The superior mesenteric artery (SMA) is a large branch of the abdominal aorta that supplies blood to most of the small intestine, the cecum, ascending colon, and part of the transverse colon. On ultrasound, the SMA is identified originating from the anterior aorta, just below the celiac trunk, and it serves as an important anatomic landmark — the pancreas lies between the SMA and the aorta. Doppler evaluation of the SMA assesses for stenosis (which can cause chronic mesenteric ischemia and postprandial abdominal pain) and thrombosis (which can cause acute mesenteric ischemia, a surgical emergency). Elevated peak systolic velocities at the SMA origin suggest significant stenosis. The SMA also has a characteristic waveform that changes from high-resistance during fasting to low-resistance after eating.
Sonography Term