Neuroradiology (Proceedings)

General Comments

• Disease processes are categorized into Congenital, Degenerative, Developmental, Inflammatory, Metabolic, Neoplastic, Traumatic and Miscellaneous processes.

• Young animals are usually affected by Congenital, Developmental, Inflammatory, Metabolic and Traumatic processes.

• Older animals are usually affected by Degenerative, Inflammatory, Metabolic and Neoplastic processes.

• Neoplasia may be seen in the young and trauma may be seen in the old; thus age is not an exclusive predicting factor.

Things I Have Learned

• The survey radiographic study still has a "place" in neuro-imaging-it is the most cost effective method to obtain an overview of the osseous components of this organ system

• Poor quality radiographs- motion artifact, artifacts in general, poor positioning, poor techniques, too few views all distract from your ability to see even large lesions

• You should be able to do a CSF tap via the cerebello-medullary cistern

• When you do a CSF tap use a 22 gauge 1.5 or 2.5 inch needle—if the animal is so big you think you need a 3.5 inch needle-consider referring the pet to a specialist.

• You can not define most soft tissue lesions in the CNS with survey radiographic study-you should refer these patients for MRI or CT imaging

• CT imaging alone or in conjunction with myelography can define some lesions that are not easily seen with MRI or conventional radiology-bone lesions especially.

• A conventional radiographic/myelogram study has mostly been replaced with MRI or CT imaging.

When evaluating the central nervous system radiographically, it is advantageous to: 1)center the beam on the area of interest, 2) use high detail film/screen technology —100-200 speed system if the pet is sedated or anesthetized-or the appropriate digital algorithm 3) use table top technique unless the part is greater than 10 cm in thickness—then use a grid/bucky-some digital systems do not use a grid, 4) remove patient motion artifact, 5) use as many radiographic projections as needed to define the structures/lesions in the area of interest, 6) remove superimposition of unnecessary structures as much as possible, and 7) obtain sequential radiographic studies as clinically indicated to monitor the biological behavior of the lesion/lesions.

Things to remember: 1) many CNS lesions are not defined radiographically when the animal initially presents—the tissues have not been altered sufficiently to be detected radiographically, 2) soft tissues should always be evaluated 3) is there systemic disease such as portosystemic shunt, hepatic failure, renal failure, myasthenia gravis, Addison's disease, auto-immune disease, cardiovascular disease?

Radiographs I Receive with Requested Interpretation Usually Involve:

• Congenital malformations

• Degenerative processes

• Inflammatory processes

• Trauma

• Neoplasia.

My presentation will review the above conditions. The audience will be asked to participate in the presentation so that it will be a discussion rather than a monolog.