1. Articles from Alexandre Castonguay

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    1. Imaging whole mouse brains with a dual resolution serial swept-source optical coherence tomography scanner

      Imaging whole mouse brains with a dual resolution serial swept-source optical coherence tomography scanner

      High resolution imaging of whole rodent brains using serial OCT scanners is a promising method to investigate microstructural changes in tissue related to the evolution of neuropathologies. Although micron to sub-micron sampling resolution can be obtained by using high numerical aperture objectives and dynamic focusing, such an imaging system is not adapted to whole brain imaging. This is due to the large amount of data it generates and the significant computational resources required for reconstructing such volumes. To address this limitation, a dual resolution serial OCT scanner was developed. The optical setup consists in a swept-source OCT made of two ...

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    2. Comparing three-dimensional serial optical coherence tomography histology to MRI imaging in the entire mouse brain

      Comparing three-dimensional serial optical coherence tomography histology to MRI imaging in the entire mouse brain

      An automated serial histology setup combining optical coherence tomography (OCT) imaging with vibratome sectioning was used to image eight wild type mouse brains. The datasets resulted in thousands of volumetric tiles resolved at a voxel size of ( 4.9 × 4.9 × 6.5 ) μ m 3 (4.9×4.9×6.5)  μm3 stitched back together to give a three-dimensional map of the brain from which a template OCT brain was obtained. To assess deformation caused by tissue sectioning, reconstruction algorithms, and fixation, OCT datasets were compared to both in vivo and ex vivo magnetic resonance imaging (MRI) imaging. The OCT ...

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    3. Serial optical coherence scanning reveals an association between cardiac function and the heart architecture in the aging rodent heart

      Serial optical coherence scanning reveals an association between cardiac function and the heart architecture in the aging rodent heart

      Normal aging is accompanied by structural changes in the heart architecture. To explore this remodeling, we used a serial optical coherence tomography scanner to image entire mouse hearts at micron scale resolution. Ex vivo hearts of 7 young (4 months) and 5 old (24 months) C57BL/6 mice were acquired with the imaging platform. OCT of the myocardium revealed myofiber orientation changing linearly from the endocardium to the epicardium. In old mice, this rate of change was lower when compared to young mice while the average volume of old mice hearts was significantly larger (p<0.05). Myocardial wall thickening ...

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    4. Whole mouse brain imaging using optical coherence tomography: reconstruction, normalization, segmentation, and comparison with diffusion MRI

      Whole mouse brain imaging using optical coherence tomography: reconstruction, normalization, segmentation, and comparison with diffusion MRI

      An automated massive histology setup combined with an optical coherence tomography (OCT) microscope was used to image a total of n = 5 n=5 whole mouse brains. Each acquisition generated a dataset of thousands of OCT volumetric tiles at a sampling resolution of 4.9 × 4.9 × 6.5    μ m 4.9×4.9×6.5  μm . This paper describes techniques for reconstruction and segmentation of the sliced brains. In addition to the measured OCT optical reflectivity, a single scattering photon model was used to compute the attenuation coefficients within each tissue slice. Average mouse brain templates were generated for ...

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    5. White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains

      White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains

      A whole rodent brain was imaged using an automated massive histology setup and an Optical Coherence Tomography (OCT) microscope. Thousands of OCT volumetric tiles were acquired, each covering a size of about 2.5x2.5x0.8 mm3 with a sampling resolution of 4.9x4.9x6.5 microns. This paper shows the techniques for reconstruction, attenuation compensation and segmentation of the sliced brains. The tile positions within the mosaic were evaluated using a displacement model of the motorized stage and pairwise coregistration. Volume blending was then performed by solving the 3D Laplace equation, and consecutive slices were assembled using the cross-correlation ...

