MRI was performed on a 3.0-T magnetic resonance (MR) scanner using a new dedicated eight-channel foot-and-ankle coil. Using high-resolution morphological MRI, the magnetic resonance observation of cartilage repair tissue (MOCART) score was assessed. For biochemical MRI, T2 mapping, T2* mapping, and DWI were obtained. Region-of-interest analysis was performed within native cartilage of the volunteers and control cartilage as well as cartilage repair tissue in the patients subsequent to MACT.
The overall MOCART score in patients after MACT was 73.8. T2 relaxation times (approximately 50 ms), T2* relaxation times (approximately 16 ms), and the diffusion constant for DWI (approximately 1.3) were comparable for the healthy volunteers and the control cartilage in the patients after MACT. The cartilage repair tissue showed no significant difference in T2 and T2* relaxation times (p > or = 0.05) compared to the control cartilage; however, a significantly higher diffusivity (approximately 1.5; p < 0.05) was noted in the cartilage repair tissue.
The obtained results suggest that besides morphological MRI and biochemical MR techniques, such as T2 and T2* mapping, DWI may also deliver additional information about the ultrastructure of cartilage and cartilage repair tissue in the ankle joint using high-field MRI, a dedicated multichannel coil, and sophisticated sequences.
本研究旨在运用形态学以及生化（T2和T2*弛豫时间以及扩散加权成像（DWI））磁共振成像（MRI）来评估踝关节基质相关自体软骨细胞移植（MACT）后健康软骨及软骨修复组织。
纳入10名健康志愿者（平均年龄32.4岁）和12名接受踝关节MACT的患者（平均年龄32.8岁）。为评估可能的成熟效应，将患者分为短期（6 - 13个月）和长期（20 - 54个月）随访队列。使用新型专用八通道足踝线圈在3.0 - T磁共振（MR）扫描仪上进行MRI检查。采用高分辨率形态学MRI评估软骨修复组织的磁共振观察（MOCART）评分。进行生化MRI检查时，获取T2图谱、T2*图谱和DWI。在志愿者的天然软骨、对照软骨以及MACT后患者的软骨修复组织内进行感兴趣区分析。
MACT后患者的总体MOCART评分为73.8。健康志愿者和MACT后患者的对照软骨的T2弛豫时间（约50毫秒）、T2弛豫时间（约16毫秒）以及DWI的扩散常数（约1.3）具有可比性。与对照软骨相比，软骨修复组织的T2和T2弛豫时间无显著差异（p≥0.05）；然而，软骨修复组织的扩散率显著更高（约1.5；p＜0.05）。
所得结果表明，除形态学MRI和生化MR技术（如T2和T2*图谱）外，DWI使用高场MRI、专用多通道线圈和复杂序列，也可能提供有关踝关节软骨及软骨修复组织超微结构的额外信息。
