Background and study aims: To evaluate the utility of a suspension of galactose microparticles available as SHU508 A (Levovist) as a contrast agent during endoscopic ultrasonography (EUS).
Materials and methods: Three sets of experiments were performed on three 20-25 kg swine (Sus scrofa) under general anesthesia. Upper EUS was performed with an echo endoscope with color Doppler capability (Pentax FG-32 UA). The celiac artery, superior mesenteric artery, aorta, portal vein, pancreas, and gastrointestinal wall were imaged by EUS. Multiple intravenous bolus injections of 400 mg/ml of SHU508 A were made, and their effect on color Doppler and gray-scale imaging during EUS was studied.
Results: After contrast injection there was a significant, visually noticeable enhancement of the color Doppler signals from the celiac artery, superior mesenteric artery, and portal vein. Vessels with weak to no color Doppler signals before injection of SHU508 A--for example, the celiac artery and superior mesenteric artery--were observed to have strong color signals after injection. The effect of SHU508 A on color Doppler imaging was easily appreciated subjectively without the need for complex quantitative measurements. No visually noticeable color Doppler enhancement was seen in vessels such as the aorta that had a very pronounced color Doppler signal even prior to the injection of contrast. Movement of particulate matter was seen in the portal vein on the gray scale.
Conclusion: Intravenous SHU508 A as a contrast agent significantly enhances color Doppler signals during EUS. Vascualar contrast of this sort could potentially have a significant role in improving the accuracy of EUS in diagnosing malignant vascular invasion, the detection of occult pancreatic neoplasms, and the diagnosis of vascular thrombosis.