Imaging techniques for the pancreas (Proceedings)

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Imaging techniques for the pancreas (Proceedings)

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Apr 01, 2008

Introduction

Pancreatitis is a common consideration in dogs and in an increasing number of cats presented for vomiting, anorexia, lethargy, or abdominal pain. The disease however, is difficult to diagnose definitively, especially in cats. Clinicopathologic data, including amylase and lipase values are used routinely when canine pancreatitis is suspected. However, they may be normal, or elevated from other disease processes. They are not useful in cats. Newer tests, including canine and feline PLI are being used with increasing frequency, and are now commercially available. They appear to be fairly sensitive for pancreatits, but results are not available for several days. Imaging techniques have become an essential part of the workup in patients suspected of having pancreatitis.

Radiology of the pancreas

The normal canine pancreas is not seen on abdominal radiographs. However, in cats, the left pancreatic limb can often be seen as a thin linear soft tissue opacity extending to the left, between the gastric fundus, cranial pole of the left kidney, and spleen.


Lateral abdominal radiograph of a dog with pancreatitis. There is a mass effect in the cranial abdomen, caudal to the stomach, as well as ventral displacement of the gas-filled descending duodenum.
Both acute and chronic pancreatitis, as well as pancreatic neoplasia can result in changes visible on survey abdominal radiographs. Potential radiographic signs include:
1. Loss of abdominal detail, primarily in the right cranial abdomen, due to focal peritonitis
2. Mass effect in the right cranial abdomen
3. Displacement of the pylorus cranially, or to the left
4. Ventral or right sided displacement of the descending duodenum
5. Caudal displacement of the transverse colon
6. Bowel loops adjacent to the pancreas (usually duodenum) may be gas-filled (ileus), or corrugated/spastic in appearance

Radiographs are frequently normal in dogs and cats with pancreatitis. In a previous study, only 24% (10/70 cases) of dogs with acute pancreatitis had radiographic changes consistent with this disease. Computed tomography is a sensitive means of making a diagnosis of pancreatitis or pancreatic neoplasia in people, but has limited availability, is expensive, and requires general anesthesia in veterinary medicine. Ultrasound, therefore, has become the imaging modality of choice in the diagnosis of pancreatic disease. Ultrasound examination of the pancreas can be difficult, however. The canine pancreas, unlike the liver or spleen, is often not seen as a discrete organ, and therefore the pancreatic region and its anatomic landmarks must be examined. The pancreas is surrounded by gas filled structures, including the duodenum, stomach, and colon, which may obscure visualization. Finally, abdominal pain in patients with pancreatitis may prevent the firm pressure on the transducer needed to visualize the pancreatic area.