Design and implementation of a multifunctional FPGA-based system for intravascular ultrasound imaging and therapy

Coronary artery disease is a leading cause of death, with 17.8 million deaths globally. Intravascular ultrasound (IVUS) imaging is used to characterize coronary lesions and guide intervention in the cardiac catheterization lab. Separately, catheter-directed thrombolysis provides therapeutic ultrasound in an intravascular form factor to treat clots. In this paper, we propose to develop a flexible, multifunctional, FPGA-based pulser/receiver system for combined IVUS imaging and therapy. The novel system consists of a computer with a Matlab-based graphical user interface, an FPGA board and a custom proprietary board. An example therapy excitation is shown for a 1000-cycle, 550 kHz output waveform with an amplitude of 102 Vpp. This excitation was applied to a custom 3 mm therapy transducer, resulting in hydrophone-measured peak negative acoustic pressure of 305.28 kPa, a mechanical index of 0.41, I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">spta.3</inf> of 5.64 mW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sppa.3</inf> of 310.36 mW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. For imaging, the system can produce waveforms such as a 160 Vpp 1-cycle, 16.67 MHz sinusoidal pulse with a -6 dB bandwidth of 21 MHz. Thus, the developed system can be used to drive simultaneous IVUS imaging to assess the coronary environment and provide image-guided therapy of clots or plaques.