2022
27.
Lloyd, Rachel; Walter, Jane; Pirikahu, Sarah; Cadby, Gemma; Hickey, Martha; Sampson, David D; Karnowski, Karol; Hackmann, Michael J; Saunders, Christobel; Lilge, Lothar; Stone, Jennifer
Assessment of repeated reference measurements to inform the validity of optical breast spectroscopy Journal Article
In: AIP Review of Scientific Instruments, 93 , 2022, ISBN: 1089-7623.
@article{nokey,
title = {Assessment of repeated reference measurements to inform the validity of optical breast spectroscopy},
author = {Rachel Lloyd and Jane Walter and Sarah Pirikahu and Gemma Cadby and Martha Hickey and David D Sampson and Karol Karnowski and Michael J Hackmann and Christobel Saunders and Lothar Lilge and Jennifer Stone},
doi = {10.1063/5.0072223},
isbn = {1089-7623},
year = {2022},
date = {2022-04-07},
urldate = {2022-04-07},
journal = {AIP Review of Scientific Instruments},
volume = {93},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
26.
Boguslawski, Jakub; Palczewska, Grażyna; Tomczewski, Sławomir; Milkiewicz, Jadwiga; Kasprzycki, Piotr; Stachowiak, Dorota; Komar, Katarzyna; Marzejon, Marcin J; Sikorski, Bartosz J; Hudzikowski, Arkadiusz; Głuszek, Aleksander; Łaszczych, Zbigniew; Karnowski, Karol; Soboń, Grzegorz; Palczewski, Krzysztof; Wojtkowski, Maciej
In vivo imaging of the human eye using a two-photon excited fluorescence scanning laser ophthalmoscope Journal Article
In: The Journal of Clinical Investigation, 2022, ISSN: 1558-8238.
@article{nokey,
title = {In vivo imaging of the human eye using a two-photon excited fluorescence scanning laser ophthalmoscope},
author = {Jakub Boguslawski and Grażyna Palczewska and Sławomir Tomczewski and Jadwiga Milkiewicz and Piotr Kasprzycki and Dorota Stachowiak and Katarzyna Komar and Marcin J Marzejon and Bartosz J Sikorski and Arkadiusz Hudzikowski and Aleksander Głuszek and Zbigniew Łaszczych and Karol Karnowski and Grzegorz Soboń and Krzysztof Palczewski and Maciej Wojtkowski},
doi = {10.1172/JCI154218},
issn = {1558-8238},
year = {2022},
date = {2022-01-18},
urldate = {2021-11-30},
journal = {The Journal of Clinical Investigation},
abstract = {Background: Noninvasive assessment of metabolic processes that sustain regeneration of human retinal visual pigments (visual cycle) is essential to improve ophthalmic diagnostics and to accelerate development of new treatments to counter retinal diseases. Fluorescent vitamin A derivatives, which are the chemical intermediates of these processes, are highly sensitive to UV light; thus, safe analyses of these processes in humans are currently beyond the reach of even the most modern ocular imaging modalities.
Methods: We present a compact fluorescence scanning laser ophthalmoscope (TPEF-SLO) and spectrally resolved images of the human retina based on two-photon excitation (TPE) with near-infrared (IR) light. A custom Er:fiber laser with integrated pulse selection, along with intelligent post-processing of data, enables excitation with low laser power and precise measurement of weak signals.
Results: We demonstrate spectrally resolved TPE fundus images of human subjects. Comparison of TPE data between human and mouse models of retinal diseases revealed similarity with mouse models that rapidly accumulate bisretinoid condensation products. Thus, visual cycle intermediates and toxic byproducts of this metabolic pathway can be measured and quantified by TPE imaging.
Conclusion: Our work establishes a TPE instrument and measurement method for noninvasive metabolic assessment of the human retina. This approach opens the possibility for monitoring eye diseases in the earliest stages before structural damage to the retina occurs.
Funding: NIH, Research to Prevent Blindness, Foundation for Polish Science, European Regional Development Fund, Polish National Agency for Academic Exchange and Polish Ministry of Science and Higher Education.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Noninvasive assessment of metabolic processes that sustain regeneration of human retinal visual pigments (visual cycle) is essential to improve ophthalmic diagnostics and to accelerate development of new treatments to counter retinal diseases. Fluorescent vitamin A derivatives, which are the chemical intermediates of these processes, are highly sensitive to UV light; thus, safe analyses of these processes in humans are currently beyond the reach of even the most modern ocular imaging modalities.
Methods: We present a compact fluorescence scanning laser ophthalmoscope (TPEF-SLO) and spectrally resolved images of the human retina based on two-photon excitation (TPE) with near-infrared (IR) light. A custom Er:fiber laser with integrated pulse selection, along with intelligent post-processing of data, enables excitation with low laser power and precise measurement of weak signals.
Results: We demonstrate spectrally resolved TPE fundus images of human subjects. Comparison of TPE data between human and mouse models of retinal diseases revealed similarity with mouse models that rapidly accumulate bisretinoid condensation products. Thus, visual cycle intermediates and toxic byproducts of this metabolic pathway can be measured and quantified by TPE imaging.
Conclusion: Our work establishes a TPE instrument and measurement method for noninvasive metabolic assessment of the human retina. This approach opens the possibility for monitoring eye diseases in the earliest stages before structural damage to the retina occurs.
Funding: NIH, Research to Prevent Blindness, Foundation for Polish Science, European Regional Development Fund, Polish National Agency for Academic Exchange and Polish Ministry of Science and Higher Education.
Methods: We present a compact fluorescence scanning laser ophthalmoscope (TPEF-SLO) and spectrally resolved images of the human retina based on two-photon excitation (TPE) with near-infrared (IR) light. A custom Er:fiber laser with integrated pulse selection, along with intelligent post-processing of data, enables excitation with low laser power and precise measurement of weak signals.
Results: We demonstrate spectrally resolved TPE fundus images of human subjects. Comparison of TPE data between human and mouse models of retinal diseases revealed similarity with mouse models that rapidly accumulate bisretinoid condensation products. Thus, visual cycle intermediates and toxic byproducts of this metabolic pathway can be measured and quantified by TPE imaging.
Conclusion: Our work establishes a TPE instrument and measurement method for noninvasive metabolic assessment of the human retina. This approach opens the possibility for monitoring eye diseases in the earliest stages before structural damage to the retina occurs.
Funding: NIH, Research to Prevent Blindness, Foundation for Polish Science, European Regional Development Fund, Polish National Agency for Academic Exchange and Polish Ministry of Science and Higher Education.
2021
25.
Untrcht, Gavrielle; Karnowski, Karol; Sampson, David D.
Imaging the small with the small: Prospects for photonics in micro-endomicroscopy for minimally invasive cellular-resolution bioimaging Journal Article
In: APL Photonics, 6 (6), pp. 060901, 2021, ISBN: 2378-0967.
@article{nokey,
title = {Imaging the small with the small: Prospects for photonics in micro-endomicroscopy for minimally invasive cellular-resolution bioimaging},
author = {Gavrielle Untrcht and Karol Karnowski and David D. Sampson},
doi = {10.1063/5.0052258},
isbn = {2378-0967},
year = {2021},
date = {2021-06-01},
urldate = {2021-06-01},
journal = {APL Photonics},
volume = {6},
number = {6},
pages = {060901},
abstract = {Many bioimaging studies, including those in engineered tissue constructs, intravital microscopy in animal models, and medical imaging in humans, require cellular-resolution imaging of structures deep within a sample. Yet, many of the current approaches are limited in terms of resolution, but also in invasiveness, repeatable imaging of the same location, and accessible imaging depth. We coin the term micro-endomicroscope to describe the emerging class of small, cellular-resolution endoscopic imaging systems designed to image cells in situ while minimizing perturbation of the sample. In this Perspective, we motivate the need for further development of micro-endomicroscopes, highlighting applications that would greatly benefit, reviewing progress, and considering how photonics might contribute. We identify areas ripe for technological development, such as micro-scanners and small lens systems, that would advance micro-endomicroscope performance. With the right developments in photonics, many possibilities exist for new minimally invasive translatable imaging tools across the scientific, pre-clinical, and clinical spectrum: from longitudinal studies of engineered tissue constructs, to tracking disease progression in animal models, to expanding the ability to diagnose and develop treatments for diseases without the need for invasive medical procedures.
