Comparative Pharmacokinetic Behavior of Levovist with Water-Soluble Contrast Agents

Abstract

As detailed earlier, Levovist produces fragile microbubbles lacking shells. Therefore, the pharmacokinetics of Levovist is quite different from those of water-soluble contrast agents. The enhancement patterns observed on computed tomography (CT), angiography, and dynamic magnetic resonance imaging (MRI) do not apply to contrast-enhanced ultrasonography (US) with Levovist. In a certain way, the behavior of Levovist is similar to that of water-soluble contrast agents during the arterial phase, but its subsequent behavior is very different. Table 6–1 broadly summarizes the differences between contrast agents. Water-soluble contrast agents are regarded as free-pass or through-pass type contrast agents. They can freely pass through the thinnest capillaries in the body. It is known that water-soluble contrast agents leak into the extravascular inter-stitium during the delayed phase, which may result in the false-positive diagnosis of fibrotic changes. However, the dynamic behavior during the 2–3 min from early to late phase is generally described as free pass.