Thomas Deffieux

Thomas Deffieux
École Supérieure de Physique et de Chimie Industrielles | ESPCI · Langevin Institute

About

127
Publications
34,619
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Introduction
I develop and investigate new ultrasound imaging modalities as part of my research from physics to signal processing and clinical applications. I work on functional ultrasound imaging of the brain and applications, new probes geometries for 3D ultrafast ultrasound imaging and ultrasound based biomarkers for liver steatosis,

Publications

Publications (127)
Article
In both human and nonhuman primates (NHP), the medial prefrontal region, defined as the supplementary eye field (SEF), can indirectly influence behavior selection through modulation of the primary selection process in the oculomotor structures. To perform this oculomotor control, SEF integrates multiple cognitive signals such as attention, memory,...
Article
Full-text available
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...
Article
Full-text available
Acute spinal cord injury (SCI) leads to severe damage to the microvascular network. The process of spontaneous repair is accompanied by formation of new blood vessels; their functionality, however, presumably very important for functional recovery, has never been clearly established, as most studies so far used fixed tissues. Here, combining ultraf...
Article
Full-text available
The functional imaging within the trigeminal ganglion (TG) is highly challenging due to its small size and deep localization. This study combined a methodological framework able to dive into the rat trigeminal nociceptive system by jointly providing 1) imaging of the TG blood vasculature at microscopic resolution, and 2) the measurement of hemodyna...
Article
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...
Article
Full-text available
Absence of the astrocyte-specific membrane protein MLC1 is responsible for megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare type of leukodystrophy characterized by early-onset macrocephaly and progressive white matter vacuolation that lead to ataxia, spasticity, and cognitive decline. During postnatal development (from P5 to...
Preprint
Full-text available
Acute spinal cord injury (SCI) leads to severe damage to the microvascular network. The process of spontaneous repair is accompanied by formation of new blood vessels; their functionality, however, presumably very important for functional recovery, has never been clearly established, as most studies so far used fixed tissues. Here, combining ultraf...
Preprint
Full-text available
Acute spinal cord injury (SCI) leads to severe damage to the microvascular network. The process of spontaneous repair is accompanied by formation of new blood vessels; their functionality, however, presumably very important for functional recovery, has never been clearly established, as most studies so far used fixed tissues. Here, combining ultraf...
Article
The rise of ultrafast ultrasound imaging - with plane or diverging waves - paved the way to new applications of ultrasound in biomedical applications. Though, propagation through complex layers (typically fat, muscle, and bone) hinder considerably the image quality, especially because of sound speed heterogeneities. In difficult-to-image patients,...
Article
Full-text available
Recent advances in ultrasound imaging triggered by transmission of ultrafast plane waves have rendered functional ultrasound (fUS) imaging a valuable neuroimaging modality capable of mapping cerebral vascular networks, but also for the indirect capture of neuronal activity with high sensitivity thanks to the neurovascular coupling. However, the exp...
Article
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)...
Preprint
Full-text available
Absence of the astrocyte-specific membrane protein MLC1 is responsible for megalencephalic leukoencephalopathy with subcortical cysts (MLC); this rare type of leukodystrophy is characterized by early-onset macrocephaly and progressive white matter vacuolation that lead to ataxia, spasticity, and cognitive decline. During postnatal development (from...
Preprint
Full-text available
The functional imaging of the neurovascular coupling within the trigeminal ganglion (TG) is highly challenging due to its small size and its deep localization. This study combined a methodological framework able to dive into the rat trigeminal nociceptive system by jointly providing first imaging of the trigeminal ganglion blood vasculature at micr...
Article
Full-text available
Aims: Hepatic capillaries are lined with specialised liver sinusoidal endothelial cells (LSECs) which support macromolecule passage to hepatocytes and prevent fibrosis by keeping hepatic stellate cells (HSCs) quiescent. LSEC specialisation is co-determined by transcription factors. The Zinc-Finger E-Box-binding Homeobox (Zeb)2 transcription factor...
Preprint
Full-text available
Recent advances in ultrasound imaging triggered by ultrafast plane waves transmission have rendered functional ultrasound (fUS) imaging a valuable neuroimaging modality capable of mapping cerebral vascular networks, but also to indirectly capture neuronal activity with high sensitivity thanks to the neurovascular coupling. However, the expansion of...
Article
