Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

338 Small Animal Radiolo g y and Ultrasono graphy
obstruction will not be evident on the noncontrast radiograph. If there are noncontrast
radiographic findings strongly indicative of intestinal obstruction, a GI series may not be
indicated. In these patients, the ineffective peristalsis that produced the ileus will prevent
the contrast from reaching the point of obstruction. This is more often the case in complete
rather than in incomplete obstruction.
Gastrointestinal Series. The GI series may be helpful in defining and delineating lesions
of the small intestine. Although some radiographic changes may be associated more often
with tumor or infection, all may be observed in either condition. A GI series rarely results
in a specific diagnosis and most often confirms the presence of a lesion within the intestines,
and a biopsy must be performed in order to establish a specific diagnosis. The GI
series can be normal despite the presence of disease. As with the stomach, the paramount
criterion of a positive finding is its repeatability. The small intestine normally should
appear as a smooth tube on the GI series. The contrast should pass through the intestines
in a column, with some areas of constriction associated with peristalsis. A brush border at
the interface between the intestinal mucosa and the luminal barium is normal.
Mucosal Patterns. There are a large number of normal mucosal patterns ranging from a
thin streak of barium, or “string sign,” to a roughly cobbled pattern. 107 The only clearly
abnormal mucosal pattern on the GI series is flocculation of the barium. This is a granular
appearance of the contrast medium (Fig. 3-108). It may be caused by poorly mixed barium
suspensions, prolonged passage times, instillation of the barium into large volumes of gastric
fluid, disease causing the presence of excess mucus or hemorrhage in the intestines, or, perhaps,
a change in the intestinal pH. 12 When flocculation is present, infiltrative bowel diseases
or malabsorption syndromes should be considered, such as lymphangiectasia, chronic enteritis,
plasmacytic/lymphocytic enteritis, eosinophilic enteritis, or lymphoma.
Fig. 3-108 A 1-year-old male German Shepherd dog with chronic
diarrhea. The ventrodorsal view revealed a granular, nonhomogeneous
appearance to the barium (flocculation) within the small
intestine. This is most consistent with a malabsorption syndrome.
Differential diagnoses include lymphangiectasia, eosinophilic gastroenteritis,
lymphoma of the small intestine, and chronic enteritis.
Diagnosis: Lymphangiectasia.