Page 334 - Feline diagnostic imaging

342 21 Normal Gastrointestinal Anatomy

(a)

(b)

Figure 21.9 (a) Lateral projection showing pneumocolography in a cat with a history of bloody diarrhea and chronic intermittent
weight loss. Fifteen milliliters of air was instilled into the colon using a catheter placed in the rectum. The air allowed visualization of
colonic wall thickening with narrowing of the lumen (arrow). Source: Image courtesy of Dr Adrien-Maxence Hespel. (b) Compare the
image in (a) with this image of an air-filled normal colon.

radiograph before administering more barium. The colon barium administration has occurred but even intestinal
should be only mildly distended. A double‐contrast barium contents alone in the peritoneal cavity presents an emer-
enema can be done by lowering the enema bag to allow gency situation. In either case, the patient should be imme-
removal of most of the barium prior to instilling air into diately taken to surgery.
the colon. In lieu of a complete study, some barium can be
instilled into the colon through a rubber catheter to outline
portions of the colon (Figure 21.10). 21.3 Ultrasonography
The normal colon should have smooth margins. In a of the Gastrointestinal Tract
double‐contrast study, barium should coat the mucosa
while air in the lumen provides contrast. The most serious 21.3.1 Esophagus
complication is tearing of the colon or rectum which can
occur particularly with severe ulceration. If perforation of The cervical esophagus is difficult to identify but appears
the colon or rectum is suspected, the procedure should as a circular structure in transverse section. The star‐
immediately be stopped. The prognosis is worsened if shaped center is hyperechoic due to the presence of