ORCID Profile
0000-0003-4782-0498
Current Organisation
University of Western Australia
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Biomedical Instrumentation | Optical Physics | Optical Physics not elsewhere classified | Analytical Chemistry | Pharmacology and Pharmaceutical Sciences | Biomaterials | Sensor Technology (Chemical aspects) | Immunological and Bioassay Methods | Pharmaceutical Sciences | Regenerative Medicine (incl. Stem Cells and Tissue Engineering) | Nanobiotechnology |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Biological Sciences | Human Pharmaceutical Treatments (e.g. Antibiotics) | Skeletal System and Disorders (incl. Arthritis) | Scientific Instruments | Clinical Health (Organs, Diseases and Abnormal Conditions) not elsewhere classified | Expanding Knowledge in the Information and Computing Sciences | Human Biological Preventatives (e.g. Vaccines) | Human Diagnostics | Expanding Knowledge in Technology
Related Links
Publications
Optical Coherence Elastography Applications
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_009
Abstract: In this chapter, we describe the applications proposed for optical coherence elastography (OCE), paying particular attention to applications in oncology, ophthalmology, and tissue engineering. In addition, we briefly describe proposed applications in areas such as cardiology, dermatology, and pulmonology. As well as describing the potential for OCE in each of these areas, and studies performed to date, we describe the challenges, and opportunities that may lie ahead in each area. We also describe some important considerations when commencing collaborations that are focused on applying OCE in new areas.
Speckle in Optical Coherence Tomography
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_004
Abstract: Speckle is a characteristic granular texture inherent to optical coherence tomography (OCT) images of turbid media, such as biological tissues. Speckle is a consequence of the coherent nature of OCT, and results from the interference of light scattered by sub-resolution scatterers. As deformation can rearrange these scatterers, consequently changing the realization of speckle, an understanding of speckle is required to understand elastogram formation in optical coherence elastography (OCE). In this chapter, we analyze speckle using both 1D and 3D models of OCT image formation, and we use these models to describe key concepts, including statistics of the OCT litude, intensity, and phase speckle size and speckle contrast. The chapter concludes with a description of techniques developed to reduce speckle contrast, including digital image processing, and speckle-modulation techniques.
Optical Coherence Tomography
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_003
Abstract: Optical coherence tomography (OCT) is an imaging technique that uses low-coherence interferometry to construct 3D images with micrometer-scale resolution. It is the imaging modality used in optical coherence elastography (OCE) to measure s le deformation as such, a detailed analysis of OCT is required to gain a clear understanding of OCE. This chapter provides an overview of the physical principles of OCT, including wave optics, coherence, and interferometry. This theory is then used to describe the main variants of OCT: time-domain OCT and Fourier-domain OCT the latter of which can be further sub ided into swept-source OCT and spectral-domain OCT. The relationship between system parameters (such as resolution, field of view, and signal-to-noise ratio), and the specification of OCT system components (such as the light source, objectives lens, and scanning mirrors) is also discussed. The chapter concludes with a brief description of OCT variants, including optical coherence microscopy, full-field OCT, and line-field OCT.
Tissue Mechanics
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_002
Abstract: The mechanics of tissue are exceptionally complex. They reflect the erse composition and architecture of many tissues, and have a profound role in regulating a multitude of biochemical and molecular processes. As a consequence, the understanding and quantification of tissue mechanics has been, and still remains, an important century-long pursuit. A main challenge in this area is the formalization of biological complexity into mathematical relations that are at once simple, as to be readily interpretable, and accurate, such that they confer key information on a broad variety of tissues. In elastography, as well as in many other mechanical imaging and metrology methods, this challenge is often approached by codifying tissue mechanics using the principles of continuum mechanics. There, the biological complexity is distilled to a few relations by using assumptions that are motivated by the composition, and observed behavior of tissues, as well as the measurement method used. In this chapter, we describe and reconcile this close relationship between the tissue biology, the measurement method, and the continuum mechanics models used to quantify measurements in elastography. Specifically, we focus on those principles that have founded many of the compelling demonstrations of optical coherence elastography.
Volumetric quantitative optical coherence elastography with an iterative inversion method
Publisher: The Optical Society
Date: 03-01-2019
Introduction to Optical Coherence Elastography
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_001
Abstract: Optical coherence elastography (OCE) is an emerging variant of elastography, based on optical coherence tomography (OCT) that provides microscale resolution to depths of several millimeters in dense tissue. OCE was first proposed in 1998 but has undergone extensive development only in the past ten years. Several implementations of OCE are now approaching technical maturity, and initial clinical studies have demonstrated its potential in a number of clinical applications, particularly in ophthalmology, oncology, and cardiology. In this chapter, we provide context for the development of OCE by first describing the clinical basis for elastography, and providing an overview of ultrasound elastography and magnetic resonance elastography, both of which are mature elastography techniques routinely deployed in clinical medicine. We then introduce various optical elastography techniques that have been developed in parallel with OCE, e.g., laser speckle elastography and Brillouin microscopy. Finally, we provide an introductory description of OCE as a precursor to more detailed analyses in subsequent chapters.
Tension-Based Optical Coherence Elastography: Mapping the Micro-Scale Strain Tensor Resulting From Tensile Loading
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2023
Computational optical palpation: a finite-element approach to micro-scale tactile imaging using a compliant sensor
Publisher: The Royal Society
Date: 03-2017
Abstract: High-resolution tactile imaging, superior to the sense of touch, has potential for future biomedical applications such as robotic surgery. In this paper, we propose a tactile imaging method, termed computational optical palpation, based on measuring the change in thickness of a thin, compliant layer with optical coherence tomography and calculating tactile stress using finite-element analysis. We demonstrate our method on test targets and on freshly excised human breast fibroadenoma, demonstrating a resolution of up to 15–25 µm and a field of view of up to 7 mm. Our method is open source and readily adaptable to other imaging modalities, such as ultrasonography and confocal microscopy.
Optical coherence elastography for cellular-scale stiffness imaging of mouse aorta
Publisher: SPIE
Date: 29-04-2017
DOI: 10.1117/12.2269903
Analysis of friction in quantitative micro-elastography
Publisher: Optica Publishing Group
Date: 11-09-2023
DOI: 10.1364/BOE.494013
Compression Optical Coherence Elastography
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_007
Abstract: Compression optical coherence elastography (OCE) is a variant of OCE that maps mechanical parameters, or properties of a s le by measuring the deformation in response to quasi-static compressive loading. Relative to other OCE techniques, to date, compression OCE has provided higher acquisition speed, and the capability to scan over wider fields of view. In early compression OCE studies, it was not possible to estimate quantitative mechanical properties, such as elasticity, instead these early studies calculated qualitative mechanical parameters, typically strain. More recently, quantitative compression OCE has been developed to enable the estimation of elasticity, extending its use to broader applications. However, physical contact between the s le, and loading mechanism is typically required, which is a drawback in applications involving delicate tissues, such as ophthalmology. This chapter focuses on the technical development of compression OCE, beginning with the mechanical model used to determine elasticity. An overview of methods for estimating mechanical parameters, and properties in particular, strain, stress, and elasticity, is provided. In addition, image quality metrics defined to characterize the imaging performance, such as spatial resolution, and sensitivity, are described.
