Plain radiographs of the skull and vertebral column are useful to detect fractures, subluxation, infection, or neoplasia of osseous structures. In most infections or neoplastic processes of the brain and spinal cord, plain radiographs are normal. Myelography is used to detect compressive or expansive spinal cord lesions, including herniated or protruded intervertebral discs and spinal cord tumors. CT and MRI scans are useful to evaluate lesions of the brain and spinal cord in small animals. CT scans are helpful to detect changes in bone, acute hemorrhage, and CNS neoplasia. MRI scans are the best to demonstrate soft-tissue changes, eg, neoplasia, abscesses, inflammation, and hemorrhage. MRI is the gold standard for evaluation of lumbosacral disease in small animals. Magnetic resonance angiography can be used to evaluate vascular changes in the CNS.