Ultrasound sensitivity to slow blood flow motion gained two orders of magnitude in the last decade thanks to the advent of ultrafast ultrasound imaging at thousands of frames per second. In neuroscience, this access to small cerebral vessels flow led to the introduction of ultrasound as a new and full-fledged neuroimaging modality. Much as function...
Preprint
Full-text available
Pupil dilation is known to be an index of cognitive effort. Nevertheless, our lack of knowledge of the precise dynamics through which pupil size and activity of the medial prefrontal cortex are conjugated during cognitive tasks highlights the need for its further investigation before, during, and after changes in pupil size. Here, we tested whether...
Article
Full-text available
A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-20571-9
Article
Full-text available
During locomotion, theta and gamma rhythms are essential to ensure timely communication between brain structures. However, their metabolic cost and contribution to neuroimaging signals remain elusive. To finely characterize neurovascular interactions during locomotion, we simultaneously recorded mesoscale brain hemodynamics using functional ultraso...
Article
Full-text available
Despite a century of research on the physiology/pathophysiology of the spinal cord in chronic pain condition, the properties of the spinal cord were rarely studied at the large-scale level from a neurovascular point of view. This is mostly due to the limited spatial and/or temporal resolution of the available techniques. Functional ultrasound imagi...
Article
Full-text available
There is a critical need for reliable quantitative biomarkers to assess functional brain alterations in mouse models of neuropsychiatric diseases, but current imaging methods measuring drug effects through the neurovascular coupling, face issues including poor sensitivity, drug-induced changes in global brain perfusion and the effects of anesthesia...
Article
Full-text available
The default mode network (DMN) has been defined in functional brain imaging studies as a set of highly connected brain areas, which are active during wakeful rest and inactivated during task-based stimulation. DMN function is characteristically impaired in major neuropsychiatric diseases, emphasizing its interest for translational research. However...
Article
Full-text available
In the field of ischemic cerebral injury, precise characterization of neurovascular hemodynamic is required to select candidates for reperfusion treatments. It is thus admitted that advanced imaging-based approaches would be able to better diagnose and prognose those patients and would contribute to better clinical care. Current imaging modalities...
Article
Full-text available
Deep regions of the brain are not easily accessible to investigation at the mesoscale level in awake animals or humans. We have recently developed a functional ultrasound (fUS) technique that enables imaging hemodynamic responses to visual tasks. Using fUS imaging on two awake nonhuman primates performing a passive fixation task, we constructed ret...
Article
Full-text available
A shift of paradigm is currently underway in biomedical ultrasound thanks to plane or diverging waves coherent compounding for faster imaging. One remaining challenge consists in handling phase and amplitude aberrations induced during the ultrasonic propagation through complex layers. Unlike conventional line-per-line imaging, ultrafast ultrasound...
Chapter
Full-text available
Numerous diseases find their origin and their diagnosis in the physiological behavior of vascular networks [10]. In particular, to understand the architecture and growth of a tumor the study of blood flows is crucial. Recently, Ultrasensitive Doppler has enabled 4D ultrasound imaging of tumor micro-vasculature in mice [5]. In this study, we propose...
Preprint
Full-text available
Theta and gamma rhythms coordinate large cell assemblies during locomotion. Their spread across temporal and spatial scales makes them challenging to observe. Additionally, the metabolic cost of these oscillations and their contribution to neuroimaging signals remains elusive. To finely characterize neurovascular interactions in running rats, we mo...
Article
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...
Article
The increase of cerebral blood flow evoked by neuronal activity is essential to ensure enough energy supply to the brain. In the neurovascular unit, endothelial cells are ideally placed to regulate key neurovascular functions of the brain. Nevertheless, some outstanding questions remain about their exact role neurovascular coupling (NVC). Here, we...
Conference Paper
Full-text available
Numerous diseases find their origin and their diagnosis in the physiological behavior of vascular networks [10]. In particular, to understand the architecture and growth of a tumor the study of blood flows is crucial. Recently, Ultrasensitive Doppler has enabled 4D ultrasound imaging of tumor micro-vasculature in mice [5]. In this study, we propose...
Preprint
Full-text available
A shift of paradigm is currently underway in biomedical ultrasound thanks to plane and diverging waves for ultrafast imaging. One remaining challenge consists in the correction of phase and amplitude aberrations induced during propagation through complex layers. Unlike conventional line-per-line imaging, ultrafast ultrasound provides for each trans...
Article
Full-text available
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...
Article
Full-text available