Optical Coherence Elastography Techniques
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_006
Abstract: Tissue mechanical properties determine the relationship between an applied mechanical load and the resulting deformation of the s le. In optical coherence elastography (OCE), the objective is to spatially resolve tissue mechanical properties from often incomplete and noisy measurements of the load and deformation. This is achieved by solving an inverse problem, using a model of elasticity that reasonably describes the behavior of tissue. Incorporating more parameters into the model (such as heterogeneity, anisotropy, nonlinearity, or viscoelasticity) than are needed in a given application can unnecessarily complicate the inverse problem. Also, how the load is applied can enhance certain tissue responses, and the validity of an elasticity model, and, thus, allow for the characterization of tissue in different regimes. A successful OCE technique offers a good match between the load application method, and the tissue mechanical properties of interest, and employs a reasonably complete but simplified mechanical model that provides a noise-robust inversion. OCE techniques can be classified into two broad categories: those inducing and subsequently tracking propagating mechanical waves, and those applying and assuming a uniaxial load, and tracking the deformation in response. With a brief introduction to the former, this chapter focuses on the latter group, describes the most prominent of these techniques, and presents an overview of studies that have successfully extracted mechanical properties in tissue-like media.
Fibrin phantom for use in optical coherence tomography
Publisher: SPIE-Intl Soc Optical Eng
Date: 2010
DOI: 10.1117/1.3427249
Abstract: This work presents a novel tissue-mimicking phantom for use in a range of optical coherence tomography (OCT) experiments. Such phantoms are critical in the development and assessment of new OCT techniques, but no previously published phantoms have become universally accepted. We present the first description of a phantom based on a fibrin matrix, which improves key attributes of previously published methods. It provides a biocompatible, optically transparent scaffold in which to incorporate organic and/or inorganic optical scattering materials. Its fabrication time is markedly shorter than many common phantoms, and its lifetime is longer than other biocompatible phantoms. The potential of fibrin phantoms incorporating Intralipid() to introduce uniform optical scattering is demonstrated. The measured attenuation coefficient as a function of Intralipid concentration confirms the ability to control optical scattering. A bilayer phantom with distinct optical scattering in each layer is also presented.
In vivo dynamic optical coherence elastography using a ring actuator
Publisher: Optica Publishing Group
Date: 12-11-2009
DOI: 10.1364/OE.17.021762
Measuring Deformation in Optical Coherence Elastography
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_005
Abstract: Deformation is the change in size and shape of a s le in response to an applied load. Accurately measuring deformation is critical in optical coherence elastography (OCE), as along with the validity of the mechanical model of the s le, it determines the accuracy of the measurement of mechanical properties. In this chapter, we describe prominent methods to measure deformation in OCE, including phase-sensitive detection and cross-correlation-based approaches such as speckle tracking. We describe the working principles of these methods and analyze their advantages and disadvantages in the context of performance metrics including sensitivity, accuracy, and spatial resolution. In addition, we briefly describe several less prominent methods such as morphological tracking, correlation stability, digitally shifted complex cross-correlation, and Doppler spectrum detection.
A Novel, Reliable Protocol to Objectively Assess Scar Stiffness Using Shear Wave Elastography
Publisher: Elsevier BV
Date: 07-2020
Strain and elasticity imaging in compression optical coherence elastography
Publisher: No publisher found
Date: 2021
Supplementary Data from Quantitative Micro-Elastography Enables In Vivo Detection of Residual Cancer in the Surgical Cavity during Breast-Conserving Surgery
Publisher: American Association for Cancer Research (AACR)
Date: 31-03-2023
DOI: 10.1158/0008-5472.22431891
Abstract: Supplementary Data from Quantitative Micro-Elastography Enables i In Vivo /i Detection of Residual Cancer in the Surgical Cavity during Breast-Conserving Surgery
Parametric imaging of viscoelasticity using optical coherence elastography
Publisher: IOP Publishing
Date: 26-02-2015
DOI: 10.1088/0031-9155/60/6/2293
Abstract: We demonstrate imaging of soft tissue viscoelasticity using optical coherence elastography. Viscoelastic creep deformation is induced in tissue using step-like compressive loading and the resulting time-varying deformation is measured using phase-sensitive optical coherence tomography. From a series of co-located B-scans, we estimate the local strain rate as a function of time, and parameterize it using a four-parameter Kelvin-Voigt model of viscoelastic creep. The estimated viscoelastic strain and time constant are used to visualize viscoelastic creep in 2D, dual-parameter viscoelastograms. We demonstrate our technique on six silicone tissue-simulating phantoms spanning a range of viscoelastic parameters. As an ex le in soft tissue, we report viscoelastic contrast between muscle and connective tissue in fresh, ex vivo rat gastrocnemius muscle and mouse abdominal transection. Imaging viscoelastic creep deformation has the potential to provide complementary contrast to existing imaging modalities, and may provide greater insight into disease pathology.
Enhancing Resistance of Silk Fibroin Material to Enzymatic Degradation by Cross-Linking Both Crystalline and Amorphous Domains
Publisher: American Chemical Society (ACS)
Date: 05-02-2020
Three‐dimensional mapping of the attenuation coefficient in optical coherence tomography to enhance breast tissue microarchitecture contrast
Publisher: Wiley
Date: 20-03-2020
Modelling the co-firing of coal and biomass in a 10 kWth oxy-fuel fluidized bed
Publisher: Elsevier BV
Date: 2022
Simplifying the assessment of human breast cancer by mapping a micro‐scale heterogeneity index in optical coherence elastography
Publisher: Wiley
Date: 12-09-2016
Abstract: Surgical treatment of breast cancer aims to identify and remove all malignant tissue. Intraoperative assessment of tumor margins is, however, not exact thus, re-excision is frequently needed, or excess normal tissue is removed. Imaging methods applicable intraoperatively could help to reduce re-excision rates whilst minimizing removal of excess healthy tissue. Optical coherence elastography (OCE) has been proposed for use in breast-conserving surgery however, intraoperative interpretation of complex OCE images may prove challenging. Observations of breast cancer on multiple length scales, by OCE, ultrasound elastography, and atomic force microscopy, have shown an increase in the mechanical heterogeneity of malignant breast tumors compared to normal breast tissue. In this study, a micro-scale mechanical heterogeneity index is introduced and used to form heterogeneity maps from OCE scans of 10 ex vivo human breast tissue s les. Through comparison of OCE, optical coherence tomography images, and corresponding histology, malignant tissue is shown to possess a higher heterogeneity index than benign tissue. The heterogeneity map simplifies the contrast between tumor and normal stroma in breast tissue, facilitating the rapid identification of possible areas of malignancy, which is an important step towards intraoperative margin assessment using OCE.
Speckle reduction in optical coherence tomography images using tissue viscoelasticity
Publisher: SPIE-Intl Soc Optical Eng
Date: 2011
DOI: 10.1117/1.3548239
Abstract: We present a technique to reduce speckle in optical coherence tomography images of soft tissues. An average is formed over a set of B-scans that have been decorrelated by viscoelastic creep strain. The necessary correction for the deformation-induced spatial distortions between B-scans is achieved through geometrical co-registration using an affine transformation. Speckle reduction by up to a factor of 1.65 is shown in images of tissue-mimicking soft fibrin phantoms and excised human lymph node tissue with no observable loss of spatial resolution.
