Mathieu Pernot

French Institute of Health and Medical Research | Inserm · Physics for Medicine

Objectives: Monitoring cavitation during ultrasound therapy is crucial for assessing the procedure safety and efficacy. This work aims to develop a self-sensing and low-complexity approach for robust cavitation detection in moving organs such as the heart. Methods: An analog-to-digital converter was connected onto one channel of the therapeutic...

Background: Transcatheter aortic valve replacement (TAVR) was developed for inoperable patients with severe aortic stenosis. However, despite TAVR advancements, some patients remain untreated due to complex comorbidities, necessitating less-invasive approaches. Non-invasive ultrasound therapy (NIUT), a new treatment modality, has the potential to a...

3D Imaging of the human heart at high frame rate is of major interest for various clinical applications. Electronic complexity and cost has prevented the dissemination of 3D ultrafast imaging into the clinic. Row column addressed (RCA) transducers provide volumetric imaging at ultrafast frame rate by using a low electronic channel count, but curren...

Introduction: Takayasu arteritis (TA) is associated with microvascularization of the wall of large arteries and is related to inflammation. Ultrasound localization microscopy (ULM), combining ultrafast ultrasound imaging with microbubble (MB) injection, can track the path of MBs within the arterial wall and thus provide imaging of the vasa vasorum....

Functional ultrasound (fUS) has received growing attention in preclinical research in the past decade, providing a new tool to measure functional connectivity (FC) and brain task-evoked responses with single-trial detection capability in both anesthetized and awake conditions. Most fUS studies rely on 2D linear arrays to acquire one slice of the br...

Blood pressure measurement is the most widely performed clinical exam to predict mortality risk. The gold standard for its noninvasive assessment is the auscultatory method, which relies on listening to the so-called “Korotkoff sounds” in a stethoscope placed at the outlet of a pneumatic arm cuff. However, more than a century after their discovery,...

Background: Coronary microvascular obstruction also known as no-reflow phenomenon is a major issue during myocardial infarction that bears important prognostic implications. Alterations of the microvascular network remains however challenging to assess as there is no imaging modality in the clinics that can image directly the coronary microvascula...

The assessment of myocardial fiber disarray is of major interest for the study of the progression of myocardial disease. However, time-resolved imaging of the myocardial structure remains unavailable in clinical practice. In this study, we introduce 3D Backscatter Tensor Imaging (3D-BTI), an entirely novel ultrasound-based imaging technique that ca...

Objective Early diagnosis and acute knowledge of cerebral disease require to map the microflows of the whole brain. Recently, ultrasound localization microscopy (ULM) was applied to map and quantify blood microflows in 2D in the brain of adult patients down to the micron scale. Whole brain 3D clinical ULM remains challenging due to the transcranial...

Purpose: Aortic maximal rate of systolic distention (MRSD) is a prognosis factor of ascending aorta dilatation with magnetic resonance imaging. Its calculation requires precise continuous tracking of the aortic diameter over the cardiac cycle, which is not feasible by focused ultrasound. We aimed to develop an automatic aortic acquisition using ult...

Objectives Use of sulphur hexafluoride microbubbles (MB) with ultrasound can provide arterial wall enhancement. The use of ultrafast imaging with MB super-localization offers the possibility of ultrasound localization microscopy (ULM) and thus a visualization of in vivo carotid vasa vasorum. We aim to perform in vivo Vasa vasorum imaging in the car...

Background Heart transplantation is the definitive treatment for many cardiovascular diseases. However, no ideal approach is established to evaluate heart grafts and it mostly relies on qualitative interpretation of surgeon based on the organ aspect including anatomy, color and manual palpation. In this study we propose to assess quantitatively the...

Background Non-invasive high-resolution imaging of the cerebral vascular anatomy and function is key for the study of intracranial aneurysms, stenosis, arteriovenous malformations, and stroke, but also neurological pathologies, such as degenerative diseases. Direct visualization of the microvascular networks in the whole brain remains however chall...

Mapping blood microflows of the whole brain is crucial for early diagnosis of cerebral diseases. Ultrasound localization microscopy (ULM) was recently applied to map and quantify blood microflows in 2D in the brain of adult patients down to the micron scale. Whole brain 3D clinical ULM remains challenging due to the transcranial energy loss which s...

