What are the differential diagnostic considerations in a patient with suspected AMI, and how do plain abdominal radiographs help elucidate the disorder?
- Flat and upright abdominal plain films should be obtained first in a patient complaining of abdominal pain unless a diagnosis of ischemia is clear.Â
The below table depicts differential diagnoses and associated findings on x-ray.
Radiographic Clues to Diagnosis
| Disorder | Finding on Plain Abdominal Radiographs |
|---|---|
| Small bowel obstruction | Dilated loops of bowel with or without air-fluid levels Stair-step overlapping of loops of small bowel Termination of luminal small bowel air at transition point of obstruction |
| Pancreatitis | Sentinel loop of duodenum or colon cut-off sign |
| Volvulus | Characteristic jejunal, sigmoid, or cecal dilation (sigmoid volvulus—coffee bean sign) |
| Intraabdominal sepsis (appendicitis, diverticulitis) | Air in the hepatic or portal venous system (portal venous gas) |
| Perforation | Free air under the diaphragm Air dissecting between bowel loops or seen retroperitoneally |
| Bowel ischemia | Bowel wall thickening, loop separation, thumbprinting |
| Pneumatosis intestinalis and portal venous gas | Late signs and ominous for impending or frank infarction |
| Emphysematous cholecystitis | Air within the gallbladder wall, air-fluid level in the gallbladder (also caused by gas-forming organisms) |
- Numerous imaging modalities can be employed to further elucidate a diagnosis of mesenteric ischemia, including abdominal computed tomography (CT) with contrast, Doppler of mesenteric vessels, and mesenteric angiography. Laparoscopy and enteroscopy may also be indicated in the appropriate clinical setting.Â
- In patients with bowel infarction, plain films and abdominal CT show nonspecific abnormalities in a minority of cases. Angiography is more effective than CT in identifying mesenteric arterial occlusion or NOMI. If venous occlusive disease is suspected, a dynamic abdominal CT with contrast can be a helpful diagnostic tool.Â
- Of note, barium for small bowel study should be avoided if a contrast CT or angiogram is being considered as barium interferes with the completion and diagnostic interpretation of the aforementioned studies.