},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Many bioimaging studies, including those in engineered tissue constructs, intravital microscopy in animal models, and medical imaging in humans, require cellular-resolution imaging of structures deep within a sample. Yet, many of the current approaches are limited in terms of resolution, but also in invasiveness, repeatable imaging of the same location, and accessible imaging depth. We coin the term micro-endomicroscope to describe the emerging class of small, cellular-resolution endoscopic imaging systems designed to image cells in situ while minimizing perturbation of the sample. In this Perspective, we motivate the need for further development of micro-endomicroscopes, highlighting applications that would greatly benefit, reviewing progress, and considering how photonics might contribute. We identify areas ripe for technological development, such as micro-scanners and small lens systems, that would advance micro-endomicroscope performance. With the right developments in photonics, many possibilities exist for new minimally invasive translatable imaging tools across the scientific, pre-clinical, and clinical spectrum: from longitudinal studies of engineered tissue constructs, to tracking disease progression in animal models, to expanding the ability to diagnose and develop treatments for diseases without the need for invasive medical procedures.
2020
24.
Curatolo, Andrea; Birkenfeld, Judith S.; Martinez-Enriquez, Eduardo; Germann, James A.; Muralidharan, Geethika; Palací, Jesús; Pascual, Daniel; Eliasy, Ashkan; Abass, Ahmed; Solarski, Jędrzej; Karnowski, Karol; Wojtkowski, Maciej; Elsheikh, Ahmed; Marcos, Susana
Multi-meridian corneal imaging of air-puff induced deformation for improved detection of biomechanical abnormalities Journal Article
In: Biomedical Optics Express, 11 (11), pp. 6337-6355, 2020, ISSN: 2156-7085.
@article{nokey,
title = {Multi-meridian corneal imaging of air-puff induced deformation for improved detection of biomechanical abnormalities},
author = {Andrea Curatolo and Judith S. Birkenfeld and Eduardo Martinez-Enriquez and James A. Germann and Geethika Muralidharan and Jesús Palací and Daniel Pascual and Ashkan Eliasy and Ahmed Abass and Jędrzej Solarski and Karol Karnowski and Maciej Wojtkowski and Ahmed Elsheikh and Susana Marcos},
doi = {10.1364/BOE.402402},
issn = {2156-7085},
year = {2020},
date = {2020-10-14},
urldate = {2020-10-14},
journal = {Biomedical Optics Express},
volume = {11},
number = {11},
pages = {6337-6355},
abstract = {Corneal biomechanics play a fundamental role in the genesis and progression of corneal pathologies, such as keratoconus; in corneal remodeling after corneal surgery; and in affecting the measurement accuracy of glaucoma biomarkers, such as the intraocular pressure (IOP). Air-puff induced corneal deformation imaging reveals information highlighting normal and pathological corneal response to a non-contact mechanical excitation. However, current commercial systems are limited to monitoring corneal deformation only on one corneal meridian. Here, we present a novel custom-developed swept-source optical coherence tomography (SSOCT) system, coupled with a collinear air-puff excitation, capable of acquiring dynamic corneal deformation on multiple meridians. Backed by numerical simulations of corneal deformations, we propose two different scan patterns, aided by low coil impedance galvanometric scan mirrors that permit an appropriate compromise between temporal and spatial sampling of the corneal deformation profiles. We customized the air-puff module to provide an unobstructed SSOCT field of view and different peak pressures, air-puff durations, and distances to the eye. We acquired multi-meridian corneal deformation profiles (a) in healthy human eyes in vivo, (b) in porcine eyes ex vivo under varying controlled IOP, and (c) in a keratoconus-mimicking porcine eye ex vivo. We detected deformation asymmetries, as predicted by numerical simulations, otherwise missed on a single meridian that will substantially aid in corneal biomechanics diagnostics and pathology screening.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Corneal biomechanics play a fundamental role in the genesis and progression of corneal pathologies, such as keratoconus; in corneal remodeling after corneal surgery; and in affecting the measurement accuracy of glaucoma biomarkers, such as the intraocular pressure (IOP). Air-puff induced corneal deformation imaging reveals information highlighting normal and pathological corneal response to a non-contact mechanical excitation. However, current commercial systems are limited to monitoring corneal deformation only on one corneal meridian. Here, we present a novel custom-developed swept-source optical coherence tomography (SSOCT) system, coupled with a collinear air-puff excitation, capable of acquiring dynamic corneal deformation on multiple meridians. Backed by numerical simulations of corneal deformations, we propose two different scan patterns, aided by low coil impedance galvanometric scan mirrors that permit an appropriate compromise between temporal and spatial sampling of the corneal deformation profiles. We customized the air-puff module to provide an unobstructed SSOCT field of view and different peak pressures, air-puff durations, and distances to the eye. We acquired multi-meridian corneal deformation profiles (a) in healthy human eyes in vivo, (b) in porcine eyes ex vivo under varying controlled IOP, and (c) in a keratoconus-mimicking porcine eye ex vivo. We detected deformation asymmetries, as predicted by numerical simulations, otherwise missed on a single meridian that will substantially aid in corneal biomechanics diagnostics and pathology screening.
23.
Karnowski, Karol; Li, Qingyun; Poudyal, Anima; Villiger, Martin; Farah, Camile S.; Sampson, David D.
Influence of tissue fixation on depth-resolved birefringence of oral cavity tissue samples Journal Article
In: Journal of Biomedical Optics, 25 (9), pp. 096003, 2020, ISSN: 1083-3668.
@article{nokey,
title = {Influence of tissue fixation on depth-resolved birefringence of oral cavity tissue samples},
author = {Karol Karnowski and Qingyun Li and Anima Poudyal and Martin Villiger and Camile S. Farah and David D. Sampson},
doi = {10.1117/1.JBO.25.9.096003},
issn = {1083-3668},
year = {2020},
date = {2020-09-10},
journal = {Journal of Biomedical Optics},
volume = {25},
number = {9},
pages = {096003},
abstract = {To advance our understanding of the contrast observed when imaging with polarization-sensitive optical coherence tomography (PS-OCT) and its correlation with oral cancerous pathologies, a detailed comparison with histology provided via ex vivo fixed tissue is required. The effects of tissue fixation, however, on such polarization-based contrast have not yet been investigated.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
To advance our understanding of the contrast observed when imaging with polarization-sensitive optical coherence tomography (PS-OCT) and its correlation with oral cancerous pathologies, a detailed comparison with histology provided via ex vivo fixed tissue is required. The effects of tissue fixation, however, on such polarization-based contrast have not yet been investigated.
22.
Dolezyczek, Hubert; Rapolu, Mounika; Niedzwiedziuk, Paulina; Karnowski, Karol; Borycki, Dawid; Dzwonek, Joanna; Wilczynski, Grzegorz; Malinowska, Monika; Wojtkowski, Maciej
Longitudinal in-vivo OCM imaging of glioblastoma development in the mouse brain Journal Article
In: Biomedical Optics Express, 11 (9), pp. 5003-5016, 2020, ISSN: 2156-7085.
@article{nokey,
title = {Longitudinal in-vivo OCM imaging of glioblastoma development in the mouse brain},
author = {Hubert Dolezyczek and Mounika Rapolu and Paulina Niedzwiedziuk and Karol Karnowski and Dawid Borycki and Joanna Dzwonek and Grzegorz Wilczynski and Monika Malinowska and Maciej Wojtkowski},
doi = {10.1364/BOE.400723},
issn = {2156-7085},
year = {2020},
date = {2020-08-12},
journal = {Biomedical Optics Express},
volume = {11},
number = {9},
pages = {5003-5016},
abstract = {We present in-vivo imaging of the mouse brain using custom made Gaussian beam optical coherence microscopy (OCM) with 800nm wavelength. We applied new instrumentation to longitudinal imaging of the glioblastoma (GBM) tumor microvasculature in the mouse brain. We have introduced new morphometric biomarkers that enable quantitative analysis of the development of GBM. We confirmed quantitatively an intensive angiogenesis in the tumor area between 3 and 14 days after GBM cells injection confirmed by considerably increased of morphometric parameters. Moreover, the OCM setup revealed heterogeneity and abnormality of newly formed vessels.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present in-vivo imaging of the mouse brain using custom made Gaussian beam optical coherence microscopy (OCM) with 800nm wavelength. We applied new instrumentation to longitudinal imaging of the glioblastoma (GBM) tumor microvasculature in the mouse brain. We have introduced new morphometric biomarkers that enable quantitative analysis of the development of GBM. We confirmed quantitatively an intensive angiogenesis in the tumor area between 3 and 14 days after GBM cells injection confirmed by considerably increased of morphometric parameters. Moreover, the OCM setup revealed heterogeneity and abnormality of newly formed vessels.
