Case-based Comparative Imaging (Radiography, Scintigraphy, MRI) of the Navicular Region

As in other locations imaging is only one step in the diagnostic work up, but often radiography serves as a first step after clinical examination and localisation of the lameness to the distal limb. Good quality of radiographs is mandatory for the evaluation of the navicular bone. Preparation of the foot with removal of hoof shoes and trimming of the foot prevent artefacts and superimposition with dirt or loose horn. Nowadays, digital radiography has replaced conventional films in a lot of places. On the one hand it facilitates developing process and gives the possibility to change image contrast and image brightness to adapt the same image for soft tissues and bone. On the other hand spatial resolution is lower. We use an indirect digital system with screens from mammography with a high resolution. A standard radiographic examination of the navicular bone includes three projections: a true latero-medial, a dorsoproximal- palmarodistal oblique (according to Oxspring) and a proximopalmar- distopalmar tangential view. The lateromedial view delivers a good survey. Even if the main interest might be the navicular bone, hoof conformation, adjacent bones and articulations with the surrounding soft tissues have to be evaluated. The x- ray beam is aligned parallel with the heels in order to achieve an orthogonal projection of the navicular bone. […]