A5056954765- Seismic Imaging and Inversion Techniques
- Ultrasound Imaging and Elastography
- Seismic Waves and Analysis
- Ultrasonics and Acoustic Wave Propagation
- Photoacoustic and Ultrasonic Imaging
- Medical Imaging Techniques and Applications
- Electrical and Bioimpedance Tomography
- Flow Measurement and Analysis
- Optical measurement and interference techniques
- Geophysical Methods and Applications
- Advanced Measurement and Metrology Techniques
- Sparse and Compressive Sensing Techniques
- Hydraulic Fracturing and Reservoir Analysis
- Groundwater flow and contamination studies
- Drilling and Well Engineering
ETH Zurich
2020-2024
Board of the Swiss Federal Institutes of Technology
2022
Full-waveform inversion (FWI) for ultrasound computed tomography is an advanced method to provide quantitative and high-resolution images of tissue properties. Two main reasons hindering the widespread adoption FWI in clinical practice are (1) its high computational cost (2) requirement a good initial model mitigate non-convexity inverse problem. The latter commonly referred as "cycle-skipping", which occurs phase differences between synthetic observed signals usually traps local minimum....
We present a full-waveform inversion (FWI) of an in-vivo data set acquired with transmission-reflection optoacoustic ultrasound imaging platform containing cross-sectional slice through mouse. FWI is high-resolution reconstruction method that provides quantitative images tissue properties such as the speed sound. As iterative data-fitting procedure, relies on ability to accurately predict physics wave propagation in heterogeneous media account for non-linear relationship between ultrasonic...
We present an acoustic multi-stage full-waveform inversion (FWI) using in-vivo data of a mouse, acquired with transmission-reflection ultrasound. Our method (1) provides high-resolution images the sound speed in soft tissue and bone, (2) significantly sharpens reflection by reconstructed map as background model, (3) quantifies resolution lengths. The computational cost inherent to standard FWI is reduced applying source encoding. show that this approach results aberration-corrected image....
An alternative approach to acquire transmission travel time data is proposed, exploiting the geometry of devices commonly used in ultrasound computed tomography for medical imaging or non-destructive testing with ultrasonic waves. The intent (i) shorten acquisition a large number emitters, (ii) eliminate calibration step, and (iii) suppress instrument noise. Inspired by seismic ambient field interferometry, method rests on active excitation diffuse wavefields extraction deterministic...
Ultrasound computed tomography (USCT) is a promising imaging modality for breast cancer screening. Two challenges commonly arising in time-of-flight USCT are (1) to efficiently deal with large data sets and (2) effectively mitigate the ill-posedness an adequate reconstruction of model. In this contribution, we develop optimization strategy based on stochastic descent method that adaptively subsamples data, analyze its performance combination different sparsity-enforcing regularization...
Characterizing the spatial resolution and uncertainties related to a tomographic reconstruction are crucial assess its quality assist with decision-making process. Bayesian inference provides general framework compute conditional probability density functions of model space. However, analytic expressions closed-form solutions for posterior limited linear inverse problems such as straight- ray tomography under assumption Gaussian prior data noise. Resolution analysis uncertainty...
We present a novel approach to obtain time-of-flight measurements between transducer pairs in an Ultrasound computed tomography (USCT) scanner by applying the interferometry principle, which has been used success- fully seismic imaging recover subsurface velocity structure from ambient noise recordings. To apply this USCT aperture, random wavefields are generated activating emitting transducers sequence. By correlating signals recorded receiving transducers, we approximation of Green's...
<div> <p>We propose a translation of widely-used seismic ambient noise tomography to active in medical ultrasound. This is intended eliminate time-consuming transducer calibration and improve illumination the target.</p> <p>Ultrasound computed (USCT) an emerging visualization modality imaging especially apt screen soft human tissue such as breast. Currently, USCT applications are developed for breast cancer detection using collection...
An alternative approach to ultrasound computed tomography (USCT) for medical imaging is proposed, with the intent (i) shorten acquisition time devices a large number of emitters, (ii) eliminate calibration step, and (iii) suppress instrument noise. Inspired by seismic ambient field interferometry, method rests on active excitation diffuse ultrasonic wavefields extraction deterministic travel information inter-station correlation. To reduce stochastic errors accelerate convergence, ensemble...