1. Articles from Sébastien Vergnole

    1-16 of 16
    1. Intravascular optical coherence tomography to characterize tissue deformation during angioplasty: preliminary experiments with artery phantoms

      Intravascular optical coherence tomography to characterize tissue deformation during angioplasty: preliminary experiments with artery phantoms

      We explored the potential of intravascular optical coherence tomography (IVOCT) to assess deformation during angioplasty balloon inflation. Using a semi-compliant balloon and artery phantoms, we considered two experimental scenarios. The goal for the first scenario was to investigate if variation in the elasticity of the structure surrounding the balloon could be sensed by IVOCT monitoring. In this scenario, we used three single-layer phantoms with various mechanical properties. Image analysis was performed to extract the inner and outer diameters of the phantoms at various pressures. The goal for the second scenario was twofold. First, we investigated the IVOCT capability to monitor ...

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    2. Optimal signal processing of nonlinearity in swept-source and spectral-domain optical coherence tomography

      Optimal signal processing of nonlinearity in swept-source and spectral-domain optical coherence tomography

      We demonstrate the efficiency of the convolution using an optimized Kaiser–Bessel window to resample nonlinear data in wavenumber for Fourier-domain optical coherence tomography (OCT). We extend our previous experimental demonstration that was performed with a specific swept-source nonlinearity. The method is now applied to swept-source OCT data obtained for various simulated swept-source nonlinearities as well as spectral-domain OCT data obtained from both simulations and experiments. Results show that the new optimized method is the most efficient for handling all the different types of nonlinearities in the wavenumber domain that one can encounter in normal practice. The efficiency of the ...

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    3. Real-time Control of Angioplasty Balloon Inflation Based on Feedback from Intravascular Optical Coherence Tomography: Experimental Validation on an Excised Heart and a Beating Heart Model

      Real-time Control of Angioplasty Balloon Inflation Based on Feedback from Intravascular Optical Coherence Tomography: Experimental Validation on an Excised Heart and a Beating Heart Model

      We report on real-time control of balloon inflation inside porcine arteries. In a first step, experiments were done in a coronary artery of an excised heart. In a second step, experiments were done in a beating heart setup providing conditions very close to in vivo conditions without the complications. A programmable syringe pump was used to inflate a compliant balloon in arteries, while intravascular optical coherence tomography (IVOCT) monitoring was performed. In a feedback loop, IVOCT images were processed to provide the balloon diameter values in real-time to control the pump action in order to achieve a target diameter. In ...

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    4. Real-time Control of Angioplasty Balloon Inflation Based on Feedback from Intravascular Optical Coherence Tomography: Preliminary Study on an Artery Phantom

      Real-time Control of Angioplasty Balloon Inflation Based on Feedback from Intravascular Optical Coherence Tomography: Preliminary Study on an Artery Phantom

      A method is proposed to achieve computerized control of angioplasty balloon inflation, based on feedback from intravascular optical coherence tomography (IVOCT). Controlled balloon inflation could benefit clinical applications, cardiovascular research, and medical device industry. The proposed method was experimentally tested for balloon inflation within an artery phantom. During balloon inflation, luminal contour of the phantom was extracted from IVOCT images in real-time. Luminal diameter was estimated from the obtained contour and was used in a feedback loop. Based on the estimated actual diameter and a target diameter, a computer controlled a programmable syringe pump to deliver or withdraw liquid in ...

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    5. Optical coherence tomography layer thickness characterization of a mock artery during angioplasty balloon deployment

      Optical coherence tomography layer thickness characterization of a mock artery during angioplasty balloon deployment

      Optical coherence tomography (OCT) is used to study the deformation of a mock artery in an angioplasty simulation setup. An OCT probe integrated in a balloon catheter provides intraluminal real-time images during balloon inflation. Swept-source OCT is used for imaging. A 4 mm semi-compliant polyurethane balloon is used for experiments. The balloon is inflated inside a custom-built multi-layer artery phantom. The phantom has three layers to mock artery layers, namely, intima, media and adventitia. Semi-automatic segmentation of phantom layers is performed to provide a detailed assessment of the phantom deformation at various inflation pressures. Characterization of luminal diameter and thickness ...