21.
Consejo, Alejandra; Solarski, Jędrzej; Karnowski, Karol; Rozema, Jos J; Wojtkowski, Maciej; Iskander, D. Robert
Keratoconus Detection Based on a Single Scheimpflug Image Journal Article
In: 9 (7), pp. 36, 2020, ISSN: 2164-2591.
@article{nokey,
title = {Keratoconus Detection Based on a Single Scheimpflug Image},
author = {Alejandra Consejo and Jędrzej Solarski and Karol Karnowski and Jos J Rozema and Maciej Wojtkowski and D. Robert Iskander},
doi = {10.1167/tvst.9.7.36},
issn = {2164-2591},
year = {2020},
date = {2020-06-26},
volume = {9},
number = {7},
pages = {36},
abstract = {Purpose: To introduce a new approach for keratoconus detection based on corneal microstructure observed in vivo derived from a single Scheimpflug image.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Purpose: To introduce a new approach for keratoconus detection based on corneal microstructure observed in vivo derived from a single Scheimpflug image.
20.
Gong, Peijun; Li, Qingyun; Wang, Qiang; Karnowski, Karol; Sampson, David D.
Jones matrix-based speckle-decorrelation angiography using polarization-sensitive optical coherence tomography Journal Article
In: Journal of Biophotonics, 13 (9), pp. e202000007, 2020, ISSN: 1864-0648.
@article{nokey,
title = {Jones matrix-based speckle-decorrelation angiography using polarization-sensitive optical coherence tomography},
author = {Peijun Gong and Qingyun Li and Qiang Wang and Karol Karnowski and David D. Sampson},
doi = {10.1002/jbio.202000007},
issn = {1864-0648},
year = {2020},
date = {2020-05-16},
journal = {Journal of Biophotonics},
volume = {13},
number = {9},
pages = {e202000007},
abstract = {We show that polarization-sensitive optical coherence tomography angiography (PS-OCTA) based on full Jones matrix assessment of speckle decorrelation offers improved contrast and depth of vessel imaging over conventional OCTA. We determine how best to combine the individual Jones matrix elements and compare the resulting image quality to that of a conventional OCT scanner by co-locating and imaging the same skin locations with closely matched scanning setups. Vessel projection images from finger and forearm skin demonstrate the benefits of Jones matrix-based PS-OCTA. Our study provides a promising starting point and a useful reference for future pre-clinical and clinical applications of Jones matrix-based PS-OCTA.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We show that polarization-sensitive optical coherence tomography angiography (PS-OCTA) based on full Jones matrix assessment of speckle decorrelation offers improved contrast and depth of vessel imaging over conventional OCTA. We determine how best to combine the individual Jones matrix elements and compare the resulting image quality to that of a conventional OCT scanner by co-locating and imaging the same skin locations with closely matched scanning setups. Vessel projection images from finger and forearm skin demonstrate the benefits of Jones matrix-based PS-OCTA. Our study provides a promising starting point and a useful reference for future pre-clinical and clinical applications of Jones matrix-based PS-OCTA.
19.
Li, Qingyun; Karnowski, Karol; Untracht, Gavrielle; Noble, Peter B.; Cense, Barry; Villiger, Martin; Sampson, David D.
Vectorial birefringence imaging by optical coherence microscopy for assessing fibrillar microstructures in the cornea and limbus Journal Article
In: Biomedical Optics Express, 11 (2), pp. 1122-1138, 2020, ISSN: 2156-7085.
@article{nokey,
title = {Vectorial birefringence imaging by optical coherence microscopy for assessing fibrillar microstructures in the cornea and limbus},
author = {Qingyun Li and Karol Karnowski and Gavrielle Untracht and Peter B. Noble and Barry Cense and Martin Villiger and David D. Sampson},
doi = {10.1364/BOE.382755},
issn = {2156-7085},
year = {2020},
date = {2020-01-24},
journal = {Biomedical Optics Express},
volume = {11},
number = {2},
pages = {1122-1138},
abstract = {The organization of fibrillar tissue on the micrometer scale carries direct implications for health and disease but remains difficult to assess in vivo. Polarization-sensitive optical coherence tomography measures birefringence, which relates to the microscopic arrangement of fibrillar tissue components. Here, we demonstrate a critical improvement in leveraging this contrast mechanism by employing the improved spatial resolution of focus-extended optical coherence microscopy (1.4 µm axially in air and 1.6 µm laterally, over more than 70 µm depth of field). Vectorial birefringence imaging of sheep cornea ex vivo reveals its lamellar organization into thin sections with distinct local optic axis orientations, paving the way to resolving similar features in vivo.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The organization of fibrillar tissue on the micrometer scale carries direct implications for health and disease but remains difficult to assess in vivo. Polarization-sensitive optical coherence tomography measures birefringence, which relates to the microscopic arrangement of fibrillar tissue components. Here, we demonstrate a critical improvement in leveraging this contrast mechanism by employing the improved spatial resolution of focus-extended optical coherence microscopy (1.4 µm axially in air and 1.6 µm laterally, over more than 70 µm depth of field). Vectorial birefringence imaging of sheep cornea ex vivo reveals its lamellar organization into thin sections with distinct local optic axis orientations, paving the way to resolving similar features in vivo.
2019
18.
Consejo, Alejandra; Gławdecka, Karolina; Karnowski, Karol; Solarski, Jędrzej; Rozema, Jos J.; Wojtkowski, Maciej; Iskander, D. Robert
Corneal properties of keratoconus based on Scheimpflug light intensity distribution Journal Article
In: Investigative Ophthalmology & Visual Science, 60 (8), pp. 3197-3203, 2019, ISSN: 1552-5783.
@article{nokey,
title = {Corneal properties of keratoconus based on Scheimpflug light intensity distribution},
author = {Alejandra Consejo and Karolina Gławdecka and Karol Karnowski and Jędrzej Solarski and Jos J. Rozema and Maciej Wojtkowski and D. Robert Iskander},
doi = {10.1167/iovs.19-26963},
issn = {1552-5783},
year = {2019},
date = {2019-06-18},
journal = {Investigative Ophthalmology & Visual Science},
volume = {60},
number = {8},
pages = {3197-3203},
abstract = {Purpose: We introduce a new approach to assess the properties of corneal microstructure in vivo of healthy control and keratoconus eyes, based on statistical modeling of light intensity distribution from Scheimpflug images.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Purpose: We introduce a new approach to assess the properties of corneal microstructure in vivo of healthy control and keratoconus eyes, based on statistical modeling of light intensity distribution from Scheimpflug images.
17.
Walther, Julia; Li, Qingyun; Villiger, Martin; Farah, Camile S.; Koch, Edmund; Karnowski, Karol; Sampson, David D.
Depth-resolved birefringence imaging of collagen fiber organization in the human oral mucosa in vivo Journal Article
In: Biomedical Optics Express, 10 (4), pp. 1942-1956, 2019, ISSN: 2156-7085.
