November 11th, 2025

New Publication: Inverse Problem Approach to Aberration Correction for In Vivo Transcranial Imaging Based on a Sparse Representation of Contrast-Enhanced Ultrasound Data

Paul Xing and co-authors have published a new paper in IEEE Transactions on Biomedical Engineering ( DOI: 10.1109/TBME.2025.3564473). 

In this work, we present an inverse problem approach to aberration correction (IPAC) that leverages the sparsity of microbubble signals.  We propose to use the a priori knowledge of the medium based upon microbubble localization and wave propagation to build a forward model to link the measured signals directly to the aberration function. We showed that IPAC can perform skull-induced aberration correction and improved power Doppler as well as ULM images acquired on the mouse brain

September 18th, 2025

7 papers at the IEEE International Ultrasonics Symposium

We were happy to present our work at IUS this year! Jonathan and Paul showed how weak and strong aberrations caused by the skull could be corrected for in a practical, repeatable manner. Alice and Stephen presented how long ensemble processing could enable better pulse wave velocity measurements and vessel labelling. Oleksandra presented her novel high frequency theragnostic approach for BBB opening an monitoring using dynamic ULM. Nin revealed our soon-to-be-released giant dataset of in vivo mouse brain acquisition, which Brice leveraged to demonstrate the benefits of using in vivo data to develop deep-learning reconstruction strategies. Finally, Alexis described his realistic simulation framework to improve cardiac dynamic ULM in humans. Stay tuned for the associated publications! 

September 10th, 2025

New Publication: 3D transcranial Dynamic Ultrasound Localization Microscopy in the mouse brain using a Row-Column Array

Alice Wu and co-authors have published a new paper in IEEE Transactions on Biomedical Engineering (online ahead of print; DOI: 10.1109/TBME.2025.3598693). 

In this work, we demonstrate a first-of-its-kind 3D+t Dynamic Ultrasound Localization Microscopy (DULM) protocol using a Row-Column Array (RCA) to measure blood flow in the whole mouse brain transcranially with both high spatial and temporal resolution. The technique acquires volumetric images at 750 Hz using 42 tilted plane waves, enabling super-resolved density and velocity maps of the 3D brain vascular network. 

May 28th, 2025

Our Team Shines at the Québec Medical Imaging Symposium 2025 

Université Laval’s Centre de recherche en données massives (CRDM) hosted the second edition of its symposium on medical imaging, organized in collaboration with the Réseau de bio-imagerie du Québec (RBIQ) and the Réseau santé numérique (RSN).

• We are proud to share that eight members of the lab presented their work during this event, showcasing the diversity and excellence of our ongoing research.

• A special congratulations to Professor Jean Provost, who received the Rising Star Award in Bio-imaging, and to Alexis Leconte, PhD student, who was honored with the Best Student Oral Presentation Award.

April 2nd, 2025

Our PhD Students at the First Edition of Polycongré!

The first edition of Polycongré was recently held at Polytechnique Montréal, providing a unique platform to showcase student research—organized by students, for students.

Three PhD students from our lab had the opportunity to present their work:

• Alice presented her research with a poster,

• Alexis also presented a poster and served as session chair for multiple sessions,

• Oleksandra gave an oral presentation.

Congratulations to them for their contributions and for representing the lab at this promising first edition of Polycongré!

March 24th, 2025

New publication: Pruning Sparse Tensor Neural Networks Enables Deep Learning for 3D Ultrasound Localization Microscopy  

Brice Rauby and co-authors have published a new paper in IEEE Transactions on Image Processing.

In this work,  we propose the use of sparse tensor neural networks to enable deep learning-based 3D ULM by improving memory scalability with increased dimensionality. In 3D, the proposed approach reduces memory requirements by two order of magnitude while largely outperforming conventional ULM in high concentration settings. We show that Sparse Tensor Neural Networks in 3D ULM allow for the same benefits as dense deep learning based method in 2D ULM i.e. the use of higher concentration in silico and reduced acquisition time.

February 11th, 2025

Alexis presented his work at Polytechnique’s Biomedical Department

Alexis had the opportunity to present his research at the Biomedical Engineering Department of Polytechnique Montréal as part of Pizza BiomedThis informal event allows biomedical engineering students to learn about ongoing research in their field.

Alexis shared his work and engaged in discussions with students, providing them with insight into current scientific advancements. A great initiative to bridge the gap between research and the next generation of biomedical engineers!

February 4th, 2025

New publication: A Tracking Prior to Localization Workflow for Ultrasound Localization Microscopy  

Alexsi Leconte and co-authors have published a new paper in IEEE Transactions on Medical Imaging.

In this work, we propose a Tracking prior to Localization (TAL) workflow for Ultrasound Localization Microscopy (ULM). Unlike the conventional Localization and Tracking (LAT) approach—where microbubbles are first localized and then tracked—our method first estimates the motion of microbubbles and subsequently performs localization along their predicted trajectories. This inversion of the workflow improves robustness in high-concentration conditions, where overlapping signals make localization challenging. Through both in silico and in vivo experiments, we demonstrate that the TAL framework enhances vessel reconstruction, increases localization accuracy, and provides more reliable velocity maps compared to traditional approaches.