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    6. Detection of inflating balloon in optical coherence tomography images of a porcine artery in a beating heart experiment

      Detection of inflating balloon in optical coherence tomography images of a porcine artery in a beating heart experiment

      Suboptimal results of angioplasty procedures have been correlated to arterial damage during balloon inflation. We propose to monitor balloon inflation during the angioplasty procedure by detecting the balloon contours with intravascular optical coherence tomography (IVOCT). This will shed more light on the interaction between the balloon and the artery and to assess the artery's mechanical response. An automatic edge detection algorithm is applied for detection of the outer surface of an inflating balloon in a porcine artery in a beating heart experiment. A compliant balloon is inflated to deform the artery. IVOCT monitoring of balloon inflation is performed at ...

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    7. Toward better treatment of clogged arteries

      Toward better treatment of clogged arteries
      Real-time detailed monitoring of angioplasty balloon deformation may lead to improved medical devices to treat hardened artery walls. Intravascular optical coherence tomography (IVOCT) is a catheter-based technique that provides detailed cross-sectional imaging of the artery wall with a resolution of the order of ten micrometers. The clinical relevance of IVOCT has been demonstrated in many studies for the diagnosis and treatment monitoring of atherosclerosis1 (hardening and/or thickening of arteries by deposited plaques of cholesterol and other lipids, inflammatory cells, and calcium deposits). The technology is mature enough to be distributed commercially.2 Images may be acquired during a ‘pullback ...
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    8. Tailoring wavelength sweep for SS-OCT with a programmable picosecond laser

      Tailoring wavelength sweep for SS-OCT with a programmable picosecond laser

      This paper presents a unique and novel picosecond laser source that offers complete tailoring of the wavelength sweep and that benefits swept-source optical coherence tomography (SS-OCT) applications. Along with the advantages of a fiber-based architecture, the source is a fully programmable, electronically controlled actively mode-locked laser capable of rapidly tuning the wavelength and pulse characteristics. Furthermore, several sweep modes and configurations are available which can be defined by range, with linear sweeps in wavelength or k-space, or by arbitrary wavelengths. The source design is discussed and its use in SS-OCT with a prototype using a semiconductor optical amplifier as a ...

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    9. Optical Coherence Tomography Characterization of Balloon Diameter and Wall Thickness

      Optical Coherence Tomography Characterization of Balloon Diameter and Wall Thickness
      (An intravascular optical coherence tomography probe is integrated in a computerized angioplasty balloon deployment system. The resulting setup can be useful in many applications. In this paper, based on the acquired intraluminal images, we achieve a detailed assessment of the diameter and wall thickness of the inflated balloon at different pressures. Such analysis is helpful in testing the balloon quality, in assessing deformation model, or in validating new balloon designs.
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    10. Intravascular optical coherence tomography on a beating heart model

      Intravascular optical coherence tomography on a beating heart model
      The advantages and limitations of using a beating heart model in the development of intravascular optical coherence tomography are discussed. The model fills the gap between bench experiments, performed on phantoms and excised arteries, and whole animal in-vivo preparations. The beating heart model is stable for many hours, allowing for extended measurement times and multiple imaging sessions under in-vivo conditions without the complications of maintaining whole-animal preparation. The perfusate supplying the heart with nutrients can be switched between light scattering blood to a nonscattering perfusate to allow the optical system to be optimized without the need of an efficient blood ...
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    11. Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester

      Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester
      Hamed Azarnoush, Sebastien Vergnole, Rafik Bourezak, Benoit Boulet, and Guy Lamouche We present an innovative integration of an intravascular optical coherence tomography probe into a computerized balloon deployment system to monitor the balloon inflation process. The high-resolution intraluminal imaging of the balloon provides a detailed assessment of the balloon quality and, conse ... [Rev. Sci. Instrum. 81, 083101 (2010)] published Mon Aug 2, 2010.
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    12. Experimental validation of an optimized signal processing method to handle non-linearity in swept-source optical coherence tomography