@article{nokey,
title = {Depth-resolved birefringence imaging of collagen fiber organization in the human oral mucosa in vivo},
author = {Julia Walther and Qingyun Li and Martin Villiger and Camile S. Farah and Edmund Koch and Karol Karnowski and David D. Sampson},
doi = {10.1364/BOE.10.001942},
issn = {2156-7085},
year = {2019},
date = {2019-03-22},
journal = {Biomedical Optics Express},
volume = {10},
number = {4},
pages = {1942-1956},
abstract = {Stromal collagen organization has been identified as a potential prognostic indicator in a variety of cancers and other diseases accompanied by fibrosis. Changes in the connective tissue are increasingly considered for grading dysplasia and progress of oral squamous cell carcinoma, investigated mainly ex vivo by histopathology. In this study, polarization-sensitive optical coherence tomography (PS-OCT) with local phase retardation imaging is used for the first time to visualize depth-resolved (i.e., local) birefringence of healthy human oral mucosa in vivo. Depth-resolved birefringence is shown to reveal the expected local collagen organization. To demonstrate proof-of-principle, 3D image stacks were acquired at labial and lingual locations of the oral mucosa, chosen as those most commonly affected by cancerous alterations. To enable an intuitive evaluation of the birefringence images suitable for clinical application, color depth-encoded en-face projections were generated. Compared to en-face views of intensity or conventional cumulative phase retardation, we show that this novel approach offers improved visualization of the mucosal connective tissue layer in general, and reveals the collagen fiber architecture in particular. This study provides the basis for future prospective pathological and comparative in vivo studies non-invasively assessing stromal changes in conspicuous and cancerous oral lesions at different stages.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Stromal collagen organization has been identified as a potential prognostic indicator in a variety of cancers and other diseases accompanied by fibrosis. Changes in the connective tissue are increasingly considered for grading dysplasia and progress of oral squamous cell carcinoma, investigated mainly ex vivo by histopathology. In this study, polarization-sensitive optical coherence tomography (PS-OCT) with local phase retardation imaging is used for the first time to visualize depth-resolved (i.e., local) birefringence of healthy human oral mucosa in vivo. Depth-resolved birefringence is shown to reveal the expected local collagen organization. To demonstrate proof-of-principle, 3D image stacks were acquired at labial and lingual locations of the oral mucosa, chosen as those most commonly affected by cancerous alterations. To enable an intuitive evaluation of the birefringence images suitable for clinical application, color depth-encoded en-face projections were generated. Compared to en-face views of intensity or conventional cumulative phase retardation, we show that this novel approach offers improved visualization of the mucosal connective tissue layer in general, and reveals the collagen fiber architecture in particular. This study provides the basis for future prospective pathological and comparative in vivo studies non-invasively assessing stromal changes in conspicuous and cancerous oral lesions at different stages.
2018
16.
Li, Qingyun; Karnowski, Karol; Noble, Peter B.; Cairncross, Alvenia; James, Alan; Villiger, Martin; Sampson, David D.
Robust reconstruction of local optic axis orientation with fiber-based polarization-sensitive optical coherence tomography Journal Article
In: Biomedical Optics Express, 9 (11), pp. 5437-5455, 2018.
@article{nokey,
title = {Robust reconstruction of local optic axis orientation with fiber-based polarization-sensitive optical coherence tomography},
author = {Qingyun Li and Karol Karnowski and Peter B. Noble and Alvenia Cairncross and Alan James and Martin Villiger and David D. Sampson},
doi = {10.1364/BOE.9.005437},
year = {2018},
date = {2018-10-15},
journal = {Biomedical Optics Express},
volume = {9},
number = {11},
pages = {5437-5455},
abstract = {It is challenging to recover local optic axis orientation from samples probed with fiber-based polarization-sensitive optical coherence tomography (PS-OCT). In addition to the effect of preceding tissue layers, the transmission through fiber and system elements, and imperfect system alignment, need to be compensated. Here, we present a method to retrieve the required correction factors from measurements with depth-multiplexed PS-OCT, which accurately measures the full Jones matrix. The correction considers both retardation and diattenuation and is applied in the wavenumber domain, preserving the axial resolution of the system. The robustness of the method is validated by measuring a birefringence phantom with a misaligned system. Imaging ex-vivo lamb trachea and human bronchus demonstrates the utility of reconstructing the local optic axis orientation to assess smooth muscle, which is expected to be useful in the assessment of airway smooth muscle thickness in asthma, amongst other fiber-based applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
It is challenging to recover local optic axis orientation from samples probed with fiber-based polarization-sensitive optical coherence tomography (PS-OCT). In addition to the effect of preceding tissue layers, the transmission through fiber and system elements, and imperfect system alignment, need to be compensated. Here, we present a method to retrieve the required correction factors from measurements with depth-multiplexed PS-OCT, which accurately measures the full Jones matrix. The correction considers both retardation and diattenuation and is applied in the wavenumber domain, preserving the axial resolution of the system. The robustness of the method is validated by measuring a birefringence phantom with a misaligned system. Imaging ex-vivo lamb trachea and human bronchus demonstrates the utility of reconstructing the local optic axis orientation to assess smooth muscle, which is expected to be useful in the assessment of airway smooth muscle thickness in asthma, amongst other fiber-based applications.
15.
Maczynska, Ewa; Karnowski, Karol; Szulzycki, Krzysztof; Malinowska, Monika; Dolezyczek, Hubert; Cichanski, Artur; Wojtkowski, Maciej; Kaluzny, Bartlomiej; Grulkowski, Ireneusz
In: Journal of Biophotonics, 12 (2), pp. e201800154, 2018, ISSN: 1864-0648.
@article{nokey,
title = {Assessment of the influence of viscoelasticity of cornea in animal ex vivo model using air-puff optical coherence tomography and corneal hysteresis},
author = {Ewa Maczynska and Karol Karnowski and Krzysztof Szulzycki and Monika Malinowska and Hubert Dolezyczek and Artur Cichanski and Maciej Wojtkowski and Bartlomiej Kaluzny and Ireneusz Grulkowski},
doi = {10.1002/jbio.201800154},
issn = {1864-0648},
year = {2018},
date = {2018-09-18},
urldate = {2019-09-18},
journal = {Journal of Biophotonics},
volume = {12},
number = {2},
pages = {e201800154},
abstract = {Application of the air-puff swept source optical coherence tomography (SS-OCT) instrument to determine the influence of viscoelasticity on the relation between overall the air-puff force and corneal apex displacement of porcine corneas ex vivo is demonstrated. Simultaneous recording of time-evolution of the tissue displacement and air pulse stimulus allows obtaining valuable information related in part to the mechanical properties of the cornea. A novel approach based on quantitative analysis of the corneal hysteresis of OCT data is presented. The corneal response to the air pulse is assessed for different well-controlled intraocular pressure (IOP) levels and for the progression of cross-linking-induced stiffness of the cornea. Micrometer resolution, fast acquisition and noncontact character of the air-puff SS-OCT measurements have potential to improve the in vivo assessment of mechanical properties of the human corneas.
},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Application of the air-puff swept source optical coherence tomography (SS-OCT) instrument to determine the influence of viscoelasticity on the relation between overall the air-puff force and corneal apex displacement of porcine corneas ex vivo is demonstrated. Simultaneous recording of time-evolution of the tissue displacement and air pulse stimulus allows obtaining valuable information related in part to the mechanical properties of the cornea. A novel approach based on quantitative analysis of the corneal hysteresis of OCT data is presented. The corneal response to the air pulse is assessed for different well-controlled intraocular pressure (IOP) levels and for the progression of cross-linking-induced stiffness of the cornea. Micrometer resolution, fast acquisition and noncontact character of the air-puff SS-OCT measurements have potential to improve the in vivo assessment of mechanical properties of the human corneas.
14.
Gong, Peijun; Yu, Dao-Yi; Wang, Qiang; Yu, Paula K.; Karnowski, Karol; Heisler, Morgan; Francke, Ashley; An, Dong; Sarunic, Marinko V.; Sampson, David D.
Label-free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography Journal Article
In: Journal of Biophotonics, 11 (8), pp. e201800070, 2018, ISSN: 1864-0648.
