Ms. Audrey Laurence Profile

Audrey Laurence

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Publications (6)

SPIE Journal Paper | 11 November 2020 Open Access

Multispectral diffuse reflectance can discriminate blood vessels and bleeding during neurosurgery based on low-frequency hemodynamics

Audrey Laurence, Alain Bouthillier, Manon Robert, Dang Khoa Nguyen, Frédéric Leblond

JBO, Vol. 25, Issue 11, 116003, (November 2020) https://doi.org/10.1117/12.10.1117/1.JBO.25.11.116003

KEYWORDS: Blood vessels, Blood, Image segmentation, Hemodynamics, Reflectivity, Diffuse reflectance spectroscopy, Brain, Absorption, Tissues, Tissue optics

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Significance: The practicality of optical methods detecting tissue optical contrast (absorption, elastic and inelastic scattering, fluorescence) for surgical guidance is limited by interferences from blood pooling and the resulting partial or complete inability to interrogate cortex and blood vessels. Aim: A multispectral diffuse reflectance technique was developed for intraoperative brain imaging of hemodynamic activity to automatically discriminate blood vessels, cortex, and bleeding at the brain surface. Approach: A manual segmentation of blood pooling, cortex, and vessels allowed the identification of a frequency range in hemoglobin concentration variations associated with high optical signal in blood vessels and cortex but not in bleeding. Reflectance spectra were then used to automatically segment areas with and without hemodynamic activity as well as to discriminate blood from cortical areas. Results: The frequency range associated with low-frequency hemodynamics and respiratory rate (0.03 to 0.3 Hz) exhibits the largest differences in signal amplitudes for bleeding, blood vessels, and cortex. A segmentation technique based on simulated reflectance spectra initially allowed discrimination of blood (bleeding and vessels) from cortical tissue. Then, a threshold applied to the low-frequency components from deoxyhemoglobin allowed the segmentation of bleeding from vessels. A study on the minimum acquisition time needed to discriminate all three components determined that ∼25 s was necessary to detect changes in the low-frequency range. Other frequency ranges such as heartbeat (1 to 1.7 Hz) can be used to reduce the acquisition time to few seconds but would necessitate optimizing instrumentation to ensure larger signal-to-noise ratios are achieved. Conclusions: A method based on multispectral reflectance signals and low-frequency hemoglobin concentration changes can be used to distinguish bleeding, blood vessels, and cortex. This could be integrated into fiber optic probes to enhance signal specificity by providing users an indication of whether measurements are corrupted by blood pooling, an important confounding factor in biomedical optics applied to surgery.

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Proceedings Article | 11 July 2019 Paper

Multimodal imaging platform for surgical guidance during epilepsy surgery

Audrey Laurence, Emile Beaulieu, Dang Nguyen, Alain Bouthillier, Dominique Trudel, Frederic Leblond

Proceedings Volume 11074, 1107425 (2019) https://doi.org/10.1117/12.2527232

KEYWORDS: Epilepsy, Auto-fluorescence imaging, Imaging systems, Surgery, Hemodynamics, Microscopes, Multimodal imaging, Hyperspectral imaging, Optical properties, Luminescence

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Proceedings Article | 4 March 2019 Presentation

Post-prostatectomy spatial frequency domain imaging for positive margins identification using endogenous tissue fluorescence, absorption and scattering (Conference Presentation)

Emile Beaulieu, Audrey Laurence, Mathieu Latour, Roula Albadine, Dominique Trudel, Frédéric Leblond

Proceedings Volume 10871, 108710B (2019) https://doi.org/10.1117/12.2510067

KEYWORDS: Luminescence, Tissues, Absorption, Scattering, Prostate, Imaging systems, Cancer, Light scattering, Laser scattering, Laser tissue interaction

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SPIE Journal Paper | 12 October 2016 Open Access

Intraoperative video-rate hemodynamic response assessment in human cortex using snapshot hyperspectral optical imaging

Julien Pichette, Audrey Laurence, Leticia Angulo, Frederic Lesage, Alain Bouthillier, Dang Khoa Nguyen, Frédéric Leblond

NPh, Vol. 3, Issue 04, 045003, (October 2016) https://doi.org/10.1117/12.10.1117/1.NPh.3.4.045003

KEYWORDS: Hemodynamics, Tissue optics, Brain, Absorption, Optical imaging, Cameras, Hyperspectral imaging, Imaging systems, Calibration, Microscopes

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Proceedings Article | 26 April 2016 Presentation

Intraoperative brain hemodynamic response assessment with real-time hyperspectral optical imaging (Conference Presentation)

Audrey Laurence, Julien Pichette, Leticia Angulo-Rodríguez, Catherine Saint Pierre, Frédéric Lesage, Alain Bouthillier, Dang Khoa Nguyen, Frédéric Leblond

Proceedings Volume 9690, 96900E (2016) https://doi.org/10.1117/12.2213384

KEYWORDS: Hemodynamics, Brain, Hyperspectral imaging, Imaging systems, Neuroimaging, Optical imaging, Surgery, Mosaic detectors, Brain mapping, Cerebral blood flow

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Proceedings Article | 26 April 2016 Presentation

An intraoperative spectroscopic imaging system for quantification of Protoporphyrin IX during glioma surgery (Conference Presentation)

Leticia Angulo-Rodríguez, Audrey Laurence, Michael Jermyn, Guillaume Sheehy, Mira Sibai, Kevin Petrecca, David Roberts, Keith Paulsen, Brian Wilson, Frédéric Leblond

Proceedings Volume 9690, 96900F (2016) https://doi.org/10.1117/12.2213367

KEYWORDS: Imaging systems, Luminescence, Tissue optics, Imaging spectroscopy, Surgery, Cancer, Tissues, Spectroscopy, Brain, Tumors

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