      Experimental validation of an optimized signal processing method to handle non-linearity in swept-source optical coherence tomography
      We evaluate various signal processing methods to handle the non-linearity in wavenumber space exhibited by most laser sources for swept-source optical coherence tomography. The following methods are compared for the same set of experimental data: non-uniform discrete Fourier transforms with Vandermonde matrix or with Lomb periodogram, resampling with linear interpolation or spline interpolation prior to fast-Fourier transform (FFT), and resampling with convolution prior to FFT. By selecting an optimized Kaiser-Bessel window to perform the convolution, we show that convolution followed by FFT is the most efficient method. It allows small fractional oversampling factor between 1 and 2, thus a minimal ...
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    13. Signal processing with unequally spaced data in Fourier-domain optical coherence tomography

      Signal processing with unequally spaced data in Fourier-domain optical coherence tomography
      Different algorithms for performing Fourier transforms with unequally sampled data in wavenumber space for Fourier-domain optical coherence tomography are considered. The efficiency of these algorithms is evaluated from point-spread functions obtained with a swept-source optical coherence tomography system and from computational time. Images of a 4-layer phantom processed with these different algorithms are compared. We show that convolving the data with an optimized Kaiser-Bessel window allowing a small oversampling factor before computing the fast Fourier transform provides the optimal trade-off between image quality and computational time.
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    14. Artifact removal in FD-OCT with a B-M mode scanning technique: condition on the transverse step

      and One of the main drawbacks of Fourier-domain optical coherence tomography is its inability to differentiate between positive and negative locations relative to the zero-delay position. In the recently proposed B-M mode scanning technique, these artifacts are removed by introducing a transverse modula ... [Proc. SPIE 7168, 71682M (2009)] published Fri Feb 20, 2009.
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    15. Artifact removal in Fourier-domain optical coherence tomography with a piezoelectric fiber stretcher

      Sébastien Vergnole, Guy Lamouche, Marc L. Dufour. We describe an artifact removal setup swept-source optical coherence tomography (OCT) system that enables high-speed full-range imaging. We implement a piezoelectric fiber stretcher to generate a periodic phase shift between successive A-scans, thus introducing a transverse modulation. The depth ... [Opt. Lett. 33, 732-734 (2008)]
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    16. Artifact removal in Fourier-domain OCT with a rotating probe

      Sebastien Vergnole, Guy Lamouche, Marc L. Dufour et al. This paper reports the study of a Swept Source Optical Coherence Tomography (SS-OCT) setup to remove depth degeneracy for measurements performed with a rotating probe. One of the main drawbacks of SS-OCT is its inability to differentiate positive and negative depths. Some setups have already been pr ... [Proc. SPIE Int. Soc. Opt. Eng. 6851, 68510G (2008)] published Tue Feb 5, 2008.
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    1-16 of 16
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  2. Topics in the News

    1. (15 articles) National Research Council Canada
    2. (1 articles) University of Waterloo
    3. (1 articles) University of Manitoba
    4. (1 articles) Genia Photonics
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    Signal processing with unequally spaced data in Fourier-domain optical coherence tomography Experimental validation of an optimized signal processing method to handle non-linearity in swept-source optical coherence tomography Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester Intravascular optical coherence tomography on a beating heart model Toward better treatment of clogged arteries Tailoring wavelength sweep for SS-OCT with a programmable picosecond laser Real-time Control of Angioplasty Balloon Inflation Based on Feedback from Intravascular Optical Coherence Tomography: Preliminary Study on an Artery Phantom Real-time Control of Angioplasty Balloon Inflation Based on Feedback from Intravascular Optical Coherence Tomography: Experimental Validation on an Excised Heart and a Beating Heart Model The Structural and Comparative Analysis of Intravitreal Dexamethasone Implant (Ozurdex) and Anti-VEGF Injection in Branched Retinal Vein Occlusion Patients by Optical Coherence Tomography Angiography Images Quantitation Vascular Responses to First-Generation Sirolimus-Eluting Stents and Bare-Metal Stents Beyond 10 Years Ocular Parameters Evaluation in Relation to the Refractive Error using Optical Coherence Topography Micro Optical Coherence Tomography for Coronary Imaging