@article{nokey,
title = {Label-free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography},
author = {Peijun Gong and Dao-Yi Yu and Qiang Wang and Paula K. Yu and Karol Karnowski and Morgan Heisler and Ashley Francke and Dong An and Marinko V. Sarunic and David D. Sampson},
doi = {10.1002/jbio.201800070},
issn = {1864-0648},
year = {2018},
date = {2018-06-19},
journal = {Journal of Biophotonics},
volume = {11},
number = {8},
pages = {e201800070},
abstract = {We employ optical coherence tomography (OCT) and optical coherence microscopy (OCM) to study conjunctival lymphatics in porcine eyes ex vivo. This study is a precursor to the development of in vivo imaging of the collecting lymphatics for potentially guiding and monitoring glaucoma filtration surgery. OCT scans at 1300 nm and higher-resolution OCM scans at 785 nm reveal the lymphatic vessels via their optical transparency. Equivalent signal characteristics are also observed from blood vessels largely free of blood (and devoid of flow) in the ex vivo conjunctiva. In our lymphangiography, vessel networks were segmented by compensating the depth attenuation in the volumetric OCT/OCM signal, projecting the minimum intensity in two dimensions and thresholding to generate a three-dimensional vessel volume. Vessel segmentation from multiple locations of a range of porcine eyes (n = 21) enables visualization of the vessel networks and indicates the varying spatial distribution of patent lymphatics. Such visualization provides a new tool to investigate conjunctival vessels in tissue ex vivo without need for histological tissue processing and a valuable reference on vessel morphology for the in vivo label-free imaging studies of lymphatics to follow.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We employ optical coherence tomography (OCT) and optical coherence microscopy (OCM) to study conjunctival lymphatics in porcine eyes ex vivo. This study is a precursor to the development of in vivo imaging of the collecting lymphatics for potentially guiding and monitoring glaucoma filtration surgery. OCT scans at 1300 nm and higher-resolution OCM scans at 785 nm reveal the lymphatic vessels via their optical transparency. Equivalent signal characteristics are also observed from blood vessels largely free of blood (and devoid of flow) in the ex vivo conjunctiva. In our lymphangiography, vessel networks were segmented by compensating the depth attenuation in the volumetric OCT/OCM signal, projecting the minimum intensity in two dimensions and thresholding to generate a three-dimensional vessel volume. Vessel segmentation from multiple locations of a range of porcine eyes (n = 21) enables visualization of the vessel networks and indicates the varying spatial distribution of patent lymphatics. Such visualization provides a new tool to investigate conjunctival vessels in tissue ex vivo without need for histological tissue processing and a valuable reference on vessel morphology for the in vivo label-free imaging studies of lymphatics to follow.
13.
Grulkowski, Ireneusz; Manzanera, Silvestre; Cwiklinski, Lukasz; Sobczuk, Franciszek; Karnowski, Karol; Artal, Pablo
Swept source optical coherence tomography and tunable lens technology for comprehensive imaging and biometry of the whole eye Journal Article
In: Optica, 5 (1), pp. 52-59, 2018, ISSN: 2334-2536.
@article{nokey,
title = {Swept source optical coherence tomography and tunable lens technology for comprehensive imaging and biometry of the whole eye},
author = {Ireneusz Grulkowski and Silvestre Manzanera and Lukasz Cwiklinski and Franciszek Sobczuk and Karol Karnowski and Pablo Artal},
doi = {10.1364/OPTICA.5.000052},
issn = {2334-2536},
year = {2018},
date = {2018-01-18},
journal = {Optica},
volume = {5},
number = {1},
pages = {52-59},
abstract = {Standard optical systems in ophthalmology are strictly dedicated either to retinal or to anterior segment imaging due to the refractive properties of the eye. We demonstrate a swept source optical coherence tomography platform with an electrically tunable lens (ETL) for versatile 3D in vivo imaging of both the eye’s anterior segment and the retina. The optimized optical setup with adaptive operational states of the ETL permits focusing on the retina and on the anterior segment. Dynamic control of the optical beam focus allows for OCT image enhancement, leading to the visualization of the vitreous details at both the vitreo-lenticular and vitreo-retinal attachment sites in an unprecedented manner. ETL tuning enables sequential visualization of the anterior and posterior segment of the eye, and such whole eye imaging can be also used to perform quantitative ocular biometry.
},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Standard optical systems in ophthalmology are strictly dedicated either to retinal or to anterior segment imaging due to the refractive properties of the eye. We demonstrate a swept source optical coherence tomography platform with an electrically tunable lens (ETL) for versatile 3D in vivo imaging of both the eye’s anterior segment and the retina. The optimized optical setup with adaptive operational states of the ETL permits focusing on the retina and on the anterior segment. Dynamic control of the optical beam focus allows for OCT image enhancement, leading to the visualization of the vitreous details at both the vitreo-lenticular and vitreo-retinal attachment sites in an unprecedented manner. ETL tuning enables sequential visualization of the anterior and posterior segment of the eye, and such whole eye imaging can be also used to perform quantitative ocular biometry.
2017
12.
Karnowski, Karol; Ajduk, Anna; Wieloch, Bartosz; Tamborski, Szymon; Krawiec, Krzysztof; Wojtkowski, Maciej; Szkulmowski, Maciej
Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos Journal Article
In: Scientific Reports , 7 , pp. 4165, 2017, ISSN: 2045-2322.
@article{nokey,
title = {Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos},
author = {Karol Karnowski and Anna Ajduk and Bartosz Wieloch and Szymon Tamborski and Krzysztof Krawiec and Maciej Wojtkowski and Maciej Szkulmowski },
doi = {10.1038/s41598-017-04220-8},
issn = {2045-2322},
year = {2017},
date = {2017-06-23},
journal = {Scientific Reports },
volume = {7},
pages = {4165},
abstract = {Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy
has delivered an enormous amount of information critical for understanding biological processes in
single cells. However, the requirement for a high numerical aperture and fluorescent markers still
limits researchers’ ability to visualize the cellular architecture without causing short- and long-term
photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the
technical limitations of fluorescence imaging techniques and provides unique access to fundamental
aspects of early embryonic development, without the requirement for sample pre-processing or
labeling. In the present paper, we utilized the internal motion of cytoplasm, as well as custom scanning
and signal processing protocols, to effectively reduce the speckle noise typical for standard OCM and
enable high-resolution intracellular time-lapse imaging. To test our imaging system we used mouse and
pig oocytes and embryos and visualized them through fertilization and the first embryonic division, as
well as at selected stages of oogenesis and preimplantation development. Because all morphological
and morphokinetic properties recorded by OCM are believed to be biomarkers of oocyte/embryo
quality, OCM may represent a new chapter in imaging-based preimplantation embryo diagnostics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy
has delivered an enormous amount of information critical for understanding biological processes in
single cells. However, the requirement for a high numerical aperture and fluorescent markers still
limits researchers’ ability to visualize the cellular architecture without causing short- and long-term
photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the
technical limitations of fluorescence imaging techniques and provides unique access to fundamental
aspects of early embryonic development, without the requirement for sample pre-processing or
labeling. In the present paper, we utilized the internal motion of cytoplasm, as well as custom scanning
and signal processing protocols, to effectively reduce the speckle noise typical for standard OCM and
enable high-resolution intracellular time-lapse imaging. To test our imaging system we used mouse and
pig oocytes and embryos and visualized them through fertilization and the first embryonic division, as
well as at selected stages of oogenesis and preimplantation development. Because all morphological
and morphokinetic properties recorded by OCM are believed to be biomarkers of oocyte/embryo
quality, OCM may represent a new chapter in imaging-based preimplantation embryo diagnostics.
has delivered an enormous amount of information critical for understanding biological processes in
single cells. However, the requirement for a high numerical aperture and fluorescent markers still
limits researchers’ ability to visualize the cellular architecture without causing short- and long-term
photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the
technical limitations of fluorescence imaging techniques and provides unique access to fundamental
aspects of early embryonic development, without the requirement for sample pre-processing or
labeling. In the present paper, we utilized the internal motion of cytoplasm, as well as custom scanning
and signal processing protocols, to effectively reduce the speckle noise typical for standard OCM and
enable high-resolution intracellular time-lapse imaging. To test our imaging system we used mouse and
pig oocytes and embryos and visualized them through fertilization and the first embryonic division, as
well as at selected stages of oogenesis and preimplantation development. Because all morphological
and morphokinetic properties recorded by OCM are believed to be biomarkers of oocyte/embryo
quality, OCM may represent a new chapter in imaging-based preimplantation embryo diagnostics.
2015
11.
Nowak, Jan Krzysztof; Grulkowski, Ireneusz; Karnowski, Karol; Wojtkowski, Maciej; Walkowiak, Jaroslaw
Optical Coherence Tomography of the Labial Salivary Glands Reveals Age-Related Differences in Women Journal Article
In: Clinical and Translational Science, 8 (6), pp. 717-21, 2015, ISSN: 1752-8062.
