Ultrasonography
Ultrasonography has become increasingly important in diagnosing GI disease.17,18 Ultrasonographic studies are noninvasive, accurate for diagnosing linear foreign bodies, and provide information relative
to GI function and disease location.19,20 Abnormal echogenic material within the lumen indicates a foreign body2; however, the appearance of foreign material will vary depending on its physical properties. Linear foreign bodies are linear
structures located eccentrically within the lumen of thickened, plicated bowel.19 The integrity of the intestinal wall can be evaluated based on the presence of fluid or air outside the GI tract. In the
absence of free gas, a combination of ultrasonographic findings such as bright mesenteric fat, peritoneal effusion, fluid-filled
stomach and intestines, wall thickening, reduced motility, and loss of wall layering (the mucosa, submucosa, muscle, and serosa
are usually easily seen with ultrasonography as adjacent layers) may be associated with perforation.21 In this case, the presence of linear echogenic material within the stomach and extending into the small intestine, with
associated plication, was recognized as linear foreign material without evidence of GI perforation.
CONCLUSION
All abdominal radiographic views, including right lateral, left lateral, and ventrodorsal, are important in identifying foreign
material in the gi tract. The main goal of placing patients in these different positions is to use intestinal gas as negative
contrast to localize the foreign body. It is important to distinguish the normal location of air and fluid in every view.
When an isolated organ evaluation is needed, compression radiography is an inexpensive and easy technique. Positive contrast
studies provide useful information regarding the location and the degree of the obstruction and should be used in small-animal
practice. Ultrasonographic evaluation provides information about the shape and position of the stomach or bowel and the presence
of intraluminal structures, as well as the ability to measure bowel wall thickness and evaluate intestinal wall layers. Typical
intestinal shapes associated with linear foreign bodies, intussusceptions, and other kinds of foreign materials have been
described elsewhere. 1
Using the most accurate, least invasive diagnostic imaging technique is imperative for optimizing care in patients with linear
foreign bodies. Additional studies are indicated when the diagnosis is uncertain with survey radiography. It will not be necessary
to perform all of these techniques in every patient.
Luis M. Gonzalez, DVM, MS*
David S. Biller, DVM, DACVR
Laura J. Armbrust, DVM, DACVR
Department of Clinical Sciences
College of Veterinary Medicine
Kansas State University
Manhattan, KS 66506
*Dr. Gonzalez's current address is Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary
Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061.
REFERENCES
1. Bebchuk TN. Feline gastrointestinal foreign bodies. Vet Clin North Am Small Anim Pract 2002;32:861-880.
2. Burk RL, Ackerman N. The abdomen. In: Small animal radiology and ultrasonography: a diagnostic atlas and text. 2nd ed. Philadelphia, Pa: WB Saunders Co, 1996;215-426.
3. Bowlus RA, Biller DS, Ambrust LJ, et al. Clinical utility of pneumogastrography in dogs. J Am Anim Hosp Assoc 2005;41:171-178.
4. Riedesel EA. The small bowel. In: Thrall DE, ed. Textbook of veterinary diagnostic radiology. Philadelphia, Pa: WB Saunders Co, 2002;639-660.
5. Ljunggren G. The radiological diagnosis of some acute abdominal disorders in the dog. J Am Vet Radiol Soc 1964;5:5-14.
6. Root CR, Lord PF. Linear radiolucent gastrointestinal foreign bodies in cats and dogs: their radiographic appearance. J Am Vet Radiol Soc 1971;12:45-53.
7. Farrow CS. Radiographic characterization of gastric foreign material in a dog. Mod Vet Pract 1986;67:716-718.
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