The objective of this thesis is to investigate and develop high-performance ASIC and ADC prototypes under practical constraints for emerging ultrasound imaging system-on-a-chip (SoC). Innovation and optimization of this study proceed in two directions. In one direction, we focus on miniaturization and integration of the front-end ASIC. We also develop the on-chip transmit micro-beamforming technique, which enables ultrasound systems to control the steering angle of the phased array and further improve the SNR. The ASICs are designed for side-looking (SL)-IVUS, but the presented approaches are equally applicable in a forward-looking (FL)-IVUS probe or other miniature probes, such as intracardiac echography (ICE) catheters. The other direction concentrates on high-performance ADC and communication. Specifically, we develop a compressed sensing framework for full-channel radio frequency (RF) communications, enabling multi-modal, high-resolution, high-frame rate ultrasound imaging in a low-power integrated SoC. Through the investigation of various aspects of integrated circuits for ultrasound imaging systems, this thesis aims to explore their limitations further and provide potential solutions to current design challenges. This research also lays the foundation for the next generation of front-end ASICs for ultrasound imaging systems, especially for wearable, portable, and implantable systems.