SHU508A (galactose microparticles) as a contrast agent during endoscopic ultrasound (EUS)

Purpose: To evaluate the utility of a suspension of galactose microparticles available as SHU508A or Levovist as a contrast agent during EUS. Methods: Three sets of experiments were performed on three 20-25 kg. swine (Sus scrofa) under general anesthesia. Upper EUS was performed with an echoendoscope with color Doppler capability (Pentax FG32UA). The celiac artery, superior mesenteric artery (SMA), aorta, portal vein (PV), pancreas, renal pelvis and the G1 wall were imaged by EUS. Multiple intravenous bolus injections of 400 mg/ml of SHU508A were made and its effect on color Doppler and gray scale during EUS was studied. Results: Following contrast injection there was a significant, visually noticeable enhancement of color Doppler signals from the celiac artery, SMA, portal vein and the renal pelvis. Vessels with weak to no color Doppler signals before injection of SHU508A, e.g. celiac artery and SMA, were observed to have strong color signals after injection. The effect of SHU508A on color Doppler was easily appreciated subjectively without the need of complex quantitative measurements. No visually noticeable color Doppler enhancement was seen in vessels such as the aorta which had a very pronounced color Doppler signal even prior to the injection of contrast. Conclusion: Intravenous SHU508A as a contrast agent significantly enhances color Doppler signals during EUS. Such vascular contrast could play a significant role in: (1) increasing the accuracy of EUS in the detection of vascular thrombosis (e.g. portal vein, splenic vein), (2) Aiding detection of malignant vascular invasion (e.g. celiac artery, SMA), and (3) Identification of questionable vascular structures.