Thu-Mai Nguyen

Thu-Mai Nguyen
Physics for Medicine Paris, France (Inserm/ESPCI Paris/CNRS/PSL Research University) · Technology Research Accelerator for Biomedical Ultrasound (Inserm A.R.T.)

PhD

About

41
Publications
7,130
Reads
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845
Citations
Citations since 2017
4 Research Items
565 Citations
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
Additional affiliations
October 2014 - present
Institut Langevin Ondes et Images, Paris, France
Position
  • PostDoc Position
Description
  • Optical coherence tomography for ophthalmic applications
January 2013 - September 2014
University of Washington Seattle
Position
  • PostDoc Position
Description
  • Optical coherence elastography, photo-acoustic imaging
September 2010 - June 2012
Paris Diderot University
Position
  • Research Assistant
Description
  • Optics and mechanics, 64 hours/year.
Education
September 2009 - December 2012
Paris Diderot University
Field of study
  • Physical acoustics
September 2008 - June 2009
Paris Diderot University
Field of study
  • Physical acoustics
September 2005 - June 2009
École Supérieure de Physique et de Chimie Industrielles
Field of study
  • Physics, Chemistry, Biology

Publications

Publications (41)
Article
Full-text available
Corneal scarring associated with various corneal conditions is a leading cause of blindness worldwide. The present study aimed to test the hypothesis that corneal stromal stem cells have a therapeutic effect and are able to restore the extracellular matrix organization and corneal transparency in vivo. We first developed a mouse model of corneal st...
Article
Full-text available
We uncover the significance of a previously unappreciated structural feature in corneal stroma, important to its biomechanics. Vogt striae are a known clinical indicator of keratoconus, and consist of dark, vertical lines crossing the corneal depth. However we detected stromal striae in most corneas, not only keratoconus. We observed striae with mu...
Article
Optical coherence tomography (OCT) can map the stiffness of biological tissue by imaging mechanical perturbations (shear waves) propagating in the tissue. Most shear wave elastography (SWE) techniques rely on active shear sources to generate controlled displacements that are tracked at ultrafast imaging rates. Here, we propose a noise-correlation a...
Article
Full-text available
Optical coherence tomography (OCT)-based elasticity imaging can map soft tissue elasticity based on speckle-tracking of elastic wave propagation using highly sensitive phase measurements of OCT signals. Using a fixed elastic wave source and moving detection, current imaging sequences have difficulty in reconstructing tissue elasticity within speckl...
Conference Paper
Phase-sensitive optical coherence tomography (PhS-OCT) can be utilized for quantitative shear-wave elastography using speckle tracking. However, current approaches cannot directly reconstruct elastic properties in speckle-less or speckle-free regions, for example within the crystalline lens in ophthalmology. Investigating the elasticity of the crys...
Conference Paper
To integrate real-time photoacoustics (PA) into ultrasound (US) scanners and accelerate clinical translation of combined PAUS imaging, we previously developed a system using a portable, low-cost, low pulse energy, high-repetition rate laser (~1kHz) with a 1D galvo-mirror for rapid laser beam scanning over the imaging area. However, the frame rate a...
Article
Magnetomotive photoacoustic/ultrasound imaging has shown superior specificity in visualizing targeted objects at cellular and molecular levels. By detecting magnet-induced displacements, magnetic-particle-targeted objects can be differentiated from background signals insensitive to the magnetic field. Unfortunately, background physiologic motion in...
Article
Ultrasound-guided photoacoustic imaging has shown great potential for many clinical applications including vascular visualization, detection of nanoprobes sensing molecular profiles, and guidance of interventional procedures. However, bulky and costly lasers are usually required to provide sufficient pulse energies for deep imaging. The low pulse r...
Article
Full-text available
Tissue stiffness can be measured from the propagation speed of shear waves. Acoustic radiation force (ARF) can generate shear waves by focusing ultrasound in tissue for ∼100 μs. Safety considerations and electronics abilities limit ultrasound pressures. We previously presented shear wave elastography combining ARF and phase-sensitive optical cohere...
Article