Speckle-dependent accuracy in phase-sensitive optical coherence tomography
Publisher: Optica Publishing Group
Date: 17-05-2021
DOI: 10.1364/OE.417954
Abstract: Phase-sensitive optical coherence tomography (OCT) is used to measure motion in a range of techniques, such as Doppler OCT and optical coherence elastography (OCE). In phase-sensitive OCT, motion is typically estimated using a model of the OCT signal derived from a single reflector. However, this approach is not representative of turbid s les, such as tissue, which exhibit speckle. In this study, for the first time, we demonstrate, through theory and experiment that speckle significantly lowers the accuracy of phase-sensitive OCT in a manner not accounted for by the OCT signal-to-noise ratio (SNR). We describe how the inaccuracy in speckle reduces phase difference sensitivity and introduce a new metric, speckle brightness, to quantify the amount of constructive interference at a given location in an OCT image. Experimental measurements show an almost three-fold degradation in sensitivity between regions of high and low speckle brightness at a constant OCT SNR. Finally, we apply these new results in compression OCE to demonstrate a ten-fold improvement in strain sensitivity, and a five-fold improvement in contrast-to-noise by incorporating independent speckle realizations. Our results show that speckle introduces a limit to the accuracy of phase-sensitive OCT and that speckle brightness should be considered to avoid erroneous interpretation of experimental data.
Pulse Pedestal Suppression Using Four-Wave Mixing in an SOA
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2008
Finger-mounted quantitative micro-elastography
Publisher: The Optical Society
Date: 11-03-2019
Polarization Dependent Intra-Band Dynamics in Semiconductor Optical Amplifiers
Publisher: IEEE
Date: 07-2007
Wide-field quantitative micro-elastography of human breast tissue
Publisher: The Optical Society
Date: 09-02-2018
DOI: 10.1364/BOE.9.001082
Outlook
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_011
Abstract: In this chapter, we provide perspectives on the current stage of, and likely future directions for, optical coherence elastography (OCE) development using the framework introduced in Chap. 10. We describe corresponding developments in ultrasound elastography and optical coherence tomography (OCT), and use these precedents as indicators for what may be required for successful translation of OCE to routine use in intended operational environments. We suggest areas for future technical refinement, describe feasibility studies performed so far, and provide perspectives on the clinical validation and commercialization of OCE.
Optical Coherence Elastography Imaging Probes
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
DOI: 10.1063/9780735423664_010
Abstract: Imaging probes for optical coherence elastography (OCE) are undergoing development to enable its practical implementation in a number of applications. The specific challenges posed by each application defines the technical requirements for each probe, leading to the development of a range of benchtop, handheld and endoscopic probes. In addition, a number of more compact OCE imaging probes have been proposed, including finger-mounted and needle-based probes. In this chapter, we describe each of these probes in detail within the context of the relevant applications they are proposed for. An analysis of each probe is provided, with particular focus on optical design, mechanical loading, and image acquisition protocol.
Biomechanical assessment of chronic liver injury using quantitative micro-elastography
Publisher: Optica Publishing Group
Date: 09-2022
DOI: 10.1364/BOE.467684
Abstract: Hepatocellular carcinoma is one of the most lethal cancers worldwide, causing almost 700,000 deaths annually. It mainly arises from cirrhosis, which, in turn, results from chronic injury to liver cells and corresponding fibrotic changes. Although it is known that chronic liver injury increases the elasticity of liver tissue, the role of increased elasticity of the microenvironment as a possible hepatocarcinogen is yet to be investigated. One reason for this is the paucity of imaging techniques capable of mapping the micro-scale elasticity variation in liver and correlating that with cancerous mechanisms on the cellular scale. The clinical techniques of ultrasound elastography and magnetic resonance elastography typically do not provide micro-scale resolution, while atomic force microscopy can only assess the elasticity of a limited number of cells. We propose quantitative micro-elastography (QME) for mapping the micro-scale elasticity of liver tissue into images known as micro-elastograms, and therefore, as a technique capable of correlating the micro-environment elasticity of tissue with cellular scale cancerous mechanisms in liver. We performed QME on 13 freshly excised healthy and diseased mouse livers and present micro-elastograms, together with co-registered histology, in four representative cases. Our results indicate a significant increase in the mean (×6.3) and standard deviation (×6.0) of elasticity caused by chronic liver injury and demonstrate that the onset and progression of pathological features such as fibrosis, hepatocyte damage, and immune cell infiltration correlate with localized variations in micro-elastograms.
Ultrahigh-resolution optical coherence elastography
Publisher: The Optical Society
Date: 16-12-2015
DOI: 10.1364/OL.41.000021
Detuning dependence of four-wave mixing between picosecond pulses in a multi-quantum well semiconductor optical amplifier
Publisher: IEEE
Date: 2007
Experimental Investigation of Polarization Effects in Semiconductor Optical Amplifiers and Implications for All-Optical Switching
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2008
Front Matter
Publisher: AIP Publishing
Date: 2021
Handheld volumetric manual compression-based quantitative microelastography
Publisher: Wiley
Date: 27-02-2020
Smartphone-based optical palpation
Publisher: Optica Publishing Group
Date: 06-05-2021
DOI: 10.1364/BOE.424567
Abstract: Smartphones are now integral to many telehealth services that provide remote patients with an improved diagnostic standard of care. The ongoing management of burn wounds and scars is one area in which telehealth has been adopted, using video and photography to assess the repair process over time. However, a current limitation is the inability to evaluate scar stiffness objectively and repeatedly: an essential measurement for classifying the degree of inflammation and fibrosis. Optical elastography detects mechanical contrast on a micrometer- to millimeter-scale, however, typically requires expensive optics and bulky imaging systems, making it prohibitive for wide-spread adoption in telehealth. More recently, a new variant of optical elastography, camera-based optical palpation, has demonstrated the capability to perform elastography at low cost using a standard digital camera. In this paper, we propose smartphone-based optical palpation, adapting camera-based optical palpation by utilizing a commercially available smartphone camera to provide sub-millimeter resolution imaging of mechanical contrast in scar tissue in a form factor that is amenable to telehealth. We first validate this technique on a silicone phantom containing a 5 × 5 × 1 mm 3 embedded inclusion, demonstrating comparative image quality between mounted and handheld implementations. We then demonstrate preliminary in vivo smartphone-based optical palpation by imaging a region of healthy skin and two scars on a burns patient, showing clear mechanical contrast between regions of scar tissue and healthy tissue. This study represents the first implementation of elastography on a smartphone device, extending the potential application of elastography to telehealth.
Microscale imaging of breast tumor margins using optical coherence elastography
Publisher: SPIE-Intl Soc Optical Eng
Date: 05-2017
Evaluating distribution of foveal avascular zone parameters corrected by lateral magnification, and their associations with retinal thickness
Publisher: Elsevier BV
Date: 06-2022
Camera-based optical palpation
Publisher: Springer Science and Business Media LLC
Date: 29-09-2020
DOI: 10.1038/S41598-020-72603-5
Abstract: Optical elastography is undergoing extensive development as an imaging tool to map mechanical contrast in tissue. Here, we present a new platform for optical elastography by generating sub-millimetre-scale mechanical contrast from a simple digital camera. This cost-effective, compact and easy-to-implement approach opens the possibility to greatly expand applications of optical elastography both within and beyond the field of medical imaging. Camera-based optical palpation (CBOP) utilises a digital camera to acquire photographs that quantify the light intensity transmitted through a silicone layer comprising a dense distribution of micro-pores (diameter, 30–100 µm). As the transmission of light through the micro-pores increases with compression, we deduce strain in the layer directly from intensity in the digital photograph. By pre-characterising the relationship between stress and strain of the layer, the measured strain map can be converted to an optical palpogram, a map of stress that visualises mechanical contrast in the s le. We demonstrate a spatial resolution as high as 290 µm in CBOP, comparable to that achieved using an optical coherence tomography-based implementation of optical palpation. In this paper, we describe the fabrication of the micro-porous layer and present experimental results from structured phantoms containing stiff inclusions as small as 0.5 × 0.5 × 1 mm. In each case, we demonstrate high contrast between the inclusion and the base material and validate both the contrast and spatial resolution achieved using finite element modelling. By performing CBOP on freshly excised human breast tissue, we demonstrate the capability to delineate tumour from surrounding benign tissue.