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    6. Validating Intravascular Imaging with Serial Optical Coherence Tomography and Confocal Fluorescence Microscopy

      Validating Intravascular Imaging with Serial Optical Coherence Tomography and Confocal Fluorescence Microscopy

      Atherosclerotic cardiovascular diseases are characterized by the formation of a plaque in the arterial wall. Intravascular ultrasound (IVUS) provides high-resolution images allowing delineation of atherosclerotic plaques. When combined with near infrared fluorescence (NIRF), the plaque can also be studied at a molecular level with a large variety of biomarkers. In this work, we present a system enabling automated volumetric histology imaging of excised aortas that can spatially correlate results with combined IVUS/NIRF imaging of lipid-rich atheroma in cholesterol-fed rabbits. Pullbacks in the rabbit aortas were performed with a dual modality IVUS/NIRF catheter developed by our group. Ex vivo ...

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    7. Investigating the correlation between white matter and microvasculature changes in aging using large scale optical coherence tomography and confocal fluorescence imaging combined with tissue sectioning

      Investigating the correlation between white matter and microvasculature changes in aging using large scale optical coherence tomography and confocal fluorescence imaging combined with tissue sectioning

      Here, we present a serial OCT/confocal scanner for histological study of the mouse brain. Three axis linear stages combined with a sectioning vibratome allows to cut thru the entire biological tissue and to image every section at a microscopic resolution. After acquisition, each OCT volume and confocal image is re-stitched with adjacent acquisitions to obtain a reconstructed, digital volume of the imaged tissue. This imaging platform was used to investigate correlations between white matter and microvasculature changes in aging mice. Three age groups were used in this study (4, 12, 24 months). At sacrifice, mice were transcardially perfused with ...

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    8. Ex-vivo multi-modal microscopy of healthy skin

      Ex-vivo multi-modal microscopy of healthy skin

      The thorough characterization of skin samples is a critical step in investigating dermatological diseases. The combination of depth-sensitive anatomical imaging with molecular imaging has the potential to provide vast information about the skin. In this proof-of-concept work we present high-resolution mosaic images of skin biopsies using Optical Coherence Tomography (OCT) manually co-registered with standard microscopy, bi-dimensional Raman spectral mapping and fluorescence imaging. A human breast skin sample, embedded in paraffin, was imaged with a swept-source OCT system at 1310 nm. Individual OCT volumes were acquired in fully automated fashion in order to obtain a large field-of-view at high resolution (~10 ...

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    1-8 of 8
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  2. Topics in the News

    1. (8 articles) Polytechnique Montreal
    2. (8 articles) Frédéric Lesage
    3. (1 articles) University of Montreal
    4. (1 articles) National Research Council Canada
    5. (1 articles) Samsung
    6. (1 articles) Johns Hopkins University
    7. (1 articles) National Institutes of Health
    8. (1 articles) Sungkyunkwan University
    9. (1 articles) University of São Paulo
    10. (1 articles) Massachusetts Institute of Technology
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    12. (1 articles) Gong Je Seong
    13. (1 articles) Chan Yun Kim
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    Ex-vivo multi-modal microscopy of healthy skin Investigating the correlation between white matter and microvasculature changes in aging using large scale optical coherence tomography and confocal fluorescence imaging combined with tissue sectioning Validating Intravascular Imaging with Serial Optical Coherence Tomography and Confocal Fluorescence Microscopy White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains Whole mouse brain imaging using optical coherence tomography: reconstruction, normalization, segmentation, and comparison with diffusion MRI Serial optical coherence scanning reveals an association between cardiac function and the heart architecture in the aging rodent heart Comparing three-dimensional serial optical coherence tomography histology to MRI imaging in the entire mouse brain Imaging whole mouse brains with a dual resolution serial swept-source optical coherence tomography scanner Factors Associated with Changes in Retinal Layers Following Acute Optic Neuritis: A Longitudinal Study Using Optical Coherence Tomography Relationship between N95 Amplitude of Pattern Electroretinogram and Optical Coherence Tomography Angiography in Open-Angle Glaucoma Historic Effort to 'End Blindness" Marks a Major Milestone with Leading Scientist Recognized for Pioneering Work at VIP Ceremony Featuring Tribute to Ruth Bader Ginsburg Healing and early stent coverage after ultrathin strut biodegradable polymer‐coated sirolimus‐eluting stent implantation: SiBi optical coherence tomography study