Imaging of the brain and surrounding tissue is necessary to eliminate other intracranial causes of seizure. Magnetic resonance imaging (MRI) and computed tomography (CT) can both be used to identify (or rule out) structural brain disease. However, a normal CT scan does not exclude the possibility of cerebral pathology. Inflammatory or infectious CNS diseases are rarely detectable with MRI or CT and if these are suspected a CSF sample may be required for diagnosis. MRI is most likely to be useful in animals in which onset of seizures occurs after the age of 6 years, or those in which seizures are refractory to standard treatments. In addition to identifying an underlying cause of seizures, MRI or CT is required as an aid to treatment planning (radiotherapy or surgery) for intracranial masses. Skull radiography is rarely of any value.

Screening thoracic and abdominal radiographs are used to help rule out systemic conditions causing seizures. Ultrasonography may be useful to further evaluate suspected cardiovascular or metabolic disease, eg portosystemic shunts.

Magnetic resonance imaging of the brain

Although it is unlikely that the veterinarian in practice will have to undertake MRI or to interpret the scans, it is useful to have an understanding of what can be seen and what diagnoses can be made using this modality. Further information on the subject can be found here.