Color-flow duplex scanning of the leg arteries by use of a new echo-enhancing agent

Abstract

Objective: This was a dose-finding and effectiveness study of a newly developed contrast-enhancing agent, sulphur hexafluoride (SF6), in patients with peripheral arterial disease in whom the therapeutic policy could not be established on the basis of standard color-flow duplex scanning of the leg arteries. Methods: In this open-label, randomized, dose-ranging, crossover design, 14 patients in whom the assessment of vessel patency was difficult because of poor visibility (low-flow state) or extensive wall calcifications were studied. Contrast-enhanced duplex scanning was performed on the upper leg (n = 4), lower leg (n = 6), or pedal (n = 4) arteries after intravenous injection of four different dosages of SF6. The results were compared with those from selective angiography of the vessel of interest. Contrast duration and agreement about the diagnosis and the confidence in the diagnosis were obtained before and after administration of the contrast agent. Results: No adverse effects of the contrast agent were seen. Overall agreement was reasonable with regard to vessel patency between contrast-enhanced duplex scanning and angiography (71%). Nine of 14 vessels (64%) appeared open when contrast was applied. In four cases this could not be confirmed by angiography; in two of these cases this was due to the presence of collateral vessels. All vessels that appeared occluded with the contrast agent were also occluded on the angiogram. The confidence in the diagnosis increased from 56% to 91% after contrast administration (P < .0001). Conclusion: SF6-enhanced color-flow duplex scanning is a safe method that may improve the assessment of the patency of leg arteries, particularly in low-flow states. The visualization of collateral vessles during (enhanced) duplex scanning may be misleading because they may be regarded as the vessel of interest. Copyright © 2002 by The Society for Vascular Surgery and The American Association for Vascular Surgery.