Visualizing the Tumor Microvasculature With a Nonlinear Plane-Wave Doppler Imaging Scheme Based on Amplitude...

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Biomedical Engineering

Background:

• Plane wave ultrasonic imaging allows combined Doppler and microbubble contrast imaging, preserving flow sensitivity.
• Current methods struggle to differentiate tissue signals from perfusion due to limited contrast-to-tissue ratio (CTR).

Purpose of the Study:

• To adapt amplitude modulation (AM) for Doppler processing to improve CTR in ultrasound contrast imaging.
• To evaluate AM Doppler's efficacy in separating microbubble signals from tissue signals compared to pulse inversion (PI) Doppler.

Main Methods:

• Developed and applied an amplitude modulation Doppler sequence for ultrasound imaging.
• Compared AM Doppler with pulse inversion Doppler in vitro and in vivo.
• Assessed the contrast-to-tissue ratio (CTR) and velocity estimation accuracy.

Main Results:

• Amplitude modulation Doppler achieved a higher CTR than pulse inversion Doppler.
• Both AM Doppler and PI Doppler provided similar velocity estimates with proper RF echo bandwidth compensation.
• AM Doppler successfully visualized conduit flow and capillary perfusion in vivo at high frame rates.

Conclusions:

• Amplitude modulation Doppler offers improved contrast for microbubble-enhanced ultrasound imaging.
• This technique enhances the differentiation of perfusion from tissue signals, enabling real-time visualization of complex vascular structures.
• AM Doppler shows promise for advanced applications like in vivo tumor imaging.