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Contrast-Enhanced Ultrasound (CEUS) is an ultrasound technique that uses microbubble contrast agents to improve visualization of vascularity and perfusion of tissues in real time.

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• Provides dynamic functional information similar to CT/MRI contrast studies but with advantages of US.

Contrast Agents

Composition

• Gas-filled microbubbles (1–10 μm) encapsulated by lipid, protein, or polymer shells
• Gases used: sulfur hexafluoride, perfluorocarbon

Examples

• SonoVue / Lumason (sulfur hexafluoride) – most widely used (EFSUMB/EASL approved)
• Definity, Optison – other FDA-approved agents

Properties

• Intravascular tracers (do not leak into interstitium like CT/MRI agents)
• Excellent safety profile – non-nephrotoxic and no ionizing radiation

Physics / Technique

• Microbubbles oscillate under ultrasound beam → nonlinear echoes.
• Low Mechanical Index (MI) imaging (harmonic imaging) used to detect bubbles.
• Contrast destruction-replenishment techniques assess perfusion kinetics.

Phases of Enhancement (analogous to CT/MRI)