Nonneoplastic disorders of the brain.

Computed tomography (CT) and magnetic resonance imaging (MRI) are helpful in the diagnosis of many nonneoplastic brain disorders in the dog and cat. The ability of CT and MRI to depict normal and abnormal anatomy facilitates the identification of developmental anomalies, including hydrocephalus, Chiari malformations, arachnoid cysts, and cerebellar hypoplasia. These imaging modalities also allow the detection of hemorrhage and infarction and are therefore useful in the evaluation of spontaneous cerebrovascular disorders and head trauma. Finally, many inflammatory diseases, such as encephalitis, brain abscess, and parasite migration, cause abnormalities detectable by CT and MRI. Although more research on the imaging features of specific nonneoplastic brain disorders is needed, current information indicates that CT and MRI are useful in the management of these disorders.