Optically Generated Ultrasound for Intracoronary Imaging

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Optical Physics

Background:

• Conventional intravascular ultrasound (IVUS) faces challenges in miniaturization, cost, and integrating multimodality imaging for molecular characterization.
• Limitations include achieving high sensitivity, broad bandwidths, and incorporating optical elements for photoacoustics (PA) or near-infrared spectroscopy (NIRS) within intracoronary device constraints.

Purpose of the Study:

• To introduce and evaluate Optical Ultrasound (OpUS) as a new paradigm for intracoronary imaging.
• To demonstrate the potential of OpUS to overcome the limitations of conventional IVUS technology.

Main Methods:

• OpUS utilizes a fiber optic transducer where ultrasound is generated via the photoacoustic effect from light absorption in a surface coating.
• Ultrasound waves are converted to thermal energy, causing a pressure rise and propagating ultrasound.
• Ultrasound reflections are received using optical interferometry.

Main Results:

• OpUS achieved high bandwidths (31.5 MHz) and pressures (21.5 MPa).
• Enabled imaging with axial resolutions better than 50 μm and penetration depths exceeding 20 mm.
• Demonstrated performance comparable or superior to conventional 40 MHz IVUS technology.

Conclusions:

• OpUS presents a promising new approach for intracoronary imaging, offering improved resolution and depth.
• Nanocomposite coating materials facilitate multimodality imaging for in-vivo molecular characterization.
• OpUS shows significant potential for future clinical applications in cardiovascular imaging.