Experimental analysis of polarization dependence of ultrafast gain dynamics in SOAs
Publisher: SPIE
Date: 03-06-2005
DOI: 10.1117/12.605043
In Situ Characterization of Melt–Electrowritten Scaffolds in 3D Using Optical Coherence Tomography
Publisher: Wiley
Date: 03-2022
Abstract: Recent developments in melt electrowriting (MEW), a high‐resolution additive manufacturing technology, have led to increases in scaffold complexity. However, MEW scaffolds are currently characterized ex situ, which causes time–consuming iterations of characterization and fabrication that limit scaffold throughput and more widespread use of the technology. For the first time, an in situ method to characterize the 3D microstructure of MEW scaffolds using optical coherence tomography (OCT) is described. Calculations of microstructural features are performed on OCT data using a custom algorithm, demonstrating close correspondence with scanning electron microscopy (SEM). For ex le, OCT calculations of fiber diameter and scaffold thickness are within an average of 0.31 and 1.79 μm, respectively, of corresponding SEM–derived calculations. Additionally, the 3D capabilities of OCT enable the nondestructive characterization of scaffolds with depth–varying microstructures, overcoming some main limitations of SEM. Finally, in situ characterization is achieved by integrating the OCT scanner within an MEW printer, enabling the scaffold microstructure to be evaluated and optimized during manufacture. This new capability represents an important step toward achieving an efficient fabrication–characterization cycle with the guaranteed scaffold quality and reproducibility required to validate the manufacturing process.
Numerical analysis of four-wave mixing between picosecond mode-locked laser pulses in a tensile-strained bulk SOA
Publisher: Springer Science and Business Media LLC
Date: 04-2008
Wavelength conversion using polarization rotation in a bulk semiconductor optical amplifier
Publisher: IEEE
Date: 2005
Analysis of image formation in optical coherence elastography using a multiphysics approach
Publisher: The Optical Society
Date: 08-2014
DOI: 10.1364/BOE.5.002913
Polarization dependence of non-linear gain compression factor in semiconductor optical amplifier
Publisher: Optica Publishing Group
Date: 28-05-2008
DOI: 10.1364/OE.16.008641
Abstract: We investigate the power and the polarization dependence of the intraband dynamics in a bulk semiconductor optical lifier using both a 2.5-ps pump-probe experimental set-up in contra-propagation and a theoretical model. Our model is based on the rate equations and takes into account the polarization dependence of the gain. By comparing experimental and computational results we are able to highlight the dependences of the intraband dynamics and to extract the non-linear gain compression factor as a function of both pulse energy and polarization of the injected pulses.
Investigation of optimum wavelength converter based on nonlinear polarisation rotation in a bulk SOA
Publisher: Institution of Engineering and Technology (IET)
Date: 04-2007
Biomedical device innovation methodology
Publisher: SPIE-Intl Soc Optical Eng
Date: 14-12-2018
Experimental investigation of polarisation rotation in semiconductor optical amplifiers
Publisher: Institution of Engineering and Technology (IET)
Date: 2004
Supplementary Data from Quantitative Micro-Elastography Enables In Vivo Detection of Residual Cancer in the Surgical Cavity during Breast-Conserving Surgery
Publisher: American Association for Cancer Research (AACR)
Date: 31-03-2023
DOI: 10.1158/0008-5472.22431891.V1
Abstract: Supplementary Data from Quantitative Micro-Elastography Enables i In Vivo /i Detection of Residual Cancer in the Surgical Cavity during Breast-Conserving Surgery
Optofluidic needle probe integrating targeted delivery of fluid with optical coherence tomography imaging
Publisher: The Optical Society
Date: 08-05-2014
DOI: 10.1364/OL.39.002888
A review of optical coherence tomography in breast cancer
Publisher: Walter de Gruyter GmbH
Date: 2014
Abstract: Optical coherence tomography (OCT) is a medical imaging modality that opens up new opportunities for imaging in breast cancer. It provides two- and three-dimensional micro-scale images of tissue structure from bulk tissue,
Analysis of strain estimation methods in phase-sensitive compression optical coherence elastography
Publisher: Optica Publishing Group
Date: 18-03-2022
DOI: 10.1364/BOE.447340
Abstract: In compression optical coherence elastography (OCE), deformation is quantified as the local strain at each pixel in the OCT field-of-view. A range of strain estimation methods have been demonstrated, yet it is unclear which method provides the best performance. Here, we analyze the two most prevalent strain estimation methods used in phase-sensitive compression OCE, i.e., weighted least squares (WLS) and the vector method. We introduce a framework to compare strain imaging metrics, incorporating strain sensitivity, strain signal-to-noise ratio (SNR), strain resolution, and strain accuracy. In addition, we propose a new phase unwrapping algorithm in OCE, fast phase unwrapping (FPU), and combine it with WLS, termed WLS FPU . Using the framework, we compare this new strain estimation method with both a current implementation of WLS that incorporates weighted phase unwrapping (WPU), termed WLS WPU , and the vector method. Our analysis reveals that the three methods provide similar strain sensitivity, strain SNR, and strain resolution, but that WLS FPU extends the dynamic range of accurate, measurable local strain, e.g., measuring a strain of 2.5 m ɛ with ∼4% error, that is ×11 and ×15 smaller than the error measured using WLS WPU and the vector method, respectively. We also demonstrate, for the first time, the capability to detect sub-resolution contrast in compression OCE, i.e. , changes in strain occurring within the strain axial resolution, and how this contrast varies between the different strain estimation methods. Lastly, we compare the performance of the three strain estimation methods on mouse skeletal muscle and human breast tissue and demonstrate that WLS FPU avoids strain imaging artifacts resulting from phase unwrapping errors in WLS WPU and provides improved contrast over the other two methods.
Investigation of SOA-based wavelength conversion at 80 Gb/s using bandpass filtering
Publisher: IEEE
Date: 2006
Subcellular mechano-microscopy: high resolution three-dimensional elasticity mapping using optical coherence microscopy
Publisher: Optica Publishing Group
Date: 27-06-2022
DOI: 10.1364/OL.451681
Abstract: The importance of cellular-scale mechanical properties is well-established, yet it is challenging to map subcellular elasticity in three dimensions. We present subcellular mechano-microscopy, an optical coherence microscopy (OCM)-based variant of three-dimensional (3-D) compression optical coherence elastography (OCE) that provides an elasticity system resolution of 5 × 5 × 5 µm: a 7-fold improvement in system resolution over previous OCE studies of cells. The improved resolution is achieved through a ∼5-fold improvement in optical resolution, refinement of the strain estimation algorithm, and demonstration that mechanical deformation of subcellular features provides feature resolution far greater than that demonstrated previously on larger features with diameter µm. We use mechano-microscopy to image adipose-derived stem cells encapsulated in gelatin methacryloyl. We compare our results with compression OCE and demonstrate that mechano-microscopy can provide contrast from subcellular features not visible using OCE.