Photoacoustic imaging has emerged as a highly promising tool to visualize molecular events with deep tissue penetration. Like most other modalities, however, image contrast under in vivo conditions is far from optimal due to background signals from tissue. Using iron oxide-gold core-shell nanoparticles, we have previously demonstrated the concept o...
Article
Full-text available
Because of depth-dependent light attenuation, bulky, low-repetition-rate lasers are usually used in most photoacoustic (PA) systems to provide sufficient pulse energies to image at depth within the body. However, integrating these lasers with real-time clinical ultrasound (US) scanners has been problematic because of their size and cost. In this pa...
Article
Full-text available
Photoacoustic (PA) imaging using exogenous agents can be limited by degraded specificity due to strong background signals. This paper introduces a technique called sono-photoacoustics (SPA) applied to perfluorohexane nanodroplets coated with gold nanospheres. Pulsed laser and ultrasound (US) excitations are applied simultaneously to the contrast ag...
Article
Full-text available
Investigating the elasticity of ocular tissue (cornea and intraocular lens) could help the understanding and management of pathologies related to biomechanical deficiency. In previous studies, we introduced a setup based on optical coherence tomography for shear wave elastography (SWE) with high resolution and high sensitivity. SWE determines tissu...
Article
Full-text available
Dynamic elastography using radiation force requires that an ultrasound field be focused during hundreds of microseconds at a pressure of several megapascals. Here, we address the importance of the focal geometry. Although there is usually no control of the elevational focal width in generating a tissue mechanical response, we propose a tunable appr...
Article
Full-text available
Purpose: This work proposes shear wave elastography to quantify the elastic anisotropy of the cornea. Methods: Experiments were conducted on enucleated porcine eyeballs and anesthetized swine. We used the supersonic shear wave imaging (SSI) method implemented on a dedicated 15-MHz rotating linear ultrasound array. This setup allows determining t...
Article
In this study, our collaborative research group explored the possibility of incorporating ultrasound elastography technology with a microfluidic device that is designed to prepare fine needle core biopsies (CBs; L=0.5-2.0 cm, D=0.4-1.2 mm) for pancreatic cancer diagnosis. For the first time, elastographic techniques were employed to measure shear w...
Conference Paper
Full-text available
We combined phase-sensitive optical coherence tomography (PhS-OCT) and acoustic radiation force (ARF) to develop a shear wave elastography (SWE) method that could be used for ophthalmic applications. SWE measures tissue stiffness from the speed of shear waves propagating through tissue. Assessing the elastic properties of the cornea and the intraoc...
Conference Paper
Ultrasound (US) needle tracking with a real-time, portable imaging system is common for biopsies and therapeutic injections. However, proper US probe-needle orientation is required or tracking precision is lost because of poor US contrast and additional artifacts. In contrast, the strong photoacoustic (PA) signal from a needle is relatively indepen...
Conference Paper
Assessing the biomechanical properties of the cornea can provide clinically valuable information in addition to structural images for better management of pathologies (e.g. glaucoma) or refractive surgeries. OCT provides a micron scale and high sensitivity that are ideal for ophthalmic applications. We propose a shear wave elastography (SWE) method...
Conference Paper
Full-text available
Due to the high scattering coefficient of tissue over the wavelength range used for photoacoustic (PA) imaging, most studies employ bulky, low repetition rate lasers to provide sufficient pulse energies at depth to image within the body. The size and cost of these lasers has impeded integration of photoacoustics into conventional, routinely-used ul...
Article
Full-text available
Optical coherence tomography (OCT) provides high spatial resolution and sensitivity that are ideal for imaging the cornea and lens. Quantifying the biomechanical properties of these tissues could add clinically valuable information. Thus, we propose a dynamic elastography method combining OCT detection and a mechanical actuator to map the shear mod...
Article
Full-text available
We report on the use of phase-sensitive optical coherence tomography (PhS-OCT) to detect and track temporal and spatial shear wave propagation within tissue, induced by ultrasound radiation force. Kilohertz-range shear waves are remotely generated in samples using focused ultrasound emission and their propagation is tracked using PhS-OCT. Cross-sec...
