Computed tomography of the tarsal joint in clinically normal dogs

To use computed tomography to provide a detailed description of tarsal joint structures in clinically normal dogs. 6 clinically normal adult mixed-breed dogs weighing 25 to 35 kg and one 12-month-old Bullmastiff weighing 65 kg. To perform computed tomography (CT) of both tarsal regions, dogs were anesthetized and placed in ventral recumbency. One- and 2-mm contiguous slices were obtained, using a third generation CT scanner Individual images were reviewed, using bone (window width = 3,500 Hounsfield units; window level = 500 Hounsfield units) and soft-tissue (window width = 400 Hounsfield units; window level = 66 Hounsfield units) settings. After euthanasia, the hind limbs from the Bullmastiff were removed and frozen at -18 C. Tarsal joints were sectioned into approximately 1-mm-thick slab sections, using a cryomicrotome. Anatomic sections were photographed and compared with the corresponding CT images. Computed tomographic reconstructions of the tarsocrural joint were created in sagittal and dorsal planes. Structures on the CT images were matched with structures in the corresponding anatomic sections. The entire tarsocrural joint surface could be evaluated on the reconstructed images in the sagittal and dorsal planes. CT images provide full anatomic detail of the bony structures of the tarsal joint in dogs. Tendons and large blood vessels can also be evaluated. These results could be used as a basis for evaluation of CT images of the hind limbs of dogs with tarsal joint injuries.