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Ultrasound echography is, with conventional X-ray, the most widespread medical imaging modality, and its development over the last decade promises an even more important place in the future. Whereas the acquisition of the images, as well as the corresponding diagnostic, are usually performed by a medical doctor holding a probe in his hand, the apparition of flexible ultrasound probes opens new avenues for this modality, in particular in terms of continuous monitoring of the patient. Indeed, it has been demonstrated that manufacturing and imaging with such probes is possible [1]. Flexible arrays can be presented as a patch directly fixed on the patient’s skin, whose shape adapts to changing conditions. In addition to the necessity of being driven by wearable electronic systems, they need to be optimized for compactness, power consumption, material robustness, etc. The way the data are acquired and the images are reconstructed must also be adapted to take into account the modified geometry of the array. This internship aims to study and develop new solutions for ultrasound image beamforming adapted to flexible arrays.
In the context of this internship, we will have access to new flexible arrays and a driving system to estimate the impact of the surface shape of the array on the imaging quality. Indeed, the standard delay-and-sum beamforming strategy assumes the elements’ known shapes and positions on the array [2], [3]. However, using a flexible array does not permit such hypotheses, and adaptive solutions must be found. Moreover, if the location of the array changes, its shape could change, and an adaptive strategy may be of interest to avoid complex hardware and characterization strategies.
Figure: (left) Illustration of a flexible array [1] and (right) the effect of the shape on the image before/after compensation [2].
In summary, the aims of this course are as follows:
- Conduct a state-of-the-art review of flexible probes in ultrasound imaging, with a focus on beamforming/image reconstruction.
- Identify the best approaches in the literature and reprogram them to have a reference to the state of the art.
- Propose a new self-calibrating beamforming approach using flexible probes with an unknown surface shape.
- Test all the approaches on the experimental system provided.
General information
Profile: Student from a top engineering school or research master’s degree (generalist or EEA profile)
Technical skills: image and signal processing. Ultrasound imaging knowledge is a plus.
Soft skills: Versatility and curiosity, ability to work independently, initiative, good written and oral communication skills.
Start and duration of placement: February/March 2025 for 6 months.
Workplace: Creatis, la Doua campus.
How to apply
Send CV + cover letter + M1/M2 or engineering school transcripts to:
François Varray, Associate Professor, francois.varray@creatis.insa-lyon.fr
Hervé Liegbott, Professor, herve.liebgott@creatis.insa-lyon.fr
References
[1] P. L. M. J. van Neer et al., “Flexible large-area ultrasound arrays for medical applications made using embossed polymer structures,” Nat. Commun., vol. 15, no. 1, p. 2802, Mar. 2024, doi: 10.1038/s41467-024-47074-1.
[2] T. Noda, N. Tomii, K. Nakagawa, T. Azuma, and I. Sakuma, “Shape Estimation Algorithm for Ultrasound Imaging by Flexible Array Transducer,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control, vol. 67, no. 11, pp. 2345–2353, Nov. 2020, doi: 10.1109/TUFFC.2020.3004052.
[3] J. Elloian, J. Jadwiszczak, V. Arslan, J. D. Sherman, D. O. Kessler, and K. L. Shepard, “Flexible ultrasound transceiver array for non-invasive surface-conformable imaging enabled by geometric phase correction,” Sci. Rep., vol. 12, no. 1, p. 16184, Sep. 2022, doi: 10.1038/s41598-022-20721-7.