Haffner-Luntzer Melanie, Müller-Graf Fabian, Matthys Romano, Abaei Alireza, Jonas René, Gebhard Florian, Rasche Volker, Ignatius Anita
Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm;
Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm; Department of Traumatology, Hand-, Plastic-, and Reconstructive Surgery, University Medical Center Ulm.
J Vis Exp. 2017 Nov 14(129):56679. doi: 10.3791/56679.
Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The amount of the different tissues in the callus provides important information on the fracture healing progress. Available in vivo techniques to longitudinally monitor the callus tissue development in preclinical fracture-healing studies using small animals include digital radiography and µCT imaging. However, both techniques are only able to distinguish between mineralized and non-mineralized tissue. Consequently, it is impossible to discriminate cartilage from fibrous tissue. In contrast, magnetic resonance imaging (MRI) visualizes anatomical structures based on their water content and might therefore be able to noninvasively identify soft tissue and cartilage in the fracture callus. Here, we report the use of an MRI-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice. The experiments demonstrated that the fixator and a custom-made mounting device allow repetitive MRI scans, thus enabling longitudinal analysis of fracture-callus tissue development.
软骨内骨折愈合是一个复杂的过程，涉及骨折痂中纤维组织、软骨组织和骨组织的形成。痂中不同组织的数量为骨折愈合进程提供了重要信息。在临床前骨折愈合研究中，使用小动物纵向监测痂组织发育的现有体内技术包括数字X线摄影和μCT成像。然而，这两种技术都只能区分矿化组织和非矿化组织。因此，无法区分软骨和纤维组织。相比之下，磁共振成像（MRI）基于解剖结构的含水量对其进行可视化，因此可能能够无创识别骨折痂中的软组织和软骨。在此，我们报告了一种用于小鼠股骨的MRI兼容外固定器，以便在小鼠骨再生过程中进行MRI扫描。实验表明，该固定器和定制的安装装置允许重复进行MRI扫描，从而能够对骨折痂组织发育进行纵向分析。