December 20th, 2024

New Publication: 3D ultrasound localization microscopy of the nonhuman primate brain

Paul Xing and co-authors have published a new paper in EBioMedicine. 

In this work, we tested the feasibility of 3D ULM of the nonhuman primate (NHP) brain with a single 256-channel programmable ultrasound scanner. We achieved a highly resolved vascular map of the macaque brain at large depth (down to 3 cm) in presence of craniotomy and durectomy using an 8-MHz multiplexed matrix probe. We were able to distinguish vessels as small as 26.9 𝜇m. We also demonstrated that transcranial imaging of the macaque brain at similar depth was feasible using a 3-MHz probe and achieved a resolution of 60 𝜇m.

September 30th, 2024

The laboratory was present at IEEE IUS Taiwan 2024

Our team recently took part in the IEEE IUS conference in Taiwan. The event was an opportunity to present our work, exchange ideas with experts in the field and discover another part of the world. An enriching experience that motivates us for the future!

September 17th, 2024

New publication: Deep Learning in Ultrasound Localization Microscopy: Applications and Perspectives  

Brice Rauby and co-authors have published a new paper in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

we propose a comprehensive review of the diversity of deep learning applications in ULM focusing on approaches assuming a sparse microbubble distribution. We first provide an overview of how existing studies vary in the constitution of their datasets or in the tasks targeted by the deep learning model. We also take a deeper look into the numerous approaches that have been proposed to improve the localization of microbubbles since they differ highly in their formulation of the optimization problem, their evaluation, or their network architectures. We finally discuss the current limitations and challenges of these methods, as well as the promises and potential of deep learning for ULM in the future.

August 30th, 2024

First participation at a Gordon Research Conference 

We had the pleasure of taking part for the first time in a Gordon Research conference : In Vivo Ultrasound Imaging Conference.

Jean gave an invited presentation on the laboratory's work, and Alexis, Alice and Nin presented their posters.

May 15th, 2024

Our lab will be present at ISBI in Athens

Thrilled to announce that Stephen and Paul, two members from our laboratory  will present their latest research at ISBI in Athens !

February, 2024

New Publication: Phase Aberration Correction for In Vivo Ultrasound Localization Microscopy Using a Spatiotemporal Complex-Valued Neural Network

Paul Xing and co-authors have published a new paper in IEEE Transactions on Medical Imaging. 

In this work, we proposed a deep learning approach based on recently introduced complex-valued convolutional neural networks (CV-CNNs) to retrieve the aberration function, which can then be used to form enhanced images using standard delay-and-sum beamforming. 3D spatiotemporal convolutions were used for the network to leverage entire microbubble tracks. The CV-CNN was more robust than the coherence-based method and could perform aberration correction in a 6-month-old mouse.

November 9th, 2023

Chloé, Stephen and Paul honored at PolyChrome Gala

Three of our colleagues were honoured at the Polychrome Gala for their achievements: 

• Chloé, for first prize in the Fernand-Seguin scholarship (Association des communicateurs scientifiques du Québec)

• Stephen, for the Banting Postdoctoral Fellowship (Government of Canada)

• Paul, for the Canada Graduate Scholarship at the doctoral program (NSERC)

December 14th, 2022

Article in 'Curium' magazine!

Chloé had the opportunity to talk about her research and science journalism activities in Curium magazine, on the occasion of receiving the Relève étoile Louis-Berlinguet award from the Fonds de recherche du Québec - Nature et technologie (FRQNT)! This award was given to her following the publication of her very first paper, "In Vivo Pulsatility Measurement of Cerebral Microcirculation in Rodents Using Dynamic Ultrasound Localization Microscopy", published in IEEE TMI in April 2022.

May 17th, 2022

Article in "l'Actualité" magazine!

Chloé was awarded the 29th Acfas Research Popularization Competition text format a few days ago. Her text was published by the magazine l'Actualité, in an article entitled "Dementia: better understanding the role of blood circulation". 

October 9th, 2019

Chloé's presentation at IEEE IUS 2019

Chloé could present her work, “Pulsatlity mapping using time-resolved ultrasound localization microscopy in the rodent’s brain in vivo”, at the IEEE IUS 2019 international conference in Glasgow, Scotland. On that occasion, she was able to give an oral presentation on her first results of 2D in vivo pulsatility measurement in the rat brain, and show the first images of Dynamic Ultrasound Localization Microscopy. This 4-day conference was also an opportunity to discover the work in progress in the field of ultrasound medical imaging, and more particularly in brain imaging and Localization Microscopy.

September 6th, 2019

Chloé, Philippe and Hatim at the Engineering Physics Day at Polytechnique Montréal

Chloé, Hatim and Philippe could present their work during the Physics Day, organised at Polytechnique Montréal. Hatim obtained the first price at the competition for the best poster. Congratulations to all three!

June 19th, 2019

Chloé's presentation at the 22nd Research Day at the Montreal Heart Institute

Chloé could present her work during a poster session for the 22nd Research Day, that took place at the Cardiology Institute of Montreal (ICM). During that day, which is a science outreach competition organized for students, postdoctoral fellows, residents and research supervisors, she could connect with doctors, specialists in atherosclerosis, but also patients who suffered from cardiovascular disease.