1. Frédéric Lesage

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    1. Mentioned In 16 Articles

    2. Fully automated dual-resolution serial optical coherence tomography aimed at diffusion MRI validation in whole mouse brains

      Fully automated dual-resolution serial optical coherence tomography aimed at diffusion MRI validation in whole mouse brains
      An automated dual-resolution serial optical coherence tomography (2R-SOCT) scanner is developed. The serial histology system combines a low-resolution (25m/voxel) 3 OCT with a high-resolution (1.5m/voxel) 40 OCT to acquire whole mouse brains at low resolution and to target specific regions of interest (ROIs) at high resolution. The 40 ROIs positions are selected either manually by the microscope operator or using an automated ROI positioning selection algorithm. Additionally ...
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    3. 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 ...
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    4. 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 ) m 3 (4.94.96.5)m3 stitched back together to give a three-dimensional map of the brain from which a template OCT brain was obtained. To ...
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    5. 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 ...
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    6. 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 m 4.94.96.5m . This paper describes techniques for reconstruction and segmentation of the sliced brains. In addition to the ...
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    7. 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 ...
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    8. 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 ...
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    9. Multimodal reconstruction of microvascular-flow distributions using combined two-photon microscopy and Doppler optical coherence tomography

      Multimodal reconstruction of microvascular-flow distributions using combined two-photon microscopy and Doppler optical coherence tomography
      Computing microvascular cerebral blood flow ( CBF ) in real cortical angiograms is challenging. Here, we investigated whether the use of Doppler optical coherence tomography (DOCT) flow measurements in individual vessel segments can help in reconstructing CBF across the entire vasculature of a truncated cortical angiogram. A CBF computational framework integrating DOCT measurements is presented. Simulations performed on a synthetic angiogram showed that the addition of DOCT measurements, especially close to large ...
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    10. 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
      ...e Castonguay ; Pramod K. Avti ; Mohammad Moeini ; Philippe Pouliot ; Maryam S. Tabatabaei ; Samuel Bélanger ; Frédéric Lesage; Investigating the correlation between white matter and microvasculature changes in aging usin...
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    11. Statistical intensity variation analysis for rapid volumetric imaging of capillary network flux

      Statistical intensity variation analysis for rapid volumetric imaging of capillary network flux
      We present a novel optical coherence tomography (OCT)-based technique for rapid volumetric imaging of red blood cell (RBC) flux in capillary networks. Previously we reported that OCT can capture individual RBC passage within a capillary, where the OCT intensity signal at a voxel fluctuates when an RBC passes the voxel. Based on this finding, we defined a metric of statistical intensity variation (SIV) and validated that the mean SIV ...
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    12. Multiple-capillary measurement of RBC speed, flux, and density with optical coherence tomography

      Multiple-capillary measurement of RBC speed, flux, and density with optical coherence tomography
      As capillaries exhibit heterogeneous and fluctuating dynamics even during baseline, a technique measuring red blood cell (RBC) speed and flux over many capillaries at the same time is needed. Here, we report that optical coherence tomography can capture individual RBC passage simultaneously over many capillaries located at different depths. Further, we demonstrate the ability to quantify RBC speed, flux, and linear density. This technique will provide a means to monitor ...
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    13. Catechin prevents severe dyslipidemia-associated changes in wall biomechanics of cerebral arteries in LDLr-/-:hApoB+/+ mice and improves cerebral blood flow

      Catechin prevents severe dyslipidemia-associated changes in wall biomechanics of cerebral arteries in LDLr-/-:hApoB+/+ mice and improves cerebral blood flow
      Endothelial dysfunction and oxidative stress contribute to the atherosclerotic process that includes stiffening of large peripheral arteries. In contrast, we previously reported a paradoxical increase in cerebrovascular compliance in LDLr-/-: hApoB+/+ atherosclerotic (ATX) mice. We hypothesized that prevention of cerebral artery endothelial function with a chronic dietary antioxidant intake would normalize the changes in cerebral artery wall structure and biomechanics and prevent the decline in basal cerebral blood flow (CBF ...
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    14. Measurement of cerebral microvascular compliance in a model of atherosclerosis with optical coherence tomography

      Measurement of cerebral microvascular compliance in a model of atherosclerosis with optical coherence tomography
      Optical coherence tomography (OCT) has recently been used to produce 3D angiography of microvasculature and blood flow maps of large vessels in the rodent brain in-vivo. However, use of this optical method for the study of cerebrovascular disease has not been fully explored. Recent developments in neurodegenerative diseases has linked common cardiovascular risk factors to neurodegenerative risk factors hinting at a vascular hypothesis for the development of the latter. Tools ...
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    15. Catechin treatment improves cerebrovascular flow-mediated dilation and learning abilities in atherosclerotic mice

      Catechin treatment improves cerebrovascular flow-mediated dilation and learning abilities in atherosclerotic mice
      Severe dyslipidemia and the associated oxidative stress, could accelerate the age-related decline in cerebrovascular endothelial function and cerebral blood flow (CBF), leading to neuronal loss and impaired learning abilities. We hypothesized that a chronic treatment with the polyphenol catechin would prevent endothelial dysfunction, maintain CBF responses and protect learning abilities in atherosclerotic (ATX) mice. We treated ATX (C57Bl/6-LDLR-/-hApoB+/+; 3 month-old, m/o) mice with catechin (30 mg/kg ...
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  2. About Frédéric Lesage

    Frédéric Lesage

    Frédéric Lesage is with the Department of Electrical Engineering, Polytechnique Montreal, Canada