High-Resolution Ultrasound Imaging Enabled by Random Interference and Joint Image Reconstruction.

Pavel Ni,Heung-No Lee

doi:10.3390/s20226434

Abstract

In ultrasound, wave interference is an undesirable effect that degrades the resolution of the images. We have recently shown that a wavefront of random interference can be used to reconstruct high-resolution ultrasound images. In this study, we further improve the resolution of interference-based ultrasound imaging by proposing a joint image reconstruction scheme. The proposed reconstruction scheme utilizes radio frequency (RF) signals from all elements of the sensor array in a joint optimization problem to directly reconstruct the final high-resolution image. By jointly processing array signals, we significantly improved the resolution of interference-based imaging. We compare the proposed joint reconstruction method with popular beamforming techniques and the previously proposed interference-based compound method. The simulation study suggests that, among the different reconstruction methods, the joint reconstruction method has the lowest mean-squared error (MSE), the best peak signal-to-noise ratio (PSNR), and the best signal-to-noise ratio (SNR). Similarly, the joint reconstruction method has an exceptional structural similarity index (SSIM) of 0.998. Experimental studies showed that the quality of images significantly improved when compared to other image reconstruction methods. Furthermore, we share our simulation codes as an open-source repository in support of reproducible research.

Highlights

Medical imaging refers to different tools and techniques used in hospitals for diagnostic purposes.Noninvasive imaging modalities, ultrasound imaging, play an important role in the early identification of abnormalities
In [22], we proposed a novel interference-based ultrasound imaging method, where instead of a traditional focused ultrasound beam, we use the transmission of an unfocused ultrasound wavefront of random interference
In [22], we proposed an interference-based imaging method that used the compounding of several joint image reconstruction method, we propose directly reconstructing a high‐resolution image by independently reconstructed images given a set of echo signals pi and transmission matrices Gi

Summary

Introduction

Medical imaging refers to different tools and techniques used in hospitals for diagnostic purposes.Noninvasive imaging modalities, ultrasound imaging, play an important role in the early identification of abnormalities. Conventional ultrasound imaging methods use beamforming to spatially divide the region of interest (ROI) into multiple scanlines [1,2]. Conventional ultrasound techniques that utilize beamforming are capable of achieving an image resolution that is approximately equivalent to the width of the transmitted ultrasound beam [3]. Ultrasound interference has been treated as an undesired effect that degrades the quality of ultrasound images. We have recently shown that an ultrasound wavefront of random interference can be used as a means to differentiate between individual point scatterers in the ROI [23]. In conventional ultrasound imaging, beamforming is used to spatially divide the ROI into several scanlines. An ultrasound image is acquired one scanline at a time by using beamforming to focus the transmit and receive ultrasound pulses. Owing to the imperfect coherence of echo signals, the beamformed signal is corrupted by interference patterns known as speckle noise [6,7,8]

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