@article{nokey,
title = {Optical Coherence Tomography of the Labial Salivary Glands Reveals Age-Related Differences in Women},
author = {Jan Krzysztof Nowak and Ireneusz Grulkowski and Karol Karnowski and Maciej Wojtkowski and Jaroslaw Walkowiak},
doi = {10.1111/cts.12344},
issn = {1752-8062},
year = {2015},
date = {2015-11-04},
journal = {Clinical and Translational Science},
volume = {8},
number = {6},
pages = {717-21},
abstract = {The labial minor salivary glands (LSGs) play a role in medical research and practice due to their superficial location and involvement in both systemic and localized diseases. Swept-source optical coherence tomography (OCT) is a noninvasive modality that enables in vivo, micrometer resolution, wide-field three-dimensional imaging in seconds. A purpose-built swept-source OCT instrument was employed to acquire three-dimensional datasets covering the area of 2.43 cm2 of the mucosa of the lower lip to the depth of 3.4 mm in young (n = 14; mean age ± SD: 27 ± 3 years; body mass index [BMI] 20.4 ± 2.3 kg/m2) and middle-aged women (n = 11; 54 ± 6 years; 25.5 ± 3.2 kg/m2). Glandular tissue reflectivity mode (range 0–255; 86 ± 17 vs. 68 ± 12, p = 0.005), average single LSG area in tissue sample (5.26 ± 2.62 mm2 vs. 2.87 ± 1.26 mm2, p = 0.011), and LSG surface filling factor (0.23 ± 0.13 vs. 0.11 ± 0.10, p = 0.027) had higher values in younger than in middle-aged women. A correlation between BMI and glandular tissue reflectivity mode (Spearman's ρ = –0.60) was found (p = 0.002). The results highlight the potential value of LSGs’ OCT morphometry in research regarding ageing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The labial minor salivary glands (LSGs) play a role in medical research and practice due to their superficial location and involvement in both systemic and localized diseases. Swept-source optical coherence tomography (OCT) is a noninvasive modality that enables in vivo, micrometer resolution, wide-field three-dimensional imaging in seconds. A purpose-built swept-source OCT instrument was employed to acquire three-dimensional datasets covering the area of 2.43 cm2 of the mucosa of the lower lip to the depth of 3.4 mm in young (n = 14; mean age ± SD: 27 ± 3 years; body mass index [BMI] 20.4 ± 2.3 kg/m2) and middle-aged women (n = 11; 54 ± 6 years; 25.5 ± 3.2 kg/m2). Glandular tissue reflectivity mode (range 0–255; 86 ± 17 vs. 68 ± 12, p = 0.005), average single LSG area in tissue sample (5.26 ± 2.62 mm2 vs. 2.87 ± 1.26 mm2, p = 0.011), and LSG surface filling factor (0.23 ± 0.13 vs. 0.11 ± 0.10, p = 0.027) had higher values in younger than in middle-aged women. A correlation between BMI and glandular tissue reflectivity mode (Spearman's ρ = –0.60) was found (p = 0.002). The results highlight the potential value of LSGs’ OCT morphometry in research regarding ageing.
10.
Butler, Thomas; Slepneva, Svetlana; O’Shaughnessy, Ben; Kelleher, Bryan; Goulding, David; Hegarty, Stephen P.; Lyu, Hong-Chou; Karnowski, Karol; Wojtkowski, Maciej; and Guillaume Huyet,
Single shot, time-resolved measurement of the coherence properties of OCT swept source laser Journal Article
In: Optics Letters, 40 (10), pp. 2277-2280, 2015, ISSN: 0146-9592.
@article{nokey,
title = {Single shot, time-resolved measurement of the coherence properties of OCT swept source laser},
author = {Thomas Butler and Svetlana Slepneva and Ben O’Shaughnessy and Bryan Kelleher and David Goulding and Stephen P. Hegarty and Hong-Chou Lyu and Karol Karnowski and Maciej Wojtkowski and and Guillaume Huyet},
doi = {doi.org/10.1364/OL.40.002277},
issn = {0146-9592},
year = {2015},
date = {2015-05-07},
urldate = {2015-05-07},
journal = {Optics Letters},
volume = {40},
number = {10},
pages = {2277-2280},
abstract = {A novel, time-resolved interferometric technique is presented that allows the reconstruction of the complex electric field output of a swept source laser in a single-shot measurement. The power of the technique is demonstrated by examining a short cavity swept source designed for optical coherence tomography (OCT) applications with a spectral width of over 100 nm. The novel analysis allows a time-resolved real-time characterization of the roll-off, optical spectrum, linewidth, and coherence properties of a dynamic, rapidly swept laser source.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A novel, time-resolved interferometric technique is presented that allows the reconstruction of the complex electric field output of a swept source laser in a single-shot measurement. The power of the technique is demonstrated by examining a short cavity swept source designed for optical coherence tomography (OCT) applications with a spectral width of over 100 nm. The novel analysis allows a time-resolved real-time characterization of the roll-off, optical spectrum, linewidth, and coherence properties of a dynamic, rapidly swept laser source.
9.
Nowak, Jan K.; Grulkowski, Ireneusz; Karnowski, Karol; Wojtkowski, Maciej; Walkowiak, Jaroslaw
Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis Journal Article
In: PLOS ONE, 10 (1), pp. e0117517, 2015.
@article{nokey,
title = {Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis},
author = {Jan K. Nowak and Ireneusz Grulkowski and Karol Karnowski and Maciej Wojtkowski and Jaroslaw Walkowiak},
doi = {10.1371/journal.pone.0117517},
year = {2015},
date = {2015-01-26},
journal = {PLOS ONE},
volume = {10},
number = {1},
pages = { e0117517},
abstract = {The labial minor salivary glands (LSGs) are easily accessible mucus-secreting structures of the alimentary tract that may provide new information on the basis of gastrointestinal complications of cystic fibrosis (CF). It was shown that they are destructed in the course of cystic fibrosis. We employed wide-field, micrometer resolution in vivo optical coherence tomography to assess the surface density of LSGs in 18 patients with CF and 18 healthy subjects. The median LSGs’ surface densities in CF patients, and in the control group were 4.32 glands/cm2 and 6.58 glands/cm2, respectively (p = 0.006; Mann-Whitney U test). A lower LSG surface density is a previously unrecognized CF-related pathology of the alimentary tract.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The labial minor salivary glands (LSGs) are easily accessible mucus-secreting structures of the alimentary tract that may provide new information on the basis of gastrointestinal complications of cystic fibrosis (CF). It was shown that they are destructed in the course of cystic fibrosis. We employed wide-field, micrometer resolution in vivo optical coherence tomography to assess the surface density of LSGs in 18 patients with CF and 18 healthy subjects. The median LSGs’ surface densities in CF patients, and in the control group were 4.32 glands/cm2 and 6.58 glands/cm2, respectively (p = 0.006; Mann-Whitney U test). A lower LSG surface density is a previously unrecognized CF-related pathology of the alimentary tract.
2014
8.
Karnowski, Karol; Grulkowski, Ireneusz; Mohan, Nishant; Cox, Ian; and Maciej Wojtkowski,
Quantitative optical inspection of contact lenses immersed in wet cell using swept source OCT Journal Article
In: Optics Letters, 39 (16), pp. 4727-4730, 2014, ISSN: 0146-9592.
@article{nokey,
title = {Quantitative optical inspection of contact lenses immersed in wet cell using swept source OCT},
author = {Karol Karnowski and Ireneusz Grulkowski and Nishant Mohan and Ian Cox and and Maciej Wojtkowski},
doi = {10.1364/OL.39.004727},
issn = {0146-9592},
year = {2014},
date = {2014-08-06},
urldate = {2014-08-06},
journal = {Optics Letters},
volume = {39},
number = {16},
pages = {4727-4730},
abstract = {We demonstrate swept source optical coherence tomography (OCT) imaging of contact lenses (CLs) in a wet cell and comprehensive quantitative characterization of CLs from volumetric OCT datasets. The approach is based on a technique developed for lens autopositioning and autoleveling enabled by lateral capillary interactions between the wet cell wall and the lens floating on the liquid surface. The demonstrated OCT imaging has enhanced contrast due to the application of a scattering medium and it improves visualization of both CL interfaces and edges. We also present precise and accurate three-dimensional metrology of soft and rigid CLs based on the OCT data. The accuracy and precision of the extracted lens parameters are compared with the manufacturer’s specifications. The presented methodology facilitates industrial inspection methods of the CLs.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We demonstrate swept source optical coherence tomography (OCT) imaging of contact lenses (CLs) in a wet cell and comprehensive quantitative characterization of CLs from volumetric OCT datasets. The approach is based on a technique developed for lens autopositioning and autoleveling enabled by lateral capillary interactions between the wet cell wall and the lens floating on the liquid surface. The demonstrated OCT imaging has enhanced contrast due to the application of a scattering medium and it improves visualization of both CL interfaces and edges. We also present precise and accurate three-dimensional metrology of soft and rigid CLs based on the OCT data. The accuracy and precision of the extracted lens parameters are compared with the manufacturer’s specifications. The presented methodology facilitates industrial inspection methods of the CLs.