Neuroimaging modalities such as MRI and EEG are able to record from the whole brain, but this comes at the price of either limited spatiotemporal resolution or limited sensitivity. Here, we show that functional ultrasound imaging (fUS) of the brain is able to assess local changes in cerebral blood volume during cognitive tasks, with sufficient temp...
Article
For successful brain therapy, transcranial focused ultrasound must compensate for the time shifts induced locally by the skull. The patient-specific phase profile is currently generated by multi-element arrays which, over time, have tended towards increasing element count. We recently introduced a new approach, consisting of a single-element transd...
Preprint
Full-text available
Deep regions of the brain are not easily accessible to investigation at the mesoscale level in awake animals or humans. We have recently developed functional Ultrasound (fUS) imaging fUS imaging technique to uncover deep hemodynamic functional responses. Applying fUS imaging on two awake non-human primates performing a passive fixation task, we rec...
Article
Full-text available
Rapid eye movement sleep (REMS) is a peculiar brain state combining the behavioral components of sleep and the electrophysiological profiles of wake. After decades of research our understanding of REMS still is precluded by the difficulty to observe its spontaneous dynamics and the lack of multimodal recording approaches to build comprehensive data...
Preprint
Full-text available
In recent decades, neuroimaging has played an invaluable role in improving the fundamental understanding of the brain. At the macro scale, neuroimaging modalities such as MRI, EEG, and MEG, exploit a wide field of view to explore the brain as a global network of interacting regions. However, this comes at the price of either limited spatiotemporal...
Presentation
Brain-machine interfaces (BMIs) use neurophysiological signals from the brain to control external devices. Ideally, BMIs have high spatiotemporal resolution, are noninvasive, and portable. Most BMIs rely on neuroelectric methods that are either invasive (e.g. microelectrode arrays) or suffer from poor signal fidelity (e.g. EEG). BMIs based on metab...
Poster
High-density neural interfaces require the ability to observe large-scale patterns of neural activity with high spatiotemporal resolution. Ideally, they should be non-invasive (or minimally invasive) to facilitate their applications in research and potential clinical studies. Current methods to monitor neural activity, including electrophysiology,...
Article
Full-text available
The non-invasive quantification of human tissue fat fraction using easily scalable and accessible imaging technologies is crucial for the diagnosis of many diseases including liver steatosis. Here, we propose a non-invasive quantification of fat content using a highly accessible ultrasonic imaging technology. Ultrasonic echoes backscattered from hu...
Article
4D Ultrafast ultrasound imaging was recently proposed to image and quantify blood flow with high sensitivity in 3D (Provost et al., 2014) as well as anatomical, mechanical or functional information. In 4D Ultrafast imaging, coherent compounding of tilted planes waves emitted by a 2-D matrix array are used to image the medium at high volume rate. 4D...
Article
Dynamic elastography is a virtual palpation tool that aims at investigating the mechanical response of biological soft tissues in vivo. The objective of this study is to develop a finite element model (FEM) with low computational cost for reproducing realistically wave propagation for magnetic resonance elastography in heterogeneous soft tissues. B...
Article
Full-text available
We present herein 3-D Elastic Tensor Imaging (3-D ETI), an ultrasound-based volumetric imaging technique to provide quantitative volumetric mapping of tissue elastic properties in weakly elastic anistropic media. The technique relies on 1) 4-D Ultrafast Shear Wave Elastography (SWE) at very high volume rate (e.g. > 8000 Hz, depending only on the im...
Article
Full-text available
In the last decade, ultrasound imaging has gained new capabilities and produced new insights in the field of neuroscience. The development of new concepts, such as ultrafast ultrasound, has enhanced Doppler sensitivity by orders of magnitude and has paved the way for ultrasonic functional neuroimaging. In this review, we position ultrasound in the...
Chapter
Full-text available
Ultrasensitive Doppler is a recent medical imaging technique enabling high sensitive acquisition of blood flows which can detect small vascular features without contrast agents. Applied to cerebral tomographic imaging of rodents, this method produces very fine vascular 3D maps of the brain at high spatial resolution of 100 μm. These vascular networ...
Chapter
Full-text available
Minimal path approaches for image analysis aim to extract curves minimizing an energy functional. The energy of a path corresponds to its weighted curve length according to a relevant metric function. In this study, we design a binary isotropic metric model with the use of a Hessian-based vascular enhancement filter in order to extract geometrical...
Article
The development of multi-element arrays for better control of the shape of ultrasonic beams has opened the way for focusing through highly aberrating media, such as the human skull. As a result, the use of brain therapy with transcranial-focused ultrasound has rapidly grown. Although effective, such technology is expensive. We propose a disruptive,...