DISCUSSION
This case is an excellent example of the importance of evaluating the entire radiographic image. In this case, the cause of
the gagging and presumed vomiting was found not in the abdomen, where the study was focused, but in the thorax on the edges
of the radiographic views.
Other examples of significant findings that are located in an area different from the usual focus of radiographs include pulmonary
metastatic nodules on the edge of an abdominal study and a lytic lesion on a proximal humerus seen on a thoracic study.
Figure 2A. The same radiographs as in Figures 1A & 1B with the contrast and brightness adjusted to make the caudal esophagus
more apparent.
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Developing a systematic method for reading radiographs can help veterinarians avoid missing a lesion. This process is much
like the systematic approach to the physical examination. My method of reading abdominal radiographs is to first evaluate
nonabdominal structures such as the thorax, ribs, spine, pelvis, hindlimbs (if included), and peripheral soft tissues. Then
I evaluate the overall abdominal contrast followed by an examination of specific structures. I move in a cranial-to-caudal
direction—diaphragm, liver, gastrointestinal tract, spleen, kidneys and retroperitoneal area, urinary bladder, and sublumbar
region. The particular method you use is unimportant, as long as a methodology is in place and used consistently. Some people
like to read radiographs right to left, cranial to caudal, top of the film to the bottom, or periphery to center by organ
or organ system.
Figure 2B. The same radiographs as in Figures 1A & 1B with the contrast and brightness adjusted to make the caudal esophagus
more apparent.
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When evaluating radiographic films of the abdomen, a bright light source (hot light) should be used to evaluate any anatomic
areas that are overexposed. Overexposure of thoracic structures routinely occurs with abdominal radiographic technique.
If the images are made by using a digital radiography system, it also is important to adjust the brightness and contrast as
needed, so all parts of the image can be fully evaluated. One of the advantages of using digital radiography is the ability
to adjust contrast and brightness during image interpretation (Figures 2A & 2B).
Editors' note: The American Association of Veterinary Radiologists offers interactive radiology rounds online every other week. To learn
more, visit
http://aavr.org/.
Julie Ekedahl, VMD, DACVR, Veterinary Imaging Specialists of Idaho, Boise, ID 83702, provided this case report.
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