Internship offer in cardiac imaging

Internship offer in cardiac imaging



Non-invasive cardiac work assessment with ultrasound stiffness/strain loops

Supervisors: Clément Papadacci, Mathieu Pernot
Location: Physics for medicine, Inserm U1273, 17 rue Moreau 75012 Paris
Contact: clement.papadacci@espci.fr / 01.80.96.33.62
Duration: 6 months
Expected start date: spring 2021

In 2015, heart failure affected 40 million people worldwide. There are two types of heart failure: heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). HFrEF occurs when the ventricle has partially lost its ability of contracting whereas HFpEF occurs when the ventricle does not relax sufficiently during ventricular filling. Despite the urgent clinical need there is simply no method available in the clinic to fully and early detect HFrEF and HFpEF before apparitions of acute symptoms. In both cases, the main pathophysiological effect of heart failures is a modification of myocardial stiffness. The abnormal increase of stiffness was shown to be key to explain heart failure symptomatology during physical exercise of heart failure patients with preserved ejection fraction.

However, assessing only myocardial stiffness may not be sufficient as soft tissues exhibit hyperelastic behavior. Linear relationship from Hook’s law that links stiffness, stress and strain cannot accurately describe myocardium mechanics. Therefore, to obtain the full characterization of the cardiac muscle, at least two of the three physical parameters must be measured.

During the internship, an experimental framework will be developed to evaluate non-invasively, for the first time, Elasticity (or stiffness) – Strain loops (ES loops) in rodents. From ES loop, cardiac work will be measured as the inner surface of the loop and will be validated against invasive Pressure volume loop measurements in rodents.

The intern will develop ultrasound sequences on a research programmable ultrasound scanner to perform shear wave elastography and strain evaluations. The new sequences will be tested on home-made gelatin phantoms. After parameter optimizations, the elasticity and strains will be evaluated in vivo in anesthetized rodents under different cardiac conditions. Processing algorithms will be also developed to process the acquired data to assess cardiac loops and measure cardiac work.

Candidate profile:

  • Interest for preclinical studies
  • Knowledge in signal processing and/or programming (Matlab)
  • Knowledge in acoustic physics/ultrasound
  • Ability to work in a team
  • Student in last year of Master 2 or Engineering school