The emergence of optical elastography in biomedicine
Publisher: Springer Science and Business Media LLC
Date: 04-2017
3D Volumetric Mechanosensation of MCF7 Breast Cancer Spheroids in a Linear Stiffness Gradient GelAGE
Publisher: Wiley
Date: 19-09-2023
Bioprinting silk fibroin using two-photon lithography enables control over the physico-chemical material properties and cellular response
Publisher: Elsevier BV
Date: 03-2022
Diagnostic accuracy of quantitative micro-elastography for margin assessment in breast-conserving surgery
Publisher: American Association for Cancer Research (AACR)
Date: 15-04-2020
DOI: 10.1158/0008-5472.CAN-19-1240
Abstract: An optical imaging technology probes breast tissue elasticity to provide accurate assessment of tumor margin involvement in breast-conserving surgery.
Optical palpation for the visualization of tumor in human breast tissue
Publisher: Wiley
Date: 30-08-2019
Abstract: Accurate and effective removal of tumor in one operation is an important goal of breast-conserving surgery. However, it is not always achieved. Surgeons often utilize manual palpation to assess the surgical margin and/or the breast cavity. Manual palpation, however, is subjective and has relatively low resolution. Here, we investigate a tactile imaging technique, optical palpation, for the visualization of tumor. Optical palpation generates maps of the stress at the surface of tissue under static preload compression. Stress is evaluated by measuring the deformation of a contacting thin compliant layer with known mechanical properties using optical coherence tomography. In this study, optical palpation is performed on 34 freshly excised human breast specimens. Wide field-of-view (up to ~46 × 46 mm) stress images, optical palpograms, are presented from four representative specimens, demonstrating the capability of optical palpation to visualize tumor. Median stress reported for adipose tissue, 4 kPa, and benign dense tissue, 8 kPa, is significantly lower than for invasive tumor, 60 kPa. In addition, we demonstrate that optical palpation provides contrast consistent with a related optical technique, quantitative micro-elastography. This study demonstrates that optical palpation holds promise for visualization of tumor in breast-conserving surgery.
Detection of multiple scattering in optical coherence tomography by speckle correlation of angle-dependent B-scans
Publisher: Optica Publishing Group
Date: 08-06-2010
DOI: 10.1364/OL.35.001998
Handheld optical palpation of turbid tissue with motion-artifact correction
Publisher: The Optical Society
Date: 18-12-2019
Structured three-dimensional optical phantom for optical coherence tomography
Publisher: The Optical Society
Date: 22-09-2011
DOI: 10.1364/OE.19.019480
Investigation of polarization dependent gain dynamics in a bulk SOA
Publisher: Elsevier BV
Date: 04-2007
Optical coherence tomography for longitudinal monitoring of vasculature in scars treated with laser fractionation
Publisher: Wiley
Date: 11-08-2016
Abstract: This study presents the first in vivo longitudinal assessment of scar vasculature in ablative fractional laser treatment using optical coherence tomography (OCT). A method based on OCT speckle decorrelation was developed to visualize and quantify the scar vasculature over the treatment period. Through reliable co-location of the imaging field of view across multiple imaging sessions, and compensation for motion artifact, the study was able to track the same scar tissue over a period of several months, and quantify changes in the vasculature area density. The results show incidences of occlusion of in idual vessels 3 days after the first treatment. The subsequent responses ˜20 weeks after the initial treatment show differences between immature and mature scars. Image analysis showed a distinct decrease (25 ± 13%, mean ± standard deviation) and increase (19 ± 5%) of vasculature area density for the immature and mature scars, respectively. This study establishes the feasibility of OCT imaging for quantitative longitudinal monitoring of vasculature in scar treatment. En face optical coherence tomography vasculature images pre-treatment (top) and ˜20 weeks after the first laser treatment (bottom) of a mature burn scar. Arrows mark the same vessel pattern.
Quantifying the influence of Bessel beams on image quality in optical coherence tomography
Publisher: Springer Science and Business Media LLC
Date: 24-03-2016
DOI: 10.1038/SREP23483
Abstract: Light scattered by turbid tissue is known to degrade optical coherence tomography (OCT) image contrast progressively with depth. Bessel beams have been proposed as an alternative to Gaussian beams to image deeper into turbid tissue. However, studies of turbid tissue comparing the image quality for different beam types are lacking. We present such a study, using numerically simulated beams and experimental OCT images formed by Bessel or Gaussian beams illuminating phantoms with optical properties spanning a range typical of soft tissue. We demonstrate that, for a given scattering parameter, the higher the scattering anisotropy the lower the OCT contrast, regardless of the beam type. When focusing both beams at the same depth in the s le, we show that, at focus and for equal input power and resolution, imaging with the Gaussian beam suffers less reduction of contrast. This suggests that, whilst Bessel beams offer extended depth of field in a single depth scan, for low numerical aperture (NA 0.1) and typical soft tissue properties (scattering coefficient, μ s = 3.7 mm −1 and high scattering anisotropy, g 0.95), superior contrast (by up to ~40%) may be obtained over an extended depth range by a Gaussian beam combined with dynamic focusing.
Optical Coherence Tomography of the Tympanic Membrane and Middle Ear: A Review
Publisher: Wiley
Date: 22-05-2018
Abstract: To evaluate the recent developments in optical coherence tomography (OCT) for tympanic membrane (TM) and middle ear (ME) imaging and to identify what further development is required for the technology to be integrated into common clinical use. PubMed, Embase, Google Scholar, Scopus, and Web of Science. A comprehensive literature search was performed for English language articles published from January 1966 to January 2018 with the keywords “tympanic membrane or middle ear,”“optical coherence tomography,” and “imaging.” Conventional imaging techniques cannot adequately resolve the microscale features of TM and ME, sometimes necessitating diagnostic exploratory surgery in challenging otologic pathology. As a high‐resolution noninvasive imaging technique, OCT offers promise as a diagnostic aid for otologic conditions, such as otitis media, cholesteatoma, and conductive hearing loss. Using OCT vibrometry to image the nanoscale vibrations of the TM and ME as they conduct acoustic waves may detect the location of ossicular chain dysfunction and differentiate between stapes fixation and incus‐stapes discontinuity. The capacity of OCT to image depth and thickness at high resolution allows 3‐dimensional volumetric reconstruction of the ME and has potential use for reconstructive tympanoplasty planning and the follow‐up of ossicular prostheses. To achieve common clinical use beyond these initial discoveries, future in vivo imaging devices must feature low‐cost probe or endoscopic designs and faster imaging speeds and demonstrate superior diagnostic utility to computed tomography and magnetic resonance imaging. While such technology has been available for OCT, its translation requires focused development through a close collaboration between engineers and clinicians.
In vivo characterisation of field pea stem wall thickness using optical coherence tomography
Publisher: Springer Science and Business Media LLC
Date: 11-10-2023
Stem cell migration and mechanotransduction on linear stiffness gradient hydrogels
Publisher: Proceedings of the National Academy of Sciences
Date: 15-05-2017
Abstract: Mechanobiology is receiving an increasing amount of focus, but the mechanics of cell-substrate behavior are often neglected in cell biology. As such, novel materials and systems that are simple to build and share in a nonengineering laboratory are sorely needed. We have fabricated gradient hydrogels with continuous linear gradients above and below the durotactic threshold, making it possible to pinpoint optimal stiffness values for a wide range of biological phenomena without the confounding effects of durotaxis. This system has the potential for wide adoption in the cell biology community because of its ease of fabrication, simple material ingredients, and wide gradient possibilities in a single well.