Objectives The purpose of this study was to demonstrate 3-dimensional (3D) coronary ultrasound localization microscopy (CorULM) of the whole heart beyond the acoustic diffraction limit (<20 μm resolution) at ultrafast frame rate (>1000 images/s). Background Direct assessment of the coronary microcirculation has long been hampered by the limited sp...

Objectifs L’évaluation actuelle des plaques carotidiennes d’athérosclérose instables reste actuellement difficile et de nouveaux marqueurs de risque sont requis afin d’orienter la décision chirurgicale. Des marqueurs d’analyse des tissus par élastographie pourraient permettre de mieux caractériser la composition de la plaque d’athérosclérose. L’ima...

Ultrafast ultrasound imaging (UUI) provides an estimation of carotid plaque stiffness by shear wave elastography (SWE) and the quantification of wall shear stress (WSS) by ultrafast Doppler. We aimed to evaluate the combined criteria of plaque stiffness and WSS applied on the plaque as potential biomarkers of plaque vulnerability assessed by histol...

Shear wave elastography offers a new dimension to echocardiography: it measures myocardial stiffness. Therefore, it could provide additional insights into the pathophysiology of cardiac diseases affecting myocardial stiffness and potentially improve diagnosis or guide patient treatment. The technique detects fast mechanical waves on the heart wall...

Myocardial stiffness is an intrinsic property of the myocardium that influences both diastolic and systolic cardiac function. Myocardial stiffness represents the resistance of this tissue to being deformed and depends on intracellular components of the cardiomyocyte, particularly the cytoskeleton, and on extracellular components, such as collagen f...

Technologies to visualize whole organs across scales in vivo are essential for our understanding of biology in health and disease. To date, only post-mortem techniques achieve cellular resolution across entire organs. Here, we demonstrate in vivo volumetric ultrasound localization microscopy (ULM). We detail a universal methodological pipeline incl...

Technologies to visualize whole organs across scales in vivo are essential for our understanding of biology in health and disease. To date, only post-mortem techniques achieve cellular resolution across entire organs. 2D ultrasound localization microscopy (ULM) suffers from reprojection issues and out-of-plane motion preventing complex blood flow q...

Background: While aortic valve replacements (AVR) generally present favorable outcomes in severe calcific aortic stenosis (CAS), not all patients are eligible for an invasive treatment.Cardiawave © developed a novel non-invasive ultrasound therapy (NIUT) device, Valvosoft, to treat CAS. A prospective first-in-human study was conducted in two center...

Background Despite overall favourable outcome of surgical and transcatheter aortic valve replacement (SAVR/TAVR) in patients with severe calcific aortic stenosis (CAS), not all patients are eligible for an invasive treatment1 because of too high predicted mortality and complications. Cardiawave© has developed a novel non-invasive ultrasound therapy...

Purpose New biomarkers are needed to assess the vulnerability of carotid plaque to guide carotid surgery decision. Ultrafast Ultrasound Imaging (UUI) provides an estimation of plaque stiffness by Shear Wave Elastography (SWE) and the quantification of wall shear stress (WSS) by ultrafast Doppler. We aimed at evaluating the plaque stiffness and WSS...

Technologies to visualize whole organs across scales in vivo are essential for our understanding of biology in health and disease. To date, only post-mortem techniques such as perfused computed tomography scanning or optical microscopy of cleared tissues achieve cellular resolution across entire organs and imaging methods with equal performance in...

Quantitative assessment of myocardial stiffness is crucial to understand and evaluate cardiac biomechanics and function. Despite the recent progresses of ultrasonic shear wave elastography, quantitative evaluation of myocardial stiffness still remains a challenge because of strong elastic anisotropy. In this paper we introduce a smart ultrasound ap...

Row column addressing (RCA) transducers have the potential to provide volumetric imaging at ultrafast frame rate using a low channel count over a large field of view. In previous works we have shown that vascular imaging of large arteries as well as functional neuroimaging of the rat brain were feasible using RCA orthogonal plane wave imaging (OPW)...

Introduction Ultrafast Ultrasound Imaging (UUI) provides an estimation of carotid plaque stiffness by shear wave elastography (SWE) and the quantification of wall shear stress (WSS) by ultrafast Doppler. Objective We aimed to evaluate the combined criteria of plaque stiffness and WSS applied on the plaque as potential biomarkers of plaque vulnerab...

Changes in cerebral blood flow are associated with stroke, aneurysms, vascular cognitive impairment, neurodegenerative diseases and other pathologies. Brain angiograms, typically performed via computed tomography or magnetic resonance imaging, are limited to millimetre-scale resolution and are insensitive to blood-flow dynamics. Here we show that u...

