Real-Time Coded Excitation Imaging Using a CMUT-Based Side Looking Array for Intravascular Ultrasound.

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Ultrasound Technology

Background:

• Intravascular ultrasound (IVUS) is crucial for visualizing vessel walls and atherosclerotic plaques.
• Current IVUS methods face limitations in penetration depth and signal-to-noise ratio (SNR).

Purpose of the Study:

• To investigate the efficacy of coded excitation (CE) in phased-array IVUS for enhanced imaging.
• To improve penetration depth and SNR using a novel capacitive micromachined ultrasound transducer (CMUT) array.

Main Methods:

• Development of a 96-element broadband CMUT array for a 1.2-mm diameter catheter tip.
• Characterization of array performance, including -6-dB bandwidth (25 MHz) and center frequency (20 MHz).
• Design of a linear frequency modulation code for improved penetration and resolution via mismatched filter reconstruction.

Main Results:

• Achieved 60-μm axial resolution with short pulse and 70-μm with coded signal on a wire phantom.
• Demonstrated an 8 dB SNR gain for CE imaging.
• Real-time IVUS imaging at 20 frames/s with pixel-based beamforming.

Conclusions:

• Coded excitation significantly enhances SNR and resolution in IVUS imaging.
• The developed CMUT-based system offers improved plaque visualization capabilities.
• This technology holds promise for more detailed intravascular diagnostics.