An Annular CMUT Array and Acquisition Strategy for Continuous Monitoring.

Area of Science:

• Biomedical Engineering
• Ultrasound Technology
• Medical Device Development

Background:

• Wearable ultrasound offers continuous monitoring, crucial for applications like high-risk pregnancy fetal monitoring.
• Conventional ultrasound scanners require operators, limiting continuous, independent assessments.
• Existing technology faces challenges in size, cost, and integration for wearable applications.

Purpose of the Study:

• To propose and evaluate a novel 144-element annular capacitive micromachined ultrasonic transducer (CMUT) for 3-D ultrasound imaging.
• To investigate the use of a Fermat's spiral virtual source (VS) pattern for diverging wave transmission to enhance imaging performance.
• To compare the performance of the Fermat's spiral VS pattern against other VS patterns and conventional ultrasound techniques.

Main Methods:

• Development of a simplified, GPU-accelerated simulation framework for ultrasound imaging analysis.
• Characterization of a compact, cost-effective annular CMUT array designed for low-voltage operation and wearable integration.
• Performance comparison of Fermat's spiral VS transmission with focused and plane wave techniques using the simulation framework.

Main Results:

• The simulation framework demonstrated high accuracy, with Mean Absolute Error (MAE) between 0.002 and 0.089.
• Fermat's spiral VS transmission provided a balanced performance across multiple metrics.
• The proposed VS pattern outperformed focused wave transmissions for the specific CMUT aperture studied.

Conclusions:

• The developed CMUT is a foundational component for cost-effective, compact 2-D transducers suitable for 3-D ultrasound imaging.
• The Fermat's spiral VS pattern shows promise for enhancing diverging wave transmission in ultrasound.
• The study establishes a framework for future wearable ultrasound devices, particularly for continuous patient monitoring.