Systematic Review of Commercially Available Clinical CMUT-Based Systems for Use in Medical Ultrasound Imaging: Products, Applications, and Performance

Abstract

An emerging alternative to conventional piezoelectric technologies, which continue to dominate the ultrasound medical imaging (US) market, is Capacitive Micromachined Ultrasonic Transducers (CMUTs). Ultrasound transducers based on this technology offer a wider frequency bandwidth, improved cost-effectiveness, miniaturized size and effective integration with electronics. These features have led to an increase in the commercialization of CMUTs in the last 10 years. We conducted a review to answer three main research questions: (1) What are the commercially available CMUT-based clinical sonographic devices in the medical imaging space? (2) What are the medical imaging applications of these devices? (3) What is the performance of the devices in these applications? We additionally reported on all the future work expressed by modern studies released in the past 2 years to predict the trend of development in future CMUT device developments and express gaps in current research. The search retrieved 19 commercially available sonographic CMUT products belonging to seven companies. Four of the products were clinically approved. Sonographic CMUT devices have established their niche in the medical US imaging market mainly through the Butterfly iQ and iQ+ for quick preliminary screening, emergency care in resource-limited settings, clinical training, teleguidance, and paramedical applications. There were no commercialized 3D CMUT probes.

Keywords: 4G CMUT; Butterfly IQ; CMUT catheters; CMUT performance; PZT probes; capacitive micromachined ultrasonic transducers; commercial CMUT probes; commercial ultrasound; handheld ultrasound; high-end CMUT probes.

Figure 1

PRISMA methods for systematic study selection.

Figure 2

Population size examined with each CMUT probe: BiQ, BiQ+, and 4G CMUT. Probes that are not visible in the chart did not report the scanned population size in their studies or had a relatively negligible sample size.

Figure 3

Applications and outcome measure statistics: number of studies that focused on each application.