PROJECTS

 

The Villemain lab runs a translational program. Starting with the development of a technology, the lab’s objective is to test its application and potential within a pre-clinical project (in vitro or animal model) and then to confirm its potential through clinical application studies. Click through the tabs below to learn more about how the Villemain Lab is using Ultrafast Ultrasound Imaging in different areas of medicine.

The team hopes to apply these new diagnostic tools in different areas of medicine to ultimately improve patient care.

Cardiology

Specific applications of Ultrafast Imaging have been developed and tested for clinical use in paediatric and adult cardiac imaging. These include Ultrafast Doppler or vector flow imaging, shear wave imaging (assessment of tissue stiffness), electromechanical wave imaging and backscatter tensor imaging (assessment of fiber orientation).

Ultrafast ultrasound has great clinical potential in the assessment of cardiac function, in noninvasive hemodynamic analysis, while providing novel techniques for imaging coronary perfusion and evaluating rhythm disorders.

Possible applications of Ultrafast Ultrasound Imaging in pediatric cardiology
Possible applications of ultrafast ultrasound imaging in pediatric cardiology

Neurology

Ultrafast Ultrasound Imaging is able to produce images of the neonate brain vasculature with a high spatial resolution (down to 250 micrometers) and high temporal resolution (<1 millisecond). This allows the detection of many vascular abnormalities such as the beginning of an intraventricular hemorrhage. This imaging allows for the quantification of blood flow in the images, whereas conventional ultrasound scanners (the technology currently used in almost all clinical devices) can either display an image or quantify an area, but not both at once.

With Ultrafast Ultrasound Imaging, it becomes possible to follow fluctuations in blood velocity during the cardiac cycle, in both big arteries and small vessels. Many indicators can be derived from this information, such as the Resistivity Indexes ((Vmax – Vmin)/Vmax) which enables venous and arterial flow distinction and has been known to have strong diagnostic significance.

New emerging techniques also take advantage of the high spatial resolution produced using Ultrafast Ultrasound Imaging. This can help quantify a human’s vascular network in term of number of nodes and branches. Other features of Ultrafast Ultrasound Imaging such as Shear Wave Elastography can reveal tissue stiffness which can be another parameter of interest for diagnostic applications.

Brain perfusion and Ultrafast Ultrasound Imaging
A resistivity map of brain perfusion was obtained using Ultrafast Doppler imaging

Hepatology

For the past 15 years, ultrasound elastography has made it possible to accurately and noninvasively quantify liver stiffness, whether by external mechanical stimulus used in the Fibroscan, or by remote palpation used by other shear wave elastography techniques.

Initially developed to better diagnose liver fibrosis, some confounding factors such as cardiac congestion initially hindered radiologists or hepatologists. Then, they eventually took advantage of it. Understanding the filling pressures of the right heart with the analysis of hepatic congestion made sense. Before elastography, clinicians had to palpate the liver and make a subjective analysis. With
elastography, clinicians now have an objective and noninvasive tool for quantitatively analyzing liver stiffness.

Factors that impact liver stiffness include Centrolobular fibrosis, portal fibrosis, cholestasis, portal blood flow, inflammation, sinusoidal fibrosis
There is a quantitative link between the liver stiffness and right atrial pressure

Nephrology

In nephrology, microperfusion and tissue stiffness are two parameters that are still difficult to assess non-invasively at the patient’s bedside. However, they are fundamental in the analysis and understanding of all types of chronic kidney disease (CKD), particularly in children. Ultrafast Ultrasound Imaging makes it possible to go beyond these limits.

An image produced using shear wave imaging shows kidney elastography.
Quantitative stiffness map of a human kidney using shear wave imaging

Fetal and placenta explorations

Many pathological situations in the relationship between the fetus and the mother, such as intrauterine growth restriction or maternal hypertension, could benefit from a better understanding of placental perfusion and the difference between maternal and fetal blood flow. Ultrasfast Ultrasound Imaging brings new solutions and new perspectives for this.

A diagram shows the lungs and heart of a pregnant woman, and how blood from the heart is pumped into the placenta. From there, the maternal blood flows into the fetus through the umbilical cord.
Placental perfusion, which is the perfusion of the placenta with maternal blood, is a fundamental aspect of the mother-fetus interaction