Diagnostic imaging for linear foreign bodies in cats - Veterinary Medicine
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Diagnostic imaging for linear foreign bodies in cats
These clinicians focus on their diagnostic evaluation of a cat with vomiting and abdominal pain due to a linear foreign body. Find out which imaging techniques will best help you identify these common gastrointestinal foreign bodies in your patients.


On survey radiographs, intestinal linear foreign bodies can cause abnormal shape, contour, and luminal content pattern.2,4 They can also produce an accordion-like pleating, shortening, or gathering of the small intestine because of peristalsis.1-6 Because the antimesenteric border of the intestine is longer than the mesenteric border, gas commonly becomes trapped in pockets formed by the pleats, resulting in an abnormal pattern of unconnected round, tapered, and short tubular gas shapes. Repositioning the patient in the opposite lateral recumbency causes redistribution of intestinal gas, which serves as negative contrast media for this second lateral view. This negative contrast can be helpful in localizing the foreign body.7-9 That is particularly true in the case of pyloric foreign bodies because in right lateral recumbency, gas accumulates in the fundus, but in left lateral recumbency, gas is present in the pyloric region.9,10 On the right and left lateral views, evaluating gas within the small or large intestine may help differentiate various segments of the intestine as well as elucidate abnormalities.9 Additional abnormalities such as free air, loss of serosal detail (denoting abdominal effusion), and soft tissue masses are easily observed on survey films.2,4

Compression radiography

Compression radiography is a fast and easy way to isolate and evaluate abdominal structures, including the small intestine.11 This technique's advantage is the isolation of organs of interest to provide evaluation without summation and superimposition from other organs.11,12

The technique is simple and has been described elsewhere.11 Briefly, the area of the target organ of interest is compressed with a wooden or plastic spoon, paddles, or any rigid and radiolucent material that has a surface 1.5 times the size of the area of interest. Minimize patient discomfort by compressing the area with your hand before placing the radiolucent device over it, and then slip your hand out.11 Compression can also be used with a contrast study.

In this case, the compression technique elucidated an area of small-bowel plication. To prevent potential complications such as bowel rupture and peritonitis, carefully consider that friable intestine may be present when you perform compression in patients with severe abdominal pain. We have used abdominal compression radiography in several cases with no complications; however, we recommend compressing the abdomen gently.

Positive contrast upper GI radiography

Another technique that can be used to diagnose linear foreign bodies is a positive contrast upper GI study, but it was unnecessary in this case. These studies can be used to evaluate small intestinal foreign bodies, strictures, mucosal disease, and abnormal transit times.1,4,10

A GI study can be done with either micropulverized barium sulfate solution or water-soluble iodinated products. Barium sulfate suspensions are radiopaque, provide excellent mucosal detail, and are inexpensive.13,14 If leakage into the peritoneal cavity occurs, barium combined with enteric contents may cause granulomas or adhesions.4 By comparison, iodinated ionic solutions have a rapid transit time, are nonirritating to serosal surfaces, are rapidly resorbed following extraluminal leakage, and can be followed quickly by endoscopic evaluation if indicated.15 However, iodinated ionic solutions are hypertonic, which cause an influx of fluid into the GI tract, making them contraindicated in debilitated and dehydrated patients.4,15 Thus, although vomiting has been reported within 15 to 30 minutes after administration of undiluted iohexol (a nonionic iodinated positive contrast agent) in experimental studies in cats, we recommend nonionic contrast media.16

Contrast studies are time-consuming. In some cases, further attempts to define the specific site and type of obstruction with contrast media may only delay and complicate surgery or further compromise the patient.4


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