1. Articles from Joël Lefebvre

    1-7 of 7
    1. 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 (25  μm  /  voxel) 3  ×   OCT with a high-resolution (1.5  μm  /  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, a multimodal and multiresolution registration pipeline is developed in order to align the 2R-SOCT data onto diffusion MRI (dMRI) data acquired in the same ex vivo mouse brains ...

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    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    1-7 of 7
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    1. (7 articles) Polytechnique Montreal
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