1. Articles from Ken Y. Foo

    1-9 of 9
    1. Multi-class classification of breast tissue using optical coherence tomography and attenuation imaging combined via deep learning

      Multi-class classification of breast tissue using optical coherence tomography and attenuation imaging combined via deep learning

      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 ...

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    2. Speckle-dependent accuracy in phase-sensitive optical coherence tomography

      Speckle-dependent accuracy in phase-sensitive optical coherence tomography

      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 samples, 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 ...

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    3. Optical palpation for tumor margin assessment in breast-conserving surgery

      Optical palpation for tumor margin assessment in breast-conserving surgery

      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 ...

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    4. Camera-based optical palpation

      Camera-based optical palpation

      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 ...

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    5. Feature Of The Week 04.26.2020: Diagnostic Accuracy of Quantitative Micro-Elastography for Margin Assessment in Breast-Conserving Surgery

      Feature Of The Week 04.26.2020: Diagnostic Accuracy of Quantitative Micro-Elastography for Margin Assessment in Breast-Conserving Surgery

      Inadequate margins in breast-conserving surgery (BCS) are associated with an increased likelihood of local recurrence of breast cancer. Currently, approximately 20% of BCS patients require repeat surgery due to inadequate margins at the initial operation. Implementation of an accurate, intraoperative margin assessment tool may reduce this re-excision rate. This study determined, for the first time, the diagnostic accuracy of quantitative micro-elastography (QME), an optical coherence tomography (OCT)–based elastography technique that produces images of tissue microscale elasticity, for detecting tumor within 1 mm of the margins of BCS specimens. Simultaneous OCT and QME were performed on the margins of intact ...

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    6. Diagnostic Accuracy of Quantitative Micro-Elastography for Margin Assessment in Breast-Conserving Surgery

      Diagnostic Accuracy of Quantitative Micro-Elastography for Margin Assessment in Breast-Conserving Surgery

      Inadequate margins in breast-conserving surgery (BCS) are associated with an increased likelihood of local recurrence of breast cancer. Currently, approximately 20% of BCS patients require repeat surgery due to inadequate margins at the initial operation. Implementation of an accurate, intraoperative margin assessment tool may reduce this re-excision rate. This study determined, for the first time, the diagnostic accuracy of quantitative micro-elastography (QME), an optical coherence tomography (OCT)–based elastography technique that produces images of tissue microscale elasticity, for detecting tumor within 1 mm of the margins of BCS specimens. Simultaneous OCT and QME were performed on the margins of intact ...

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    7. Three‐dimensional mapping of the attenuation coefficient in optical coherence tomography to enhance breast tissue micro‐architecture contrast

      Three‐dimensional mapping of the attenuation coefficient in optical coherence tomography to enhance breast tissue micro‐architecture contrast

      Effective intraoperative tumor margin assessment is needed to reduce re‐excision rates in breast‐conserving surgery (BCS). Mapping the attenuation coefficient in optical coherence tomography (OCT) throughout a sample to create an image (attenuation imaging) is one promising approach. For the first time, three‐dimensional OCT attenuation imaging of human breast tissue micro‐architecture using a wide‐field (up to ~45 × 45 × 3.5 mm) imaging system is demonstrated. Representative results from three mastectomy and one BCS specimen (from 31 specimens) are presented with co‐registered postoperative histology. Attenuation imaging is shown to provide substantially improved contrast over OCT, delineating ...

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    8. Handheld volumetric manual compression‐based quantitative micro‐elastography

      Handheld volumetric manual compression‐based quantitative micro‐elastography

      Compression optical coherence elastography typically requires a mechanical actuator to impart a controlled uniform strain to the sample. However, for handheld scanning, this adds complexity to the design of the probe and the actuator stroke limits the amount of strain that can be applied. In this work, we present a new volumetric imaging approach that utilises bidirectional manual compression via the natural motion of the user's hand to induce strain to the sample, realising compact, actuator‐free, handheld compression optical coherence elastography. In this way, we are able to demonstrate rapid acquisition of three‐dimensional quantitative micro‐elastography (QME ...

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    9. Clinical feasibility of optical coherence micro-elastography for imaging tumor margins in breast-conserving surgery

      Clinical feasibility of optical coherence micro-elastography for imaging tumor margins in breast-conserving surgery

      It has been demonstrated that optical coherence micro-elastography (OCME) provides additional contrast of tumor compared to optical coherence tomography (OCT) alone. Previous studies, however, have predominantly been performed on mastectomy specimens. Such specimens typically differ substantially in composition and geometry from the more clinically relevant wide-local excision (WLE) specimens excised during breast-conserving surgery. As a result, it remains unclear if the mechanical contrast observed is maintained in WLE specimens. In this manuscript, we begin to address this issue by performing a feasibility study of OCME on 17 freshly excised, intact WLE specimens. In addition, we present two developments required to ...

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    1-9 of 9
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  2. Topics in the News

    1. (8 articles) University of Western Australia
    2. (3 articles) OncoRes Medical
    3. (2 articles) Thorlabs
    4. (1 articles) University College London
    5. (1 articles) San Raffaele Scientfic Institute
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    Clinical feasibility of optical coherence micro-elastography for imaging tumor margins in breast-conserving surgery Handheld volumetric manual compression‐based quantitative micro‐elastography Three‐dimensional mapping of the attenuation coefficient in optical coherence tomography to enhance breast tissue micro‐architecture contrast Diagnostic Accuracy of Quantitative Micro-Elastography for Margin Assessment in Breast-Conserving Surgery Feature Of The Week 04.26.2020: Diagnostic Accuracy of Quantitative Micro-Elastography for Margin Assessment in Breast-Conserving Surgery Camera-based optical palpation Optical palpation for tumor margin assessment in breast-conserving surgery Speckle-dependent accuracy in phase-sensitive optical coherence tomography Multi-class classification of breast tissue using optical coherence tomography and attenuation imaging combined via deep learning Intraoperative Optical Coherence Tomography in Idiopathic Macular Epiretinal Membrane Surgery Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives Non-cystic macular thickening on optical coherence tomography as an alternative to fluorescein angiography for predicting retinal vascular leakage in early stages of uveitis