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Bettencourt Foundation Background/Introduction We demonstrated recently that Ultrafast ultrasound Doppler imaging can image the intramyocardial coronary circulation in beating hearts of large animals and patients [1]. Yet, ultrasound spatial resolution remains lim...

Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): ERC Introduction Myocardial stiffness (MS) is crucial to understand cardiac biomechanics and evaluate cardiac function. We recently demonstrated that shear wave imaging using acoustic radiation force can provide quantitative end-diastolic MS in...

Doppler ultrasound is the premier modality to analyze blood flow dynamics in clinical practice. With conventional systems, Doppler can either provide a time-resolved quantification of the flow dynamics in sample volumes (spectral Doppler) or an average Doppler velocity/power [color flow imaging (CFI)] in a wide field of view (FOV) but with a limite...

Background: Not all patients with severe aortic valve stenosis are eligible for open-heart surgery or TAVR. CARDIAWAVE (Paris, France) has developed Valvosoft, a unique non-invasive ultrasound therapy device to treat aortic stenosis. The therapy aims to improve the opening of severely calcified aortic valves by cracking the calcium and reducing the...

Objectives We recently developed a unique transthoracic non-invasive ultrasound therapy device called Valvosoft to treat aortic stenosis. The therapy consists in delivering trans-thoracically precisely focused and controlled short ultrasound pulses (<20μsec) at a high acoustic intensity to produce non-thermal mechanical tissue softening of the calc...

Calcific aortic stenosis (CAS) is associated with advanced age and comorbidities, therefore a non-invasive therapy for it would be beneficial. We previously demonstrated that ultrasound therapy improved calcified bioprosthetic valve function in an open chest model. For translational applications, we tested non-invasive ultrasound therapy (NIUT) tra...

Introduction Coronary artery disease affecting myocardial perfusion continues to be the leading cause of cardiovascular morbidity and mortality worldwide. While invasive evaluation based on coronary angiography and flow measurements still is considered the reference technique for assessing myocardial perfusion, technological evolutions in noninvasi...

The objectives were to develop a novel three-dimensional technology for imaging naturally occurring shear wave (SW) propagation, demonstrate feasibility on human volunteers and quantify SW velocity in different propagation directions. Imaging of natural SWs generated by valve closures has emerged to obtain a direct measurement of cardiac stiffness....

The objectives were to develop a novel three-dimensional technology for imaging naturally occurring shear wave (SW) propagation, demonstrate feasibility on human volunteers and quantify SW velocity in different propagation directions. Imaging of natural SWs generated by valve closures has emerged to obtain a direct measurement of cardiac stiffness....

Aims Pulsed Cavitational Ultrasound Therapy (thombotripsy) allows the accurate fractionation of a distant thrombus. We aimed at evaluating the efficacy and safety of non‐invasive thrombotripsy using a robotic assisted and high frequency ultrasound approach to recanalize proximal deep venous thrombosis (DVT) in a swine model. Methods Occlusive thro...

Coronary flow rate remains complex to assess in clinical practice using non-invasive, non-ionizing imaging tools. In this study, we introduce 3-D Ultrafast Doppler Coronary Angiography (3-D UDCA), an ultrasound-based method to assess coronary blood flows in three-dimensions at high volume-rate and in one single heartbeat. We demonstrate that 3-D UD...

Objective The degree of stenosis of a carotid plaque is a well-established risk factor for ischemic stroke. Nevertheless, the risk of ipsilateral stroke in asymptomatic carotid stenosis remains low and new imaging markers are needed to better target which patients would benefit most from endarterectomy or intensive medical therapy. Ultrafast ultras...

Funding Acknowledgements European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n° 311025 and the ANR-10-IDEX-00 Background 4D echocardiography has the strong potential to improve cardiac index quantification by providing reproducible and user independent measurements. Quantification of...

Purpose To develop specific aortic sequences in ultrafast ultrasound imaging (UF) to provide access to the aortic MRSD. Methods We used a phased array probe (Supersonic Imagine©) and dedicated sequences at 2000 frames/s developed in the laboratory. Data were analyzed with a created interface (Fig. 1) to automatically track the anterior and posteri...

Background Post thrombotic syndrome is a frequent complication of deep venous thrombosis, associated with high morbidity. Treatments currently available are invasive. Pulsed cavitational ultrasound therapy (PCUT) is a new technique to destroy remotely soft tissue. We demonstrated that PCUT was able to recanalize non-invasively in in-vitro model of...

