A unified framework combining coherent compounding, harmonic imaging and angular coherence for simultaneous high-quality B-mode and tissue Doppler in ultrafast echocardiography

TL;DR

This paper presents a real-time unified framework that combines coherent compounding, harmonic imaging, and angular coherence to enhance ultrafast echocardiography image quality, effectively handling motion and improving contrast in both in vitro and in vivo tests.

Contribution

It introduces the first real-time integration of these three techniques, demonstrating improved image contrast and quality during high-motion cardiac imaging.

Findings

High contrast achieved up to 17 cm/s in vitro

Significant contrast improvement during cardiac filling in vivo

Unified framework enables high-quality imaging during rapid tissue motion

Abstract

Various methods have been proposed to enhance image quality in ultrafast ultrasound. Coherent compounding can improve image quality using multiple steered diverging transmits when motion occurring between transmits is corrected for. Harmonic imaging, a standard technique in conventional focused echocardiography, has been adapted for ultrafast imaging, reducing clutter. Coherence-based approaches have also been shown to increase contrast in clinical settings by enhancing signals from coherent echoes and reducing clutter. Herein, we introduce a simple, unified framework that combines motion-correction, harmonic imaging, and angular-coherence, showing for the first time that their benefits can be combined in real-time. Validation was conducted through in vitro testing on a spinning disk model and in vivo on 4 volunteers. In vitro results confirmed the unified framework capability to achieve high contrast in large-motion contexts up to 17 cm/s. In vivo testing highlighted proficiency in generating images of high quality during low and high tissue velocity phases of the cardiac cycle. Specifically, during ventricular filling, the unified framework increased the gCNR from 0.47 to 0.87 when compared against coherent compounding.