# Synthetic Elastography using B-mode Ultrasound through a Deep Fully-Convolutional Neural Network

## TL;DR

This paper presents a deep learning method to generate synthetic shear-wave elastography images from conventional B-mode ultrasound, enabling tissue elasticity estimation without specialized SWE hardware.

## Contribution

The authors develop a deep fully-convolutional neural network that produces sSWE images from B-mode images, demonstrating comparable accuracy to real SWE in prostate cancer patients.

## Key findings

- sSWE images have a mean absolute error of 4.5 kPa compared to real SWE
- High-level feature visualization shows overlap across different scanners
- Qualitative analysis suggests potential for elasticity imaging without SWE hardware

## Abstract

Shear-wave elastography (SWE) permits local estimation of tissue elasticity, an important imaging marker in biomedicine. This recently-developed, advanced technique assesses the speed of a laterally-travelling shear wave after an acoustic radiation force "push" to estimate local Young's moduli in an operator-independent fashion. In this work, we show how synthetic SWE (sSWE) images can be generated based on conventional B-mode imaging through deep learning. Using side-by-side-view B-mode/SWE images collected in 50 patients with prostate cancer, we show that sSWE images with a pixel-wise mean absolute error of 4.5+/-0.96 kPa with regard to the original SWE can be generated. Visualization of high-level feature levels through t-Distributed Stochastic Neighbor Embedding reveals substantial overlap between data from two different scanners. Qualitatively, we examined the use of the sSWE methodology for B-mode images obtained with a scanner without SWE functionality. We also examined the use of this type of network in elasticity imaging in the thyroid. Limitations of the technique reside in the fact that networks have to be retrained for different organs, and that the method requires standardization of the imaging settings and procedure. Future research will be aimed at development of sSWE as an elasticity-related tissue typing strategy that is solely based on B-mode ultrasound acquisition, and the examination of its clinical utility.