Objective Carotid plaque vulnerability assessment could guide the decision to perform endarterectomy. Ultrafast ultrasound imaging (UF) can evaluate local flow velocities over an entire 2D image, allowing measurement of the wall shear stress (WSS). We aimed at evaluating the feasibility of WSS measurement in a prospective series of patients with ca...

Functional ultrasound imaging (fUS) recently emerged as a promising neuroimaging modality to image and monitor brain activity based on cerebral blood volume response (CBV) and neurovascular coupling. fUS offers very good spatial and temporal resolutions compared to fMRI gold standard as well as simplicity and portability. It was recently extended t...

Ultrasound techniques currently used in echocardiography are limited by conventional frame rates. Ultrafast ultrasound imaging is able to capture images at frame rates up to 100 times faster compared with conventional imaging. Specific applications of this technology have been developed and tested for clinical use in pediatric and adult cardiac ima...

Aims To compare the carotid stiffness and flow parameters by ultrafast ultrasound imaging (UF), in bicuspid aortic valve (BAV) patients to first-degree relatives (controls). Methods BAV patients (n = 92) and controls (n = 48) were consecutively included at a reference center for BAV. Aortic valve and ascending aorta were evaluated by echocardiogra...

Multi-plane-transmit (MPT) is a matrix array based 3D beamforming methodology, which combines the features of diverging wave compounding (DWC) and multi-line-transmit (MLT). The MPT beams are diverging in one lateral dimension, while focused in the other lateral dimension, leading to a plane-wise reconstruction process. As a result, compounding is...

We extended the capabilities of functional ultrasound to whole-brain four-dimensional (4D) neuroimaging. Our multiplane-wave transmission scheme on matrix arrays at thousands of frames per second provides volumetric recordings of cerebral blood volume changes at high spatiotemporal resolution. We illustrated the approach in rats while providing mul...

Background Carotid plaque vulnerability assessment is an important factor in guiding the decision to treat significant carotid stenosis. Ultrafast Ultrasound Imaging (UF) offers the possibility of evaluating local flow velocities over an entire 2D image, allowing access to velocity measurements in contact with the arterial wall and to measure the w...

Background Post thrombotic syndrome is a frequent complication of deep venous thrombosis and is associated with high morbidity and hospitalization. Treatments currently available are invasive, involve use of endovenous procedures with stents and balloons, and frequently require general anesthesia. Pulsed cavitational ultrasound therapy (PCUT) emerg...

Background Aortic valve stenosis is associated with age and comorbidities, which require exploring less invasive therapeutic approach to improve patient outcome. We previously demonstrated in vitro and in vivo that pulsed cavitational ultrasound therapy (PCUT) can improve calcified bioprosthesis stenosis by softening leaflets remotely. To apply thi...

Background Magnetic resonance imaging allows evaluation of aortic stiffness by the maximum rate of systolic distension (MRSD) a new prognosis factor of aortic dilatation in patients with bicuspid aortic valve (BAV). MRSD requires a continuous monitoring of the aortic diameter during the cardiac cycle, not accessible to conventional echocardiography...

Ultrasound localization microscopy can map blood vessels with a resolution much smaller than the wavelength by localizing microbubbles. The current implementations of the technique are limited to 2-D planes or small fields of view in 3-D. These suffer from minute-long acquisitions, out-of-plane microbubbles, and tissue motion. In this paper, we exp...

Introduction Carotid plaque vulnerability assessment is an important factor in guiding the decision to perform carotid endarterectomy in case of asymptomatic stenosis. Ultrafast Ultrasound Imaging (UUI) offers the possibility of evaluating local flow velocities over an entire 2D image, allowing access to measure the wall shear stress (WSS). Our obj...

Elastic properties of arteries have long been recognized as playing a major role in the cardiovascular system. However, non-invasive in vivo assessment of local arterial stiffness remains challenging and imprecise as current techniques rely on indirect estimates such as wall deformation or pulse wave velocity. Recently, Shear Wave Elastography (SWE...

Objectives The goal of this study was to demonstrate the feasibility of semi-automatic evaluation of cardiac Doppler indices in a single heartbeat on human hearts by performing 4D ultrafast echocardiography with a dedicated sequence of 4D simultaneous tissue and blood flow Doppler imaging. Background 4D echocardiography has the potential to improv...