Multi-parametric visualization of knee joint ultra-structure: Validation of biochemical magnetic resonance imaging - from bench to bedside

用于治疗软骨缺损、半月板病变或前交叉韧带（ACL）撕裂的复杂手术技术需要高质量的随访。除了常规的形态磁共振成像（MRI），成分（生化）MRI是一种新的方法，更全面的分析关节组织。然而，大多数生物化学MR技术尚未通过组织形态学分析得到充分验证，这限制了其在临床前或临床研究中的适用性。虽然通过dGEMRIC或T2弛豫映射的软骨可视化是当前验证研究的主题，但是使用更新的技术，例如23 Na（钠）成像、T2* 映射、T2d映射、超短回波时间（UTE）成像、磁化传递对比（MTC）、弥散加权成像（DWI）或T1 rho，对修复或退行性软骨的分析迄今尚未得到令人满意的验证。此外，这些MR方法的实施还没有得到充分的证明与组织学方法调查半月板或ACL。本补助金的目标是验证这些新的MR技术与组织形态学和超高场（7T）MR显微镜，使用两个建立的动物模型，并实施临床MR随访协议的结果。在20只绵羊的膝关节中，将健康的关节软骨与由关节切除术诱导的退化的关节软骨，或与由微骨折技术（MFX）或基质相关的自体软骨细胞移植（MACT）诱导的两种不同类型的软骨修复组织进行比较。此外，上述生化MR方法将用于评估相关关节结构，包括手术后不同时间点的多参数方法中的膝关节和前交叉韧带。

Sophisticated surgical techniques for the treatment of cartilage defects, meniscus pathologies, or anterior cruciate ligament (ACL) tears, require high quality follow-up. In addition to conventional morphological magnetic resonance imaging (MRI), compositional (biochemical) MRI is a novel approach for a more comprehensive analysis of joint tissues. However, most biochemical MR techniques have not been sufficiently validated by histomorphological analysis as yet, which limits their applicability in pre-clinical or clinical studies. While visualisation of cartilage by dGEMRIC or T2 relaxation mapping are the subject of current validation studies, the analysis of repaired or degenerative cartilage using newer techniques, such as 23Na(sodium) imaging, T2* mapping, T2d mapping, ultra-short echo-time (UTE) imaging, magnetization transfer contrast (MTC), diffusionweighted imaging (DWI), or T1rho, has, to date, not been satisfactorily validated. Furthermore the implementation of these MR methodologies has not been proven adequately with histological methods for investigating the meniscus or the ACL.The goal of the present grant is to validate these novel MR techniques with histomorphology and ultra high-field (7T) MR microscopy, using two established animal models, and to implement the findings into clinical MR follow-up protocols. In the knee joints of 20 sheep, healthy articular cartilage will be compared with either degenerated articular cartilage induced by meniscectomy, or with two different types of cartilage repair tissues induced by the microfracture technique (MFX), or matrix-associated autologous chondrocyte transplantation (MACT). In addition, the above-mentioned biochemical MR methodologies will be used to assess the associated joint structures, including the menisci and anterior cruciate ligament in a multi-parametric approach at different time points after surgery.