Imaging the Intestine Tony Pease, DVM, MS Assistant Professor of Radiology North Carolina State University

Reading Thrall Chapters 48-49

Small intestine Small intestine Seen normally with gas or fluid Cannot tell bowel wall thickness without contrast medium present

Ileus The failure of movement Divided into functional and mechanical Problem with motility due to any cause Mechanical Physical obstruction impeding flow

Functional Diffuse SI fluid

Remember, large animals stand! 855921 presumed anterior enteritis in a arab foal

Mechanical Cloth foreign body in stomach/duodenum

Small colon impaction 3 day old foal, 360 colon torsion 859028

Don’t forget foreign bodies Pine cone 127778

Remember!! If you can’t see the foreign body The question to ask Try another view The question to ask Is the small intestine bigger than it should be? Cat < 13 mm diameter Dog < the size of the colon

Rock

Not always opaque!

A Cork

Linear foreign bodies Causes plication Crescent shaped +/- peritonitis

Positioning Horizontal Beam Vertical Beam

Linear foreign body 149097 DSH Linear foreign body

Linear foreign body

The second half of contrast media Evaluate the small intestine Can see flocculation Fimbriation (wispiness)

Flocculation Occurs with mucous or hemorrhage

Fimbriation

Patterns with contrast media Infiltrative bowel disease Linear foreign bodies Obstruction Annular Intraluminal

“Thumbprinting” Regularly spaces divots Inflammation/infiltration Lymphocytic-plasmocytic enteritis Parvovirus Lymphoma Eosinophilic infiltration

Thumbprinting 30 min

Infiltrative disease

Linear foreign body

Chronic partial bowel obstruction Can get quite large and distended Specific syndrome in Saimese Distal ileal adenocarcinoma Generally the mass is palpable

Partial obstruction

Chronic annular mass Lymphoma or adenocarcinoma

Intraluminal object With contrast medium – filling defect Even if radio-opaque on survey

Small intestine Lesion can be seen on radiograph Ultrasound Needs to be large Generally see effect of lesion Ultrasound Can see the lesion better Eccentric vs concentric Loss of wall layering

Small intestine

Can also see foreign bodies

What about equine?

Can use ultrasound also Usually < 5 mm thick If > 5 cm diameter = obstruction

Normal small intestine

Distended small intestine

Remember ultrasound’s benefit

What about the colon? In small animal Colonic neoplasia Polyps Not many things happen to colon Colonic neoplasia Adenoma vs. adenocarcinoma Polyps Stricture

Positive contrast medium Use a foley catheter Inject 7-17 ml per kilogram Multiple views Need an enema first Uses to help differentiate from small intestine

Negative contrast Inject room air into colon Helps define masses Risk of air embolism Do not do if suspect colitis Helps define masses

Colonic ultrasound Gas is a big problem Enema is preferred Generally looking at lymph nodes

Colon neoplasia

Conclusion Thickness of GI If suspect mechanical obstruction Need contrast medium If suspect mechanical obstruction Surgery If you are not sure Take another view Recommend ultrasound

Questions?