7.
Slepneva, Svetlana; O’Shaughnessy, Ben; Kelleher, Bryan; Hegarty, Stephen P.; Vladimirov, Andrei; Lyu, Honh-Chou; Karnowski, Karol; Wojtkowski, Maciej; Huyet, Guillaume
Dynamics of a short cavity swept source OCT laser Journal Article
In: Optics Express, 22 (15), pp. 18177-18185, 2014, ISSN: 1094-4087.
@article{nokey,
title = {Dynamics of a short cavity swept source OCT laser},
author = {Svetlana Slepneva and Ben O’Shaughnessy and Bryan Kelleher and Stephen P. Hegarty and Andrei Vladimirov and Honh-Chou Lyu and Karol Karnowski and Maciej Wojtkowski and Guillaume Huyet},
doi = {10.1364/OE.22.018177},
issn = {1094-4087},
year = {2014},
date = {2014-07-21},
journal = {Optics Express},
volume = {22},
number = {15},
pages = {18177-18185},
abstract = {We investigate the behaviour of a short cavity swept source laser with an intra cavity swept filter both experimentally and theoretically. We characterise the behaviour of the device with real-time intensity measurements using a fast digital oscilloscope, showing several distinct regimes, most notably regions of mode-hopping, frequency sliding mode-locking and chaos. A delay differential equation model is proposed that shows close agreement with the experimental results. The model is also used to determine important quantities such as the minimum and maximum sweep speeds for the mode-locking regime. It is also shown that by varying the filter width the maximum sweep speed can be increased but at a cost of increasing the instantaneous linewidth. The consequent impacts on optical coherence tomography applications are analysed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We investigate the behaviour of a short cavity swept source laser with an intra cavity swept filter both experimentally and theoretically. We characterise the behaviour of the device with real-time intensity measurements using a fast digital oscilloscope, showing several distinct regimes, most notably regions of mode-hopping, frequency sliding mode-locking and chaos. A delay differential equation model is proposed that shows close agreement with the experimental results. The model is also used to determine important quantities such as the minimum and maximum sweep speeds for the mode-locking regime. It is also shown that by varying the filter width the maximum sweep speed can be increased but at a cost of increasing the instantaneous linewidth. The consequent impacts on optical coherence tomography applications are analysed.
2013
6.
Grulkowski, Ireneusz; Nowak, Jan K.; Karnowski, Karol; Zebryk, Paweł; Puszczewicz, Mariusz; Walkowiak, Jaroslaw; Wojtkowski, Maciej
Quantitative assessment of oral mucosa and labial minor salivary glands in patients with Sjögren’s syndrome using swept source OCT Journal Article
In: Biomedical Optics Express, 5 (1), pp. 259-274, 2013, ISSN: 2156-7085.
@article{nokey,
title = {Quantitative assessment of oral mucosa and labial minor salivary glands in patients with Sjögren’s syndrome using swept source OCT},
author = {Ireneusz Grulkowski and Jan K. Nowak and Karol Karnowski and Paweł Zebryk and Mariusz Puszczewicz and Jaroslaw Walkowiak and Maciej Wojtkowski},
doi = {10.1364/BOE.5.000259},
issn = {2156-7085},
year = {2013},
date = {2013-12-16},
journal = {Biomedical Optics Express},
volume = {5},
number = {1},
pages = {259-274},
abstract = {Three-dimensional imaging of the mucosa of the lower lip and labial minor salivary glands is demonstrated in vivo using swept source optical coherence tomography (OCT) system at 1310 nm with modified interface. Volumetric data sets of the inner surface of the lower lip covering ~230 mm2 field are obtained from patients with Sjögren’s syndrome and a control group. OCT enables high-resolution visualization of mucosal architecture using cross-sectional images as well as en-face projection images. Comprehensive morphometry of the labial minor salivary glands is performed, and statistical significance is assessed. Statistically significant differences in morphometric parameters are found when subgroups of patients with Sjögren’s syndrome are analyzed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Three-dimensional imaging of the mucosa of the lower lip and labial minor salivary glands is demonstrated in vivo using swept source optical coherence tomography (OCT) system at 1310 nm with modified interface. Volumetric data sets of the inner surface of the lower lip covering ~230 mm2 field are obtained from patients with Sjögren’s syndrome and a control group. OCT enables high-resolution visualization of mucosal architecture using cross-sectional images as well as en-face projection images. Comprehensive morphometry of the labial minor salivary glands is performed, and statistical significance is assessed. Statistically significant differences in morphometric parameters are found when subgroups of patients with Sjögren’s syndrome are analyzed.
2012
5.
Kennedy, Brendan F.; Wojtkowski, Maciej; Szkulmowski, Maciej; Kennedy, Kelsey M.; Karnowski, Karol; Sampson, David D.
Improved measurement of vibration amplitude in dynamic optical coherence elastography Journal Article
In: Biomedical Optics Express, 3 (12), pp. 3138-3152, 2012, ISSN: 2156-7085.
@article{nokey,
title = {Improved measurement of vibration amplitude in dynamic optical coherence elastography},
author = {Brendan F. Kennedy and Maciej Wojtkowski and Maciej Szkulmowski and Kelsey M. Kennedy and Karol Karnowski and David D. Sampson},
doi = {10.1364/BOE.3.003138},
issn = {2156-7085},
year = {2012},
date = {2012-11-07},
journal = {Biomedical Optics Express},
volume = {3},
number = {12},
pages = {3138-3152},
abstract = {Abstract: Optical coherence elastography employs optical coherence tomography (OCT) to measure the displacement of tissues under load and, thus, maps the resulting strain into an image, known as an elastogram. We present a new improved method to measure vibration amplitude in dynamic optical coherence elastography. The tissue vibration amplitude caused by sinusoidal loading is measured from the spread of the Doppler spectrum, which is extracted using joint spectral and time domain signal processing. At low OCT signal-to-noise ratio (SNR), the method provides more accurate vibration amplitude measurements than the currently used phase-sensitive method. For measurements performed on a mirror at OCT SNR = 5 dB, our method introduces <3% error, compared to >20% using the phase-sensitive method. We present elastograms of a tissue-mimicking phantom and excised porcine tissue that demonstrate improvements, including a 50% increase in the depth range of reliable vibration amplitude measurement.
},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract: Optical coherence elastography employs optical coherence tomography (OCT) to measure the displacement of tissues under load and, thus, maps the resulting strain into an image, known as an elastogram. We present a new improved method to measure vibration amplitude in dynamic optical coherence elastography. The tissue vibration amplitude caused by sinusoidal loading is measured from the spread of the Doppler spectrum, which is extracted using joint spectral and time domain signal processing. At low OCT signal-to-noise ratio (SNR), the method provides more accurate vibration amplitude measurements than the currently used phase-sensitive method. For measurements performed on a mirror at OCT SNR = 5 dB, our method introduces <3% error, compared to >20% using the phase-sensitive method. We present elastograms of a tissue-mimicking phantom and excised porcine tissue that demonstrate improvements, including a 50% increase in the depth range of reliable vibration amplitude measurement.
2011
4.
Karnowski, Karol; Kaluzny, Bartlomiej J.; Szkulmowski, Maciej; Gora, Michalina; Wojtkowski, Maciej
Corneal topography with high-speed swept source OCT in clinical examination Journal Article
In: Biomedical Optics Express, 2 (9), pp. 2709-2720, 2011, ISSN: 2156-7085.
