Comparative Pharmacokinetic Behavior of Levovist with Water-Soluble Contrast Agents
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.
KeywordsContrast Agent Vascular Phase Early Arterial Phase Trast Agent Blood Space
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