Automated quantification of lung structures from optical coherence tomography images
Publisher: The Optical Society
Date: 09-10-2013
DOI: 10.1364/BOE.4.002383
Ultrahigh resolution optical coherence elastography using a Bessel beam for extended depth of field
Publisher: SPIE
Date: 08-03-2016
DOI: 10.1117/12.2214684
Handheld probe for quantitative micro-elastography
Publisher: The Optical Society
Date: 16-07-2019
Three-dimensional mechanical characterization of murine skeletal muscle using quantitative micro-elastography
Publisher: Optica Publishing Group
Date: 17-10-2022
DOI: 10.1364/BOE.471062
Abstract: Skeletal muscle function is governed by both the mechanical and structural properties of its constituent tissues, which are both modified by disease. Characterizing the mechanical properties of skeletal muscle tissue at an intermediate scale, i.e. , between that of cells and organs, can provide insight into diseases such as muscular dystrophies. In this study, we use quantitative micro-elastography (QME) to characterize the micro-scale elasticity of ex vivo murine skeletal muscle in three-dimensions in whole muscles. To address the challenge of achieving high QME image quality with s les featuring uneven surfaces and geometry, we encapsulate the muscles in transparent hydrogels with flat surfaces. Using this method, we study aging and disease in quadriceps tissue by comparing normal wild-type (C57BL/6J) mice with dysferlin-deficient BLAJ mice, a model for the muscular dystrophy dysferlinopathy, at 3, 10, and 24 months of age (s le size of three per group). We observe a 77% decrease in elasticity at 24 months in dysferlin-deficient quadriceps compared to wild-type quadriceps.
Spectroscopic optical coherence elastography
Publisher: The Optical Society
Date: 22-11-2010
DOI: 10.1364/OE.18.025519
Establishing local manufacture of PPE for healthcare workers in the time of a global pandemic
Publisher: Elsevier BV
Date: 02-2023
Near Video-Rate Optical Coherence Elastography by Acceleration With a Graphics Processing Unit
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-08-2015
In vivo three-dimensional optical coherence elastography
Publisher: The Optical Society
Date: 23-03-2011
DOI: 10.1364/OE.19.006623
Multi-class classification of breast tissue using optical coherence tomography and attenuation imaging combined via deep learning
Publisher: Optica Publishing Group
Date: 12-05-2022
DOI: 10.1364/BOE.455110
Abstract: We demonstrate a convolutional neural network (CNN) for multi-class breast tissue classification as adipose tissue, benign dense tissue, or malignant tissue, using multi-channel optical coherence tomography (OCT) and attenuation images, and a novel Matthews correlation coefficient (MCC)-based loss function that correlates more strongly with performance metrics than the commonly used cross-entropy loss. We hypothesized that using multi-channel images would increase tumor detection performance compared to using OCT alone. 5,804 images from 29 patients were used to fine-tune a pre-trained ResNet-18 network. Adding attenuation images to OCT images yields statistically significant improvements in several performance metrics, including benign dense tissue sensitivity (68.0% versus 59.6%), malignant tissue positive predictive value (PPV) (79.4% versus 75.5%), and total accuracy (85.4% versus 83.3%), indicating that the additional contrast from attenuation imaging is most beneficial for distinguishing between benign dense tissue and malignant tissue.
Ultrahigh-Resolution Optical Coherence Elastography Images Cellular-Scale Stiffness of Mouse Aorta
Publisher: Elsevier BV
Date: 12-2017
Optical palpation for tumor margin assessment in breast-conserving surgery
Publisher: Optica Publishing Group
Date: 03-2021
DOI: 10.1364/BOE.415888
Abstract: Intraoperative margin assessment is needed to reduce the re-excision rate of breast-conserving surgery. One possibility is optical palpation, a tactile imaging technique that maps stress (force applied across the tissue surface) as an indicator of tissue stiffness. Images (optical palpograms) are generated by compressing a transparent silicone layer on the tissue and measuring the layer deformation using optical coherence tomography (OCT). This paper reports, for the first time, the diagnostic accuracy of optical palpation in identifying tumor within 1 mm of the excised specimen boundary using an automated classifier. Optical palpograms from 154 regions of interest (ROIs) from 71 excised tumor specimens were obtained. An automated classifier was constructed to predict the ROI margin status by first choosing a circle diameter, then searching for a location within the ROI where the circle was ≥ 75% filled with high stress (indicating a positive margin). A range of circle diameters and stress thresholds, as well as the impact of filtering out non-dense tissue regions, were tested. Sensitivity and specificity were calculated by comparing the automated classifier results with the true margin status, determined from co-registered histology. 83.3% sensitivity and 86.2% specificity were achieved, compared to 69.0% sensitivity and 79.0% specificity obtained with OCT alone on the same dataset using human readers. Representative optical palpograms show that positive margins containing a range of cancer types tend to exhibit higher stress compared to negative margins. These results demonstrate the potential of optical palpation for margin assessment.
Three-dimensional imaging of cell and extracellular matrix elasticity using quantitative micro-elastography
Publisher: Optica Publishing Group
Date: 14-01-2020
DOI: 10.1364/BOE.383419
Abstract: Recent studies in mechanobiology have revealed the importance of cellular and extracellular mechanical properties in regulating cellular function in normal and disease states. Although it is established that cells should be investigated in a three-dimensional (3-D) environment, most techniques available to study mechanical properties on the microscopic scale are unable to do so. In this study, for the first time, we present volumetric images of cellular and extracellular elasticity in 3-D biomaterials using quantitative micro-elastography (QME). We achieve this by developing a novel strain estimation algorithm based on 3-D linear regression to improve QME system resolution. We show that QME can reveal elevated elasticity surrounding human adipose-derived stem cells (ASCs) embedded in soft hydrogels. We observe, for the first time in 3-D, further elevation of extracellular elasticity around ASCs with overexpressed TAZ a mechanosensitive transcription factor which regulates cell volume. Our results demonstrate that QME has the potential to study the effects of extracellular mechanical properties on cellular functions in a 3-D micro-environment.
Optical Coherence Elastography
Publisher: AIP Publishing LLCMelville, New York
Date: 22-12-2021
Abstract: Optical Coherence Elastography: Imaging Tissue Mechanics on the Micro-Scale provides a unique and practical overview of this important new fi eld, which has seen tremendous growth in the last decade. Using optical coherence tomography (OCT) to measure s le deformation, optical coherence elastography (OCE) provides visualization of the three-dimensional, micro-scale mechanical properties of tissues and biomaterials and has shown distinct promise for application across clinical medicine, biology, and tissue engineering. This timely book provides:Detailed coverage of the key elements required for the successful implementation of OCE techniques, particularly OCT imaging, mechanical deformation, and image processingSynthesis of theory, methodology, and applications in one resourceDetailed discussion of the historical context within which OCE has evolved, particularly regarding ultrasound elastography and magnetic resonance elastographyPerspectives on likely future developments in OCE This book is an invaluable resource for graduate students and researchers in biophotonics and tissue engineering and for professionals working with OCT and elastography.
Numerical Analysis of Four-Wave Mixing between 2 ps mode-locked laser pulses in a Tensile-Strained Bulk SOA
Publisher: IEEE
Date: 09-2007
Analysis of sensitivity in quantitative micro-elastography
Publisher: Optica Publishing Group
Date: 03-2021
DOI: 10.1364/BOE.417829
Abstract: Quantitative micro-elastography (QME), a variant of compression optical coherence elastography (OCE), is a technique to image tissue elasticity on the microscale. QME has been proposed for a range of applications, most notably tumor margin assessment in breast-conserving surgery. However, QME sensitivity, a key imaging metric, has yet to be systematically analyzed. Consequently, it is difficult to optimize imaging performance and to assess the potential of QME in new application areas. To address this, we present a framework for analyzing sensitivity that incorporates the three main steps in QME image formation: mechanical deformation, its detection using optical coherence tomography (OCT), and signal processing used to estimate elasticity. Firstly, we present an analytical model of QME sensitivity, validated by experimental data, and demonstrate that sub-kPa elasticity sensitivity can be achieved in QME. Using silicone phantoms, we demonstrate that sensitivity is dependent on friction, OCT focus depth, and averaging methods in signal processing. For the first time, we show that whilst lubrication of layer improves accuracy by reducing surface friction, it reduces sensitivity due to the time-dependent effect of lubricant exudation from the layer boundaries resulting in increased friction. Furthermore, we demonstrate how signal processing in QME provides a trade-off between sensitivity and resolution that can be used to optimize imaging performance. We believe that our framework to analyze sensitivity can help to sustain the development of QME and, also, that it can be readily adapted to other OCE techniques.
