Reduced-wire readout systems-on-chip for high-frequency intravascular ultrasound imaging

Abstract

The objective of the proposed research is to minimize and integrate intravascular ultrasound imaging (IVUS) system on a guidewire and to develop wireless data communication for general capacitive micromachined ultrasonic transducer (CMUT) based ultrasound imaging system. Several innovative system- and circuit-level techniques are proposed towards the development of CMUT modeling, optimizing front-end circuits, wireless data communication, and inductive power transmission to reduce the system size and the required number of interconnections. Since it provides real-time and high-resolution images of the arteries with negligible side effects, intravascular ultra- sound (IVUS) has been a common imaging modality for cardio-vascular interventions. Current solid-state IVUS catheters (3F-8.2F in diameter) are bulky, cannot reach to lesions in narrow arteries, and require an additional catheter exchange, prolonging the critical cardio-vascular procedures. To address this issue, the way to integrate ASIC and CMUT array on a guidewire by reducing the number of connections is proposed in this research. The proposed research presents three approaches to design and implement the reduced-wire IVUS system: 1) optimized the front-end circuit with properly modeled CMUT equivalent circuits, 2) on-chip quadrature sampler with time-division multiplexing (TDM) based on the synthetic aperture imaging algorithm, and 3) impulse-radio pulse width modulation (IR-PWM) for a wireless data acquisition.