Ines Elisa Ulrich

Ines Elisa Ulrich

I am a Postdoctoral researcher in computational Seismology in the group Seismology and Wave Physics at ETH Zurich. My primary interests are numerical modelling of acoustic waves, and image reconstruction and I am particularly interested in transferring methods from seismology to biomedical ultrasound.

Publications

Waveform inversion with calibrated source-time functions for improving in-vivo ultrasound computed tomography

Published in SPIE Medical Imaging, 2024, San Diego, California, United States, 2024

This paper is a follow up to our first in-vivo full-waveform paper, demonstrating that by increasing the accuracy of the source-time function that drives ultrasonic wave propagation in the simulation, we are able to increase the resolution of reconstructed features significantly. The source-time functions have thereby been calibrated individually per transducer by an additional source inversion that matches the recorded first arrival waveforms from a reference water shot to the measured data. Including the source inversion within the presented workflow is rather straight forward and therefore the expectation is that ultrasound computed tomography applications would generally benefit form such a calibration step.

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Full-waveform inversion with resolution proxies for in-vivo ultrasound computed tomography

Published in 2023 IEEE International Ultrasonics Symposium (IUS), Montreal, Quebec, Canada, 2023

This paper presents an in-vivo application of full-waveform inversion (FWI) to medical ultrasound data, reconstructing a cross-sectional slice through the abdomen of a mouse. The goal of this study was to push the boundaries of high-resolution FWI for small-scale medical applications. To assess the accuracy of the reconstructed tissue models, we also provide a resolution analysis based on point-spread functions that provides proxies for local resolution lengths. This is essential to accurately interpret reconstructed tissue and anatomical features in a post-processing step.

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Diffuse ultrasound computed tomography

Published in The Journal of the Acoustical Society of America, 2022

This paper describes an alternative method to acquire an ultrasound data set in the setting of breast cancer screening by transferring a method called interferometry from seismic imaging to the small scale medical setup.

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Random field interferometry for medical ultrasound

Published in SPIE Medical Imaging 2020, 2020

Here, we investigate the possibility to apply the interferometic imaging principle developed in seismics to medical ultrasound for breast cancer screening. This paper shows some preliminary results, which are extended to a more rigorous basis in the paper Diffuse ultrasound computed tomography.

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