May 3, 2016 admin

Sophie Caujolle

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Project title, ESR3: Ultra broadband system for histology and submicron resolution of cells

Aiming to combine both interest in medical science and optics by working on a non-invasive imaging system with micron resolution.

Current projects and research areas

  • Ultra-broadband Optical Coherence Tomography for submicron resolution
  • Phase sensitivity OCT
  • OCT Angiography
  • Fourier-domain, and master-slave OCT configurations

 

Motivation

In the early nineties, a new optical method based on low-coherence interferometry called Optical Coherence Tomography (OCT) was developed. 
This non-invasive imaging method has been widespread in ophthalmology over the past decades thanks to its ability to visualize ocular structures at high resolution in lateral and axial direction.

To improve even better axial resolution, the use of ultra-broadband source is needed such as a supercontinuum source from NKT Photonics. Although this system is able to provide good visual structural data, doctors want more by asking to add different kind of information. Therefore, there is a strong pull for OCT to move from structural imaging to functional imaging to add additional information to the morphological information, like polarization sensitive OCT, spectroscopic OCT, elastographic OCT and so forth.
Age-related macular degeneration, glaucoma and diabetic retinopathy are the three main causes for visual field loss and blindness. These diseases have an impact on blood vessels such as the presence of choroidal neovacularization, a reduction or complication in retinal blood flow. Currently, the gold standard for imaging the vasculature network is Fluorescein Angiography (FA) and Indocyanine Green Angiography (IGA). However, both are invasive and require intraveneous dye injections.
OCT angiography is a solution providing superficial and deep vascular plexuses. This method solves the previous mentioned issues from FA and IGA. In this project, different methods from phase sentivity OCT to speckle variance OCT are investigated.

 

Professional Experience

  • 2016 – present: Canterbury, UK
    [PhD] Researcher – University of Kent
  • 2014 – 2016: Birkerod, Denmark
    [PhD] Researcher – NKT Photonics A/S
  • April – September 2014: Vienna, Austria
    [Master thesis] Setting up a Thermal Light Source for Spectral Domain Optical Coherence Tomography – Center of Medical Physics and Biomedical Engineering
  • November – March 2014: Jena, Germany
    [Research Labwork Optic] Below 50 nm BaTiO3 core-shell nanoparticles for biological application – Institute for Applied Physics

 

Education

  • 2013 – 2014: Friedrich-Schiller-Universität Jena
    Master’s degree, Photonic – Germany
  • 2011 – 2014 : ENSSAT
    Master’s degree, Optronics Engineering – France
  • 2008 – 2011: Lycée les Eucalyptus
    Bachelor’s degree in Physics – France

PUBLICATIONS

Peer reviewed papers

Biomedical Optics Express (Gold open access),  Vol. 8, Issue 11, pp. 5139-5150, (2017) doi.org/10.1364/BOE.8.005139

  • Title: Speckle Variance OCT for Depth resolved assessment of the viability of bovine embryos
  • Authors: Sophie Caujolle, Ramona Cernat, Giuseppe Silvestri, Manuel Marques, Adrian Bradu, Thomas Feuchter, Gary Robinson, Darran Griffin, Adrian Podoleanu
  • Abstract: The morphology of embryos produced by in vitro fertilization (IVF) is commonly used to estimate their viability. However, imaging by standard microscopy is subjective and unable to assess the embryo on a cellular scale after compaction. Optical Coherence Tomography is an imaging technique that can produce a depth-resolved profile of a sample and can be coupled with Speckle Variance (SV) to detect motion on a micron scale. In this study, day 7 post-IVF bovine embryos were observed either short-term (10 minutes) or long-term (over 18 hours) and analyzed by swept source OCT and SV to resolve their depth profile and characterize micron-scale movements potentially associated with viability. The percentage of en face images showing movement at any given time was calculated as a method to detect the vital status of the embryo. This method could be used to measure the levels of damage sustained by an embryo, for example after cryopreservation, in a rapid and non-invasive way.

List of peer review conferences:

  1. Danish Optical Society annual meeting 2014 (no proceeding), Organiser: Danish Optical Society, Venue: DTU Risø, 13 – 14. November 2014, Website: http://dops.dk/
  • Type: Poster
    • Title: Building up a thermal light source for spectral domain optical coherence tomography (OCT)
    • Authors: Sophie Caujolle, René Werkmeister, Léopold Schmetterer
      With the use of computers in everyday life, the number of patients affected by a dry eye syndrome increases. The conventional method of diagnosis is invasive that’s why the idea to image the tear film structure which is directly in relation to this disease with an OCT system could be enticing. For this reason, we need to improve the resolution and the solution mentioned here is to use a light source with a large bandwidth as a thermal bulb. We have two principals’ goals in this thesis. One, the most challenging is to find a compromise between the coherence length and the power. Indeed, to have a correct spatial coherence, we must to reduce the size of the filament but the power greatly decreases. For that, we compare three bulbs and some optical layouts to optimize. The second is to build the interferometer in a large range (700-1000 nm) and to get components which could be well suited without too many optical problems such as aberrations or dispersion.

