Comparison of computed tomographic images of normal cranial and upper cervical lymph nodes with corresponding E12 plastinated-embedded sections in the dog

To document normal lymph nodes on computed tomographic images, 102 scans were reviewed of dogs that had computed tomography (CT) of the head and upper cervical region. If lymph nodes were identified, symmetry, density, homogeneity, and size, as well as the relation to the surrounding fat tissue were noted. CT images with distinct asymmetric, enlarged, and obliterated lymph nodes were excluded. To improve the detailed anatomical topography, corresponding E12 plastinated-embedded sections of a dog were used. Compared with muscle tissue, normal lymph nodes were slightly hypodense and had a homogeneous parenchyma. Mandibular and retropharyngeal lymphocentres could be seen consistently and CT proved to be a useful method both to detect their presence and to assess their morphology. It was not possible to identify the parotid lymph node consistently because of the lack of tissue contrast at the lymph node-gland interface.