Article
Full-text available
Purpose: To assess corneal stiffening with supersonic shear wave imaging (SSI) technology in an experimental model of iontophoresis-assisted transepithelial corneal collagen cross-linking (I-CXL). Methods: Six rabbits underwent full, central I-CXL in one eye. The contralateral eye served as control. In vivo iontophoresis was used for 10 minutes...
Article
Full-text available
Shear wave elastography measures the stiffness of soft tissues from the speed of propagating shear waves induced in tissue. Optical coherence tomography (OCT) is a promising detection modality given its high sensitivity and spatial resolution, making it suitable for elastic characterization of skin, peripheral vasculature or ocular tissues. For cli...
Article
Full-text available
Assessing the biomechanical properties of soft tissue provides clinically valuable information to supplement conventional structural imaging. In the previous studies, we introduced a dynamic elastography technique based on phase-sensitive optical coherence tomography (PhS-OCT) to characterize submillimetric structures such as skin layers or ocular...
Article
Full-text available
We propose an integrated method combining low-frequency mechanics with optical imaging to map the shear modulus within the biological tissue. Induced shear wave propagating in tissue is tracked in space and time using phase-sensitive optical coherence tomography (PhS-OCT). Local estimates of the shear-wave speed obtained from tracking results can i...
Article
Full-text available
Elasticity maps of tissue have proved to be particularly useful in providing complementary contrast to ultrasonic imaging, e.g., for cancer diagnosis at the millimeter scale. Optical coherence tomography (OCT) offers an endogenous contrast based on singly backscattered optical waves. Adding complementary contrast to OCT images by recording elastici...
Article
This thesis presents the implementation of a high-resolution quantitative elastography technique for the assessment of the biomechanical properties of the cornea and the skin. For this purpose, the Supersonic Shear wave Imaging (SSI) method has been upgraded to high-frequency ultrasound (up to 20 MHz). The SSI elastography consists in retrieving st...
Article
Full-text available
Purpose: Keratoconus disease or post-LASIK corneal ectasia are increasingly treated using UV-A/riboflavin-induced corneal collagen cross-linking (CXL). However, this treatment suffers from a lack of techniques to provide an assessment in real-time of the CXL effects. Here, we investigated the potential interest of corneal elasticity as a biomarker...
Article
Full-text available
Elasticity estimation of thin-layered soft tissues has gained increasing interest propelled by medical applications like skin, corneal, or arterial wall shear modulus assessment. In this work, the authors propose one-dimensional transient elastography (1DTE) for the shear modulus assessment of thin-layered soft tissue. Experiments on three phantoms...
Article
Full-text available
In elastography, quantitative imaging of soft tissue elastic properties is provided by local shear wave speed estimation. Shear wave imaging in a homogeneous medium thicker than the shear wavelength is eased by a simple relationship between shear wave speed and local shear modulus. In thin layered organs, the shear wave is guided and thus undergoes...
Conference Paper
The cornea is mainly composed of type I collagen fibrils. The organization of those fibers ensures the cornea transparency and determines its biomechanical properties. Understanding the biomechanics of the cornea has become a crucial issue in ophthalmology to predict the cornea response to refractive surgery procedures and to avoid post-treatment c...
Article
Full-text available
Quantitative measurements of cornea and skin biomechanical properties have many applications in medicine. In ophthalmology, it could lead to a better diagnosis of pathologies or monitoring of treatments. In dermatology, it could help the skin lesions removal monitoring. In the framework of Supersonic Shear Imaging (SSI), these organs are characteri...
Conference Paper
Supersonic Shear Imaging (SSI) is a quantitative stiffness imaging technique based on the combination of a radiation force induced in tissue by an ultrasonic beam and ultrafast ultrasound imaging sequence (up to more than 10000 frames per second) catching in real time the propagation of the resulting shear waves. Local shear wave speed is estimated...

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