Software Solution for Three-Dimensional Dynamic Contrast-Enhanced Ultrasound Imaging using Pulse Inversion Spectral Deconvolution

The use of microbubble (MB) contrast agents and specialized ultrasound (US) techniques during contrast-enhanced ultrasound (CEUS) imaging has been an effective way to visualize blood vessels. Various transmit pulsing and postprocessing schemes are typically used for CEUS imaging to extract the nonlinear MB waveform from the echo signal. However, a new software solution called pulse inversion spectral deconvolution (PISD) has been introduced that can separate tissue and MB signal components without the need for a specific pulse selection. The study detailed herein aims to describe a novel three-dimensional (3-D) PISD-based CEUS imaging system and method. US data was collected using a research scanner (Vantage 256, Verasonics Inc) equipped with a 1024-element matrix array transducer (Vermon) and a vascularized phantom (Model ATS 524, Sun Nuclear) linked serially with a flow pump and mixing chamber filled with a MB contrast agent (Definity, Lantheus Medical Imaging) in water solution. 3-D PISD-based CEUS images were produced offline by custom MATLAB software (Math Works Inc), which involved using a pair of Gaussian derivative functional filters applied to backscattered US channel data before envelope detection and volume reconstruction. A contrast-to-noise ratio (CNR) measure was used to quantify contrast enhancement between PISD and standard B-mode CEUS images of the perfused phantom material. Results showed that 3-D PISD-based CEUS imaging provided a 40 dB increase in vessel enhancement compared to B-mode CEUS images. Overall, these preliminary in vitro findings suggest that 3-D CEUS with PISD postprocessing has potential as a valuable addition to the current vascular imaging techniques.