 

  1. Danish Opening Ceremony of the International Year of Light (no proceeding), Organiser: Danish Physics Society, Venue: DTU Lyngby, 22 – 23 January 2015
  • Type: Poster
    • Title: Building up a thermal light source for spectral domain optical coherence tomography (OCT)
    • Authors: Sophie Caujolle, René Werkmeister, Léopold Schmetterer
      With the use of computers in everyday life, the number of patients affected by a dry eye syndrome increases. The conventional method of diagnosis is invasive that’s why the idea to image the tear film structure which is directly in relation to this disease with an OCT system could be enticing. For this reason, we need to improve the resolution and the solution mentioned here is to use a light source with a large bandwidth as a thermal bulb. We have two principals’ goals in this thesis. One, the most challenging is to find a compromise between the coherence length and the power. Indeed, to have a correct spatial coherence, we must to reduce the size of the filament but the power greatly decreases. For that, we compare three bulbs and some optical layouts to optimize. The second is to build the interferometer in a large range (700-1000 nm) and to get components which could be well suited without too many optical problems such as aberrations or dispersion.

 

  1. Danish Optical Society annual meeting 2015 (no proceeding), Organiser: Danish Optical society, Venue: Odense University, 19 – 20. November 2015, Website: http://dops.dk/ Poster
    • Title: Split-Spectrum Amplitude Decorrelation Angiography using an ultra-broadband source
    • Authors: Sophie Caujolle, Felix Fleischhauer, Thomas Feuchter, Lasse Leick and Adrian Gh. Podoleanu
    • Abstract: Age-related macular degeneration, glaucoma and diabetic retinopathy are the three main causes for visual field loss and blindness. These diseases have an impact on blood vessels such as the presence of choroidal neovacularization and a reduction or complication in retinal blood flow. Optical Coherence Tomography (OCT) is an optical method based on low-coherence interferometry. This non-invasive imaging method allows visualizing of ocular structures at high resolution in lateral and axial direction. There is a strong pull for OCT to move from structural imaging to functional imaging to add additional information to the morphological information, like polarization sensitive OCT, spectroscopic OCT or elastographic OCT. OCT angiography is one of the options by providing superficial and deep vascular plexuses.. One of the used algorithms in OCT angiography to enhance the vessel network is Split-Spectrum Amplitude Decorrelation Angiography (SSADA). This process uses two concepts: the split-spectrum method and the calculation of the amplitude decorrelation. The first technique divides the measured spectrum in spectral bands to reduce the sensitivity of axial fluctuations by averaging over the number of splits. The second step calculates the percentage of likeness between two successive measurements at the same lateral position. Blood cells are randomly located in the vessels over the flow stream. This induces that the scattering signal varies over the time. By calculating the decorrelation between two A-scans, moving signals will be extracted.  An OCT setup with a spectral range from 650 to 950 nm using an ultra-broadband source from NKT Photonics is employed with SSADA. The improvement of using a supercontinuum source is to have the possibility to split the spectrum and keep a reasonable axial resolution or to increase the number of splits. The system is tested with a piezoelectric motor moving in axial direction. The results show that for a stationary sample the two consecutive measurements are 80% similar whereas the correlation drops to 45% in the case of a moving sample.
  1. Photonics West 2017
  • Type: Poster, Posters I: Technology and Image Processing, Paper 10053-86, Sunday 29 January 2017, 5:30 PM – 7:30 PM
  • Title: Phase-sensitive, complex-domain master-slave interferometry
  • Authors: Manuel J. Marques, Sophie Caujolle, Sylvain Rivet, Adrian Bradu and Adrian Gh. Podoleanu
  • Abstract: In this communication we report on the added functionality to optical coherence tomography (OCT) systems, enabled by complex-domain master-slave interferometry (cMSI)1: that of phase-sensitive measurements. Phase-sensitive optical coherence tomography (PhS-OCT) can be employed to characterize the flow properties of a biological tissue by using methods such as phase variance or Doppler OCT2, and also to measure additional polarimetric properties of a sample3. The cMSI method is an alternative to the conventional Fourier transform based method, however in our previous reports on MSI the phase had been discarded. This is the first report where we investigate the phase-sensitive capabilities of the cMSI method. To this goal, we perform measurements on a flow phantom and carry out flow measurements for different flow rates. We compare the results obtained by both techniques, the conventional FT based spectral interferometry (applied to resampled data sets) and cMSI. The quality of the phase information retrieved using the cMSI method compares favorably to that obtained using the FT based conventional spectral domain interferometry.
  1. European Conferences on Biomedical Optics, 2017, Munich, Germany Proceedings Volume 10416, Optical Coherence Imaging Techniques and Imaging in Scattering Media II;1041608 (2017); doi: 10.1117/12.2289701.
  • Type: Oral presentation
    • Title: Comparison between a supercontinuum source and a titanium sapphire laser in achieving ultrahigh resolution spectral domain optical coherence tomography (SD-OCT)
    • Authors: Sophie Caujolle, Unterhuber, Thomas Feuchter, Adrian Gh. Podoleanu and René Werkmeister
    • Abstract: Corneal B-scan images and signa-to-noise ratio measurements using ultra-high resolution Spectral Domain Optical Coherence Tomography (SD-OCT) are reported. A comparison of results is obtained using a Ti:Sa laser and a supercontinuum optical source, is performed. Beside some differences in the SNR, the images are strikingly similar.

