Ultrasound contrast agents in peripheral vascular disease

Abstract

Driven by rapid technical advances, color-coded Doppler ultrasonography is progressing fast. Early skepticism about the value of the technique has been replaced by growing enthusiasm, and Doppler color flow mapping is now accepted as a valuable aid to the investigation of peripheral arterial and venous disease. In the vast majority of routine investigations the technique has the potential to replace invasive arteriography and phlebography. Despite the ever-increasing sensitivity of ultrasound hardware, visualizing slow-flowing blood vessels in the deeper tissues and detecting flow signals that have been attenuated by overlying calcifications or pockets of bowel gas still poses severe problems. Indeed, the iliac region, the peripheral segments of the deep femoral arteries, the area around the adductor canal and the proximal calf, especially in obese patients, are frequently regarded as inaccessible to ultrasonography. Circulatory problems in these areas affect a certain number of the patients referred to a peripheral vascular disease clinic, so the intense interest in the development of an agent that enhances the Doppler signal from the arteries and veins of the leg is hardly surprising. If that enhancement proves clinically useful, and if it can be produced by a peripheral intravenous injection, it will offer several important advantages over X-ray arteriography. Gray-scale images from the peripheral circulation are too poor, even after enhancement, to give any useful information, and Doppler enhancement is the only effect that has any diagnostic value.

This chapter has been published in Advances in Echo-Enhancement 1997;1:30-42