A lateral and a VD radiograph will be adequate for assessing the abdomen completely in many canine and feline patients. However, the abdomen contains a valuable inherent contrast medium—gas. Thus, by routinely acquiring left and right lateral radiographs in addition to the VD view, redistribution of bowel gas between the two lateral views can provide valuable additional information that can make the difference between obtaining the diagnosis or not (Fig. 35-1). Dorsoventral radiographs of the abdomen are rarely made and should not form the basis of the orthogonal view to complement the lateral projections. A DV view may have to suffice when a patient cannot be positioned in dorsal recumbency for a VD view, but the abdomen will be more crowded, organ conspicuity will be reduced, and portions of the pelvic limbs are often superimposed on the abdomen (see Fig. 35-9 for an example). A compression radiograph can be used to clarify a suspicious finding that cannot be confirmed because of superimposition.1 The theory is to apply mild compression to displace superimposed organs from the field of view, leaving an unobstructed view of the region of interest. This technique can be applied to assess structures such as the uterine body (lateral view) or the caudal aspect of the retroperitoneal space (VD view). Specialized inflatable compression paddles are available, but a wooden spatula or wooden spoon can also be used. If using a film-screen system, the kVp should be decreased by approximately 15% because the compressed part will be reduced in thickness. Of course, care should be taken not to place compression on organs that are obviously diseased, and the amount of pressure placed should always be gentle (Fig. 35-4). The increased use of ultrasound for abdominal assessment has reduced the need for compression radiographs, but they remain a convenient method to increase the accuracy of radiographic interpretation in some patients where ultrasonography is not possible. One major difference between left and right lateral abdominal radiographs in dogs and cats is the appearance of the stomach. This relates to the difference in the anatomic position of the gastric fundus versus the gastric pylorus.2,3 When looking at a cross-section of the abdomen from the caudal aspect of a dog or cat, the fundus is located dorsally and on the left versus the pylorus, which is located ventrally and on the right (Fig. 35-5
Principles of Radiographic Interpretation of the Abdomen
Positioning—Dog and Cat
Lateral View
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Principles of Radiographic Interpretation of the Abdomen