Clinical feasibility of optical coherence micro-elastography for imaging tumor margins in breast-conserving surgery
Publisher: Optica Publishing Group
Date: 19-11-2018
DOI: 10.1364/BOE.9.006331
Data from Quantitative Micro-Elastography Enables In Vivo Detection of Residual Cancer in the Surgical Cavity during Breast-Conserving Surgery
Publisher: American Association for Cancer Research (AACR)
Date: 31-03-2023
DOI: 10.1158/0008-5472.C.6514023.V1
Abstract: Abstract Breast-conserving surgery (BCS) is commonly used for the treatment of early-stage breast cancer. Following BCS, approximately 20% to 30% of patients require reexcision because postoperative histopathology identifies cancer in the surgical margins of the excised specimen. Quantitative micro-elastography (QME) is an imaging technique that maps microscale tissue stiffness and has demonstrated a high diagnostic accuracy (96%) in detecting cancer in specimens excised during surgery. However, current QME methods, in common with most proposed intraoperative solutions, cannot image cancer directly in the patient, making their translation to clinical use challenging. In this proof-of-concept study, we aimed to determine whether a handheld QME probe, designed to interrogate the surgical cavity, can detect residual cancer directly in the breast cavity i in vivo /i during BCS. In a first-in-human study, 21 BCS patients were scanned i in vivo /i with the QME probe by five surgeons. For validation, protocols were developed to coregister i in vivo /i QME with postoperative histopathology of the resected tissue to assess the capability of QME to identify residual cancer. In four cavity aspects presenting cancer and 21 cavity aspects presenting benign tissue, QME detected elevated stiffness in all four cancer cases, in contrast to low stiffness observed in 19 of the 21 benign cases. The results indicate that i in vivo /i QME can identify residual cancer by directly imaging the surgical cavity, potentially providing a reliable intraoperative solution that can enable more complete cancer excision during BCS. Significance: Optical imaging of microscale tissue stiffness enables the detection of residual breast cancer directly in the surgical cavity during breast-conserving surgery, which could potentially contribute to more complete cancer excision. /
Volume Adaptation Controls Stem Cell Mechanotransduction
Publisher: American Chemical Society (ACS)
Date: 12-11-2019
Abstract: Recent studies have found discordant mechanosensitive outcomes when comparing 2D and 3D, highlighting the need for tools to study mechanotransduction in 3D across a wide spectrum of stiffness. A gelatin methacryloyl (GelMA) hydrogel with a continuous stiffness gradient ranging from 5 to 38 kPa was developed to recapitulate physiological stiffness conditions. Adipose-derived stem cells (ASCs) were encapsulated in this hydrogel, and their morphological characteristics and expression of both mechanosensitive proteins (Lamin A, YAP, and MRTFa) and differentiation markers (PPARγ and RUNX2) were analyzed. Low-stiffness regions (∼8 kPa) permitted increased cellular and nuclear volume and enhanced mechanosensitive protein localization in the nucleus. This trend was reversed in high stiffness regions (∼30 kPa), where decreased cellular and nuclear volumes and reduced mechanosensitive protein nuclear localization were observed. Interestingly, cells in soft regions exhibited enhanced osteogenic RUNX2 expression, while those in stiff regions upregulated the adipogenic regulator PPARγ, suggesting that volume, not substrate stiffness, is sufficient to drive 3D stem cell differentiation. Inhibition of myosin II (Blebbistatin) and ROCK (Y-27632), both key drivers of actomyosin contractility, resulted in reduced cell volume, especially in low-stiffness regions, causing a decorrelation between volume expansion and mechanosensitive protein localization. Constitutively active and inactive forms of the canonical downstream mechanotransduction effector TAZ were stably transfected into ASCs. Activated TAZ resulted in higher cellular volume despite increasing stiffness and a consistent, stiffness-independent translocation of YAP and MRTFa into the nucleus. Thus, volume adaptation as a function of 3D matrix stiffness can control stem cell mechanotransduction and differentiation.
Depth-encoded optical coherence elastography for simultaneous volumetric imaging of two tissue faces
Publisher: The Optical Society
Date: 17-03-2017
DOI: 10.1364/OL.42.001233
Investigation of optical attenuation imaging using optical coherence tomography for monitoring of scars undergoing fractional laser treatment
Publisher: Wiley
Date: 31-05-2017
Abstract: We demonstrate the use of the near-infrared attenuation coefficient, measured using optical coherence tomography (OCT), in longitudinal assessment of hypertrophic burn scars undergoing fractional laser treatment. The measurement method incorporates blood vessel detection by speckle decorrelation and masking, and a robust regression estimator to produce 2D en face parametric images of the attenuation coefficient of the dermis. Through reliable co-location of the field of view across pre- and post-treatment imaging sessions, the study was able to quantify changes in the attenuation coefficient of the dermis over a period of ∼20 weeks in seven patients. Minimal variation was observed in the mean attenuation coefficient of normal skin and control (untreated) mature scars, as expected. However, a significant decrease (13 ± 5%, mean ± standard deviation) was observed in the treated mature scars, resulting in a greater distinction from normal skin in response to localized damage from the laser treatment. By contrast, we observed an increase in the mean attenuation coefficient of treated (31 ± 27%) and control (27 ± 20%) immature scars, with numerical values incrementally approaching normal skin as the healing progressed. This pilot study supports conducting a more extensive investigation of OCT attenuation imaging for quantitative longitudinal monitoring of scars. En face 2D OCT attenuation coefficient map of a treated immature scar derived from the pre-treatment (top) and the post-treatment (bottom) scans. (Vasculature (black) is masked out.) The scale bars are 0.5 mm.
