Usefulness of US in the detection of gastrointestinal foreign bodies in pets.

Background: Roentgen signs that accompany mechanical obstruction of the small intestine are usually non specific as there are numerous other causes of obstruction of the gastrointestinal (g-i) tract including neoplasia, intussusception, etc.. Objective: To evaluate the diagnostic sensitivity and specificity of US in the detection of g-i foreign bodies. Patients and Methods: 30 consecutive patients (19 dogs, 11 cats) suspected of the presence of g-i FBs underwent a complete US examination of the abdomen. 5-7.5 MHz microconvex or linear array 7.5-10 MHz transducers were used. FBs were recognized by their shape, strong distal acoustic shadowing and variable degrees of surface reflection. The presence of gastric or intestinal distension was assessed subjectively. The g-i contents, segmental increased or absence of peristalsis, lymphoadenopathy, increased echogenicity of the mesentery, and whether an effusion was present was also recorded. Results: A g-I FB was detected ultrasonographically in 18 animals (14 dogs, 4 cats): 3 FBs were in the stomach; 15 FBs were detected in the small bowel (3 out of those 15 were linear FBs and 11 were radiotransparent FBs). FBs were confirmed endoscopically or surgically in 16 animals. In one dog the intestinal FB was located in correspondence of an intestinal mass (carcinoma). Among the remaining 12 animals (5 dogs, 7 cats) no g-i FBs were detected and different diagnosis (4 intestinal neoplasia) were assessed. Sensitivity of US was 100% and specificity 85.7%. Conclusions: These findings suggest that US could be an appropriate choice to make the diagnosis of g-i FBs. Its use, especially in human paediatric medicine, could be considered. The additional information obtained sonographically are also useful in directing the course of treatment also in animals in which no g-i FBs were detected.