2D Ultrasound Elasticity Imaging of Abdominal Aortic Aneurysms Using Deep Neural Networks

TL;DR

This paper introduces a deep learning framework using 2D ultrasound and finite element simulations to accurately estimate the tissue stiffness of abdominal aortic aneurysms, potentially improving rupture risk assessment.

Contribution

The study presents a novel deep neural network approach with U-Net architecture for elasticity imaging of AAAs, trained on simulated data and validated on phantom and clinical data, enabling rapid tissue stiffness estimation.

Findings

Achieved NMSE of 0.73% in simulated data

Predicted modulus ratios closely match expected values in phantom experiments

Deep learning method offers faster estimates compared to iterative methods

Abstract

Abdominal aortic aneurysms (AAA) pose a significant clinical risk due to their potential for rupture, which is often asymptomatic but can be fatal. Although maximum diameter is commonly used for risk assessment, diameter alone is insufficient as it does not capture the properties of the underlying material of the vessel wall, which play a critical role in determining the risk of rupture. To overcome this limitation, we propose a deep learning-based framework for elasticity imaging of AAAs with 2D ultrasound. Leveraging finite element simulations, we generate a diverse dataset of displacement fields with their corresponding modulus distributions. We train a model with U-Net architecture and normalized mean squared error (NMSE) to infer the spatial modulus distribution from the axial and lateral components of the displacement fields. This model is evaluated across three experimental domains: digital phantom data from 3D COMSOL simulations, physical phantom experiments using biomechanically distinct vessel models, and clinical ultrasound exams from AAA patients. Our simulated results demonstrate that the proposed deep learning model is able to reconstruct modulus distributions, achieving an NMSE score of 0.73\%. Similarly, in phantom data, the predicted modular ratio closely matches the expected values, affirming the model's ability to generalize to phantom data. We compare our approach with an iterative method which shows comparable performance but higher computation time. In contrast, the deep learning method can provide quick and effective estimates of tissue stiffness from ultrasound images, which could help assess the risk of AAA rupture without invasive procedures.