Which vessel is described as fasting when evaluating mesenteric arteries?

• A. Renal Artery
• B. Common Hepatic Artery
• C. Superior Mesenteric Artery
• D. Inferior Mesenteric Artery

Answer: (C)

The superior mesenteric artery is the one described as fasting in this context. When evaluating mesenteric arteries with Doppler, imaging is typically done in a fasting state because the gut’s blood flow rises after a meal (postprandial hyperemia). This meal-induced increase mainly affects the SMA, raising flow and velocity and potentially masking or mimicking stenosis. Scanning while fasting provides a lower, baseline flow, making abnormal velocities due to true narrowing more reliable to identify. The other vessels listed are not the focus of the fasting evaluation for mesenteric ischemia.