@article{nokey,
title = {Corneal topography with high-speed swept source OCT in clinical examination},
author = {Karol Karnowski and Bartlomiej J. Kaluzny and Maciej Szkulmowski and Michalina Gora and Maciej Wojtkowski
},
doi = {10.1364/BOE.2.002709},
issn = {2156-7085},
year = {2011},
date = {2011-08-29},
journal = {Biomedical Optics Express},
volume = {2},
number = {9},
pages = {2709-2720},
abstract = {We present the applicability of high-speed swept source (SS) optical coherence tomography (OCT) for quantitative evaluation of the corneal topography. A high-speed OCT device of 108,000 lines/s permits dense 3D imaging of the anterior segment within a time period of less than one fourth of second, minimizing the influence of motion artifacts on final images and topographic analysis. The swept laser performance was specially adapted to meet imaging depth requirements. For the first time to our knowledge the results of a quantitative corneal analysis based on SS OCT for clinical pathologies such as keratoconus, a cornea with superficial postinfectious scar, and a cornea 5 months after penetrating keratoplasty are presented. Additionally, a comparison with widely used commercial systems, a Placido-based topographer and a Scheimpflug imaging-based topographer, is demonstrated.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present the applicability of high-speed swept source (SS) optical coherence tomography (OCT) for quantitative evaluation of the corneal topography. A high-speed OCT device of 108,000 lines/s permits dense 3D imaging of the anterior segment within a time period of less than one fourth of second, minimizing the influence of motion artifacts on final images and topographic analysis. The swept laser performance was specially adapted to meet imaging depth requirements. For the first time to our knowledge the results of a quantitative corneal analysis based on SS OCT for clinical pathologies such as keratoconus, a cornea with superficial postinfectious scar, and a cornea 5 months after penetrating keratoplasty are presented. Additionally, a comparison with widely used commercial systems, a Placido-based topographer and a Scheimpflug imaging-based topographer, is demonstrated.
3.
Alonso-Caneiro, David; Karnowski, Karol; Kaluzny, Bartlomiej J.; Kowalczyk, Andrzej; Wojtkowski, Maciej
Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system Journal Article
In: Optics Express, 19 (15), pp. 14188-14199, 2011, ISSN: 1094-4087.
@article{nokey,
title = {Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system},
author = {David Alonso-Caneiro and Karol Karnowski and Bartlomiej J. Kaluzny and Andrzej Kowalczyk and Maciej Wojtkowski},
doi = {10.1364/OE.19.014188},
issn = {1094-4087},
year = {2011},
date = {2011-07-11},
journal = {Optics Express},
volume = {19},
number = {15},
pages = {14188-14199},
abstract = {We present a novel method and instrument for in vivo imaging and measurement of the human corneal dynamics during an air puff. The instrument is based on high-speed swept source optical coherence tomography (ssOCT) combined with a custom adapted air puff chamber from a non-contact tonometer, which uses an air stream to deform the cornea in a non-invasive manner. During the short period of time that the deformation takes place, the ssOCT acquires multiple A-scans in time (M-scan) at the center of the air puff, allowing observation of the dynamics of the anterior and posterior corneal surfaces as well as the anterior lens surface. The dynamics of the measurement are driven by the biomechanical properties of the human eye as well as its intraocular pressure. Thus, the analysis of the M-scan may provide useful information about the biomechanical behavior of the anterior segment during the applanation caused by the air puff. An initial set of controlled clinical experiments are shown to comprehend the performance of the instrument and its potential applicability to further understand the eye biomechanics and intraocular pressure measurements. Limitations and possibilities of the new apparatus are discussed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present a novel method and instrument for in vivo imaging and measurement of the human corneal dynamics during an air puff. The instrument is based on high-speed swept source optical coherence tomography (ssOCT) combined with a custom adapted air puff chamber from a non-contact tonometer, which uses an air stream to deform the cornea in a non-invasive manner. During the short period of time that the deformation takes place, the ssOCT acquires multiple A-scans in time (M-scan) at the center of the air puff, allowing observation of the dynamics of the anterior and posterior corneal surfaces as well as the anterior lens surface. The dynamics of the measurement are driven by the biomechanical properties of the human eye as well as its intraocular pressure. Thus, the analysis of the M-scan may provide useful information about the biomechanical behavior of the anterior segment during the applanation caused by the air puff. An initial set of controlled clinical experiments are shown to comprehend the performance of the instrument and its potential applicability to further understand the eye biomechanics and intraocular pressure measurements. Limitations and possibilities of the new apparatus are discussed.
2010
2.
Kaluzny, Bartlomiej J; Gora, Michalina; Karnowski, Karol; Grulkowski, Ireneusz; Kowalczyk, Andrzej; Wojtkowski, Maciej
Imaging of the Lens Capsule with an Ultrahigh Resolution Spectral Optical Coherence Tomography Prototype Based on a Femtosecond Laser Journal Article
In: British Journal of Ophthalmology, 94 , 2010, ISSN: 0007-1161.
@article{nokey,
title = {Imaging of the Lens Capsule with an Ultrahigh Resolution Spectral Optical Coherence Tomography Prototype Based on a Femtosecond Laser},
author = {Bartlomiej J Kaluzny and Michalina Gora and Karol Karnowski and Ireneusz Grulkowski and Andrzej Kowalczyk and Maciej Wojtkowski},
doi = {10.1136/bjo.2008.155879},
issn = {0007-1161},
year = {2010},
date = {2010-03-09},
journal = {British Journal of Ophthalmology},
volume = {94},
abstract = {To demonstrate the applicability of ultrahigh-speed, ultrahigh-resolution spectral optical coherence tomography (SOCT) to cross-sectional imaging of the capsular bag in vivo.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
To demonstrate the applicability of ultrahigh-speed, ultrahigh-resolution spectral optical coherence tomography (SOCT) to cross-sectional imaging of the capsular bag in vivo.
2009
1.
Gora, Michalina; Karnowski, Karol; Szkulmowski, Maciej; Kaluzny, Bartlomiej J.; Huber, Robert; Kowalczyk, Andrzej; Wojtkowski, Maciej
Ultra-high-speed swept source OCT imaging of the anterior segment of human eye at 200 kHz with adjustable imaging range Journal Article
In: Optics Express, 17 (17), pp. 14880-14894, 2009, ISSN: 1094-4087.
@article{nokey,
title = {Ultra-high-speed swept source OCT imaging of the anterior segment of human eye at 200 kHz with adjustable imaging range},
author = {Michalina Gora and Karol Karnowski and Maciej Szkulmowski and Bartlomiej J. Kaluzny and Robert Huber and Andrzej Kowalczyk and Maciej Wojtkowski},
doi = {10.1364/OE.17.014880},
issn = {1094-4087},
year = {2009},
date = {2009-08-06},
urldate = {2009-08-06},
journal = {Optics Express},
volume = {17},
number = {17},
pages = {14880-14894},
abstract = {We present an application of in vivo anterior segment imaging of the human eye with an ultrahigh speed swept source OCT instrument. For this purpose, a dedicated OCT system was designed and constructed. This instrument enables axial zooming by automatic reconfiguration of spectral sweep range; an enhanced imaging range mode enables imaging of the entire anterior segment while a high axial resolution mode provides detailed morphological information of the chamber angle and the cornea. The speed of 200,000 lines/s enables high sampling density in three-dimensional imaging of the entire cornea in 250 ms promising future applications of OCT for optical corneal topography, pachymetry and elevation maps. The results of a preliminary quantitative corneal analysis based on OCT data free form motion artifacts are presented. Additionally, a volumetric and real time reconstruction of dynamic processes, like pupillary reaction to light stimulus or blink-induced contact lens movements are demonstrated.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present an application of in vivo anterior segment imaging of the human eye with an ultrahigh speed swept source OCT instrument. For this purpose, a dedicated OCT system was designed and constructed. This instrument enables axial zooming by automatic reconfiguration of spectral sweep range; an enhanced imaging range mode enables imaging of the entire anterior segment while a high axial resolution mode provides detailed morphological information of the chamber angle and the cornea. The speed of 200,000 lines/s enables high sampling density in three-dimensional imaging of the entire cornea in 250 ms promising future applications of OCT for optical corneal topography, pachymetry and elevation maps. The results of a preliminary quantitative corneal analysis based on OCT data free form motion artifacts are presented. Additionally, a volumetric and real time reconstruction of dynamic processes, like pupillary reaction to light stimulus or blink-induced contact lens movements are demonstrated.