Ultrasound contrast agent microbubble

Microbubble contrast agents are tiny, gas-filled spheres—typically stabilized by a shell of lipid, protein, or polymer—administered intravenously to enhance ultrasound imaging. When subjected to an ultrasound field, microbubbles resonate, strongly scattering and reflecting ultrasound signals (“backscatter enhancement”) due to nonlinear oscillations that depend on their size, shell properties, and acoustic conditions. This resonance effect makes microbubbles highly efficient as contrast agents for diagnostic ultrasound and as facilitators of novel therapies, such as transiently increasing biological barriers (e.g., blood–brain barrier) and improving local drug delivery through mechanisms like stable and inertial cavitation[1][2][4][6]. Microbubble resonance is a biophysical property rather than a biomolecular target and is not specific to a single protein, receptor, or enzyme.

Other names

Microbubble (MB)Ultrasound microbubble contrast agentIntravascular microbubble

Enhancement of ultrasound backscatter via nonlinear resonance Temporary increase in tissue permeability (by cavitation or oscillation) Induction of localized mechanical bioeffects (stable and inertial cavitation)