Diagnosis of a Mesenteric Artery Ultrasound
Disorders of the mesenteric arterial blood supply to the intestines can present either chronically or acutely.
- Chronic presentations from mesenteric arterial atherosclerosis and stenosis present with abdominal pain and bowel dysfunction. Since atherosclerosis is a progressive disease, so are the symptoms.
- Acute presentations from thromboembolism that suddenly occludes the arterial blood supply to the intestinal tract will typically manifest as sudden, severe abdominal pain and cramping, bloody diarrhea, and when necrosis is present, high fever.
Types of Testing That Can Be Preformed.
- Blood Tests: Blood tests provide only non-specific results and can even be normal with intestinal ischemia. Because of the urgency in establishing a diagnosis for mesenteric disease resulting in intestinal ischemia, waiting for the results of blood tests is ill-advised. Once results do come in, however, elevations in serum lactate and serum amylase levels are often present.
- X-rays: Plain abdominal radiography is not very helpful and can be completely normal in 25% of patients with mesenteric ischemia. Positive findings that can be seen include distended loops of bowel, bowel wall thickening, or even free air in the abdomen from a rupture of a portion of necrotic bowel. Any rupture is a surgical emergency.
- Duplex Ultrasound: B (brightness) mode and Doppler ultrasonography can help identify arterial stenosis in chronic disease or occlusion of the superior mesenteric artery in acute situations, and when such conditions are suspected, confirmation is made via CT without contrast and/or rectosigmoidoscopy to rule out bowel ischemia and necrosis.
- CT: CT imaging is preferred to MRI, since it is quicker, less expensive, and readily available in most facilities. Contrast is typically not used because it interferes with visualizing some details, such as bowel wall integrity.
Tests to Exclude Other Conditions
The clinical presentation typical of bowel ischemia and/or necrosis can be similar to other conditions, such as Clostridium difficile colitis, and stool examination is part of the investigation of any serious intestinal conditions. Enzyme immunoassays, cell cultures, anaerobic cultures, and nucleic acid amplification testing are used to rule out this serious infection whose signs and symptoms can mimic bowel ischemia.