Ultrasonic evaluation of the superior mesenteric artery.

With the use of gray scale B scan ultrasound, it is now feasible in many cases to detect portions of the superior mesenteric artery (SMA) arising from the aorta. Thus, it is possible to measure the aortomesenteric angle and distance. We evaluated a series of patients by ultrasound to determine the normal values for the SMA angle, distance, and lumen diameter. Patients were also examined who had pathological conditions that might produce an alteration in the angle and distance. Abnormal widening was observed in patients with aortic aneurysms and para-aortic lymphosarcomatous nodes. In patients suspected of having duodenal ileus, there was evidence of narrowing of the superior mesenteric artery angle and distance. However, a comparable group of asymptomatic patients of the same age showed a similarly narrowed angle and distance. It was thus concluded that the narrowing of the aortomesenteric angle and distance is not a cause of duodenal ileus. Knowledge of the SMA and aortic lumen diameter has been helpful in selecting the proper catheter and approach for selective arteriography.