Combined Diffusion Tensor Imaging and Quantitative Susceptibility Mapping Discern Discrete Facets of White Matter Pathology Post-injury in the Rodent Brain
Publisher: Frontiers Media SA
Date: 06-03-2020
Analysis of spatial resolution in phase-sensitive compression optical coherence elastography
Publisher: The Optical Society
Date: 28-02-2019
Data from Quantitative Micro-Elastography Enables In Vivo Detection of Residual Cancer in the Surgical Cavity during Breast-Conserving Surgery
Publisher: American Association for Cancer Research (AACR)
Date: 31-03-2023
DOI: 10.1158/0008-5472.C.6514023
Abstract: Abstract Breast-conserving surgery (BCS) is commonly used for the treatment of early-stage breast cancer. Following BCS, approximately 20% to 30% of patients require reexcision because postoperative histopathology identifies cancer in the surgical margins of the excised specimen. Quantitative micro-elastography (QME) is an imaging technique that maps microscale tissue stiffness and has demonstrated a high diagnostic accuracy (96%) in detecting cancer in specimens excised during surgery. However, current QME methods, in common with most proposed intraoperative solutions, cannot image cancer directly in the patient, making their translation to clinical use challenging. In this proof-of-concept study, we aimed to determine whether a handheld QME probe, designed to interrogate the surgical cavity, can detect residual cancer directly in the breast cavity i in vivo /i during BCS. In a first-in-human study, 21 BCS patients were scanned i in vivo /i with the QME probe by five surgeons. For validation, protocols were developed to coregister i in vivo /i QME with postoperative histopathology of the resected tissue to assess the capability of QME to identify residual cancer. In four cavity aspects presenting cancer and 21 cavity aspects presenting benign tissue, QME detected elevated stiffness in all four cancer cases, in contrast to low stiffness observed in 19 of the 21 benign cases. The results indicate that i in vivo /i QME can identify residual cancer by directly imaging the surgical cavity, potentially providing a reliable intraoperative solution that can enable more complete cancer excision during BCS. Significance: Optical imaging of microscale tissue stiffness enables the detection of residual breast cancer directly in the surgical cavity during breast-conserving surgery, which could potentially contribute to more complete cancer excision. /
Immune‐mediated ECM depletion improves tumour perfusion and payload delivery
Publisher: EMBO
Date: 11-11-2019
In vivo optical coherence tomography attenuation imaging of the breast surgical cavity using a handheld probe
Publisher: Elsevier BV
Date: 11-2023
Quantitative Micro-Elastography Enables In Vivo Detection of Residual Cancer in the Surgical Cavity during Breast-Conserving Surgery
Publisher: American Association for Cancer Research (AACR)
Date: 13-09-2022
DOI: 10.1158/0008-5472.CAN-22-0578
Abstract: Optical imaging of microscale tissue stiffness enables the detection of residual breast cancer directly in the surgical cavity during breast-conserving surgery, which could potentially contribute to more complete cancer excision.
Strain Tensor Imaging in Compression Optical Coherence Elastography
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2019
Stereoscopic optical palpation for tumour margin assessment in breast-conserving surgery
Publisher: Elsevier BV
Date: 07-2023
A surgically optimized intraoperative poly(I:C)-releasing hydrogel prevents cancer recurrence
Publisher: Elsevier BV
Date: 07-2023
Characterizing the elasticity of skeletal muscle using quantitative micro-elastography
Publisher: SPIE
Date: 09-12-2021
DOI: 10.1117/12.2616056
Multimodal optical coherence microscopy, mechano-microscopy and fluorescence microscopy for three-dimensional characterization of multicellular spheroids
Publisher: SPIE
Date: 11-08-2023
DOI: 10.1117/12.2670830
Polarisation Dependent Dynamics in Bulk Semiconductor Optical Amplifiers
Publisher: IEEE
Date: 06-2006
Wide-field optical coherence micro-elastography for intraoperative assessment of human breast cancer margins
Publisher: The Optical Society
Date: 19-09-2016
DOI: 10.1364/BOE.7.004139
Three-dimensional optical coherence elastography by phase-sensitive comparison of C-scans
Publisher: SPIE-Intl Soc Optical Eng
Date: 07-07-2014
Objective quantification of burn scar stiffness using shear-wave elastography
Publisher: Elsevier BV
Date: 12-2020
Audio frequencyin vivooptical coherence elastography
Publisher: IOP Publishing
Date: 06-05-2009
DOI: 10.1088/0031-9155/54/10/011
Abstract: We present a new approach to optical coherence elastography (OCE), which probes the local elastic properties of tissue by using optical coherence tomography to measure the effect of an applied stimulus in the audio frequency range. We describe the approach, based on analysis of the Bessel frequency spectrum of the interferometric signal detected from scatterers undergoing periodic motion in response to an applied stimulus. We present quantitative results of sub-micron excitation at 820 Hz in a layered phantom and the first such measurements in human skin in vivo.
Multiple scattering detection in optical coherence tomography using speckle statistics
Publisher: IEEE
Date: 2010
Experimental analysis of phase conjugation properties of four-wave mixing in an SOA after probe broadening due to fibre dispersion
Publisher: Elsevier BV
Date: 04-2008
Polarization Resolved Four-Wave-Mixing-Based Measurement in Bulk Material Semiconductor Optical Amplifier
Publisher: IEEE
Date: 06-2006
Coherence function-encoded optical palpation
Publisher: Optica Publishing Group
Date: 08-09-2021
DOI: 10.1364/OL.430117
Abstract: Optical palpation maps stress at the surface of biological tissue into 2D images. It relies on measuring surface deformation of a compliant layer, which to date has been performed with optical coherence tomography (OCT). OCT-based optical palpation holds promise for improved clinical diagnostics however, the complexity and cost hinder broad adoption. In this Letter, we introduce coherence function-encoded optical palpation (CFE-OP) using a novel optical profilometry technique that exploits the envelope of the coherence function rather than its peak position, which is typically used to retrieve depth information. CFE-OP utilizes a Fabry–Perot laser diode (bandwidth, 2.2 nm) and a single photodiode in a Michelson interferometer to detect the position along the coherence envelope as a function of path length. This technique greatly reduces complexity and cost in comparison to the OCT-based approach. We perform CFE-OP on phantom and excised human breast tissue, demonstrating comparable mechanical contrast to OCT-based optical palpation and the capability to distinguish stiff tumor from soft benign tissue.
Pump–Probe Detuning Dependence of Four-Wave Mixing Pulse in an SOA
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2007
Deciphering Cell-to-Cell Communication in Acquisition of Cancer Traits: Extracellular Membrane Vesicles Are Regulators of Tissue Biomechanics
Publisher: Mary Ann Liebert Inc
Date: 08-2016
Abstract: Deciphering the role of cell-to-cell communication in acquisition of cancer traits such as metastasis is one of the key challenges of integrative biology and clinical oncology. In this context, extracellular vesicles (EVs) are important vectors in cell-to-cell communication and serve as conduits in the transfer of cellular constituents required for cell function and for the establishment of cellular phenotypes. In the case of malignancy, they have been shown to support the acquisition of common traits defined as constituting the hallmarks of cancer. Cellular biophysics has contributed to our understanding of some of these central traits with changes in tissue biomechanics reflective of cell state. Indeed, much is known about stiffness of the tissue scaffold in the context of cell invasion and migration. This article advances this knowledge frontier by showing for the first time that EVs are mediators of tissue biomechanical properties and, importantly, demonstrates a link between the acquisition of cancer multidrug resistance and increased tissue stiffness of the malignant mass. The methodology used in the study employed optical coherence elastography and atomic force microscopy on breast cancer cell monolayers and tumor spheroids. Specifically, we show here that the acquired changes in tissue stiffness can be attributed to the intracellular transfer of a protein complex comprising ezrin, radixin, moesin, CD44, and P-glycoprotein. This has important implications in facilitating mechano-transduced signaling cascades that regulate the acquisition of cancer traits, such as invasion and metastasis. Finally, this study also introduces novel targets and strategies for diagnostic and therapeutic innovation in oncology, with a view to prevention of metastatic spread and personalized medicine in cancer treatment.
Speckle reduction in optical coherence tomography by strain compounding
Publisher: Optica Publishing Group
Date: 13-07-2010
DOI: 10.1364/OL.35.002445
Ultrahigh-resolution optical coherence elastography through a micro-endoscope: towards in vivo imaging of cellular-scale mechanics
Publisher: The Optical Society
Date: 20-10-2017
DOI: 10.1364/BOE.8.005127
Special Section Guest Editorial: Optical Elastography and Measurement of Tissue Biomechanics
Publisher: SPIE-Intl Soc Optical Eng
Date: 19-12-2013
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