6. 2nd Canterbury Conference on OCT, SPIE 10591, 2nd Canterbury Conference on OCT with Emphasis on Broadband Optical Sources, 1059108 (5 March 2018), 6-8 Sept 2017; doi: 10.1117/12.2282912; https://doi.org/10.1117/12.2282912

  • Type: Oral presentation
  • Prize: Third place on Best presentation award
  • Title: Assessing Embryo Development using Swept Source Optical Coherence Tomography
  • Authors: Sophie Caujolle, Ramona Cernat, Giuseppe Silvestri, Manuel J. Marques, Adrian Bradu, Thomas Feuchter, Gary Robinson, Darran Griffin and Adrian Podoleanu
  • Abstract: A detailed assessment of embryo development would assist biologists with selecting the most suitable embryos for transfer leading to higher pregnancy rates. Currently, only low resolution microscopy is employed to perform this assessment. Although this method delivers some information on the embryo surface morphology, no specific details are shown related to its inner structure. Using Swept Source Optical Coherence Tomography (SS-OCT), images of cow embryos from day 7 after fertilization were collected from different depths. The dynamic changes inside the embryos were examined, in detail and in real-time from several depths. To prove our ability to characterize the morphology, a single embryo was imaged over 26 hours. The embryo was deprived of its life support environment, leading to its death. Over this period, clear morphological changes were observed.

 

List of further attended conference

  1. Marie Skłodowska-Curie Action ESOF Satellite conference, Website: https://www.h2020.cz/files/perutkova/MSCA-ESOF-programme-July-2016.pdf,  28 – 29 Juny 2016
  • Title: UBAPHODESA – Ultrawide Bandwidth Photonics Devices, Sources and Applications,
  • Authors: Magalie Bondu, Sophie Caujolle, Felix Fleischhauer, Michael Maria, Lasse Leick, Thomas Feuchter and Adrian Podoleanu
  1. Postgraduate Festival, University of Kent, UK, 05.2017
    • Title: Embryo Evolution by Swept Source Optical Coherence Tomography
    • Authors: Sophie Caujolle, Ramona Cernat, Giuseppe Silvestri, Manuel J. Marques, Adrian Bradu, Thomas Feuchter, Gary Robinson, Darran Griffin and Adrian Podoleanu
    • Abstract: A better understanding of evolution of embryos would help biologist to create a more suitable environment for it reintroduction and success of the insemination. In our study, cow embryo from day 7 and 8 after fertilization, were used. To access to it development, for now, just the use of a microscope is possible. However, this type of image just gives an overall information of the embryo morphology and it is complicated to have detail for each layer of the embryo. Using a swept source optical coherence tomography (SS-OCT), images from different layer called enface images have been acquired and make possible to have a close look on it evolution in real time. To complete our study, a moving map is created which highlights the changing parts by calculating speckle variance between two successive enface images of 1 minute delayed. To prove our ability to characterize the morphology and motion of the sample, a single embryo have been imaged over 26hours (until it died). Over this period, changing parts have been identified in each layers and clear morphological modification can be observed.The embryo died after 18 hours but it is actually important to note that some superficial layers had been already static since 2 hours. The embryo was kept to room temperature so in a stressful environment and leaded to it dead but in the future, it could be considered to let it in a suitable one and access to a complete characterization from fertilization to prenatal development of an embryo by SS-OCT.
  1. Maximise Your Research Impact, University of Kent, UK, 17th May 2017, Woolf College
    • Title: Embryo Evolution by Swept Source Optical Coherence Tomography
    • Authors: Sophie Caujolle, Ramona Cernat, Giuseppe Silvestri, Manuel J. Marques, Adrian Bradu, Thomas Feuchter, Gary Robinson, Darran Griffin and Adrian Podoleanu 
  1. EPSRC Image Guided Therapies Network+ meeting, 7 July 2017, Imperial College London (UK), Poster presentation
    • Title: Embryo Evolution by Swept Source Optical Coherence Tomography
    • Authors: Sophie Caujolle, Ramona Cernat, Giuseppe Silvestri, Manuel J. Marques, Adrian Bradu, Thomas Feuchter, Gary Robinson, Darran Griffin and Adrian Podoleanu