1. Articles from Kelsey M. Kennedy

    1-17 of 17
    1. 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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    2. 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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    3. 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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    4. Wide-field quantitative micro-elastography of human breast tissue

      Wide-field quantitative micro-elastography of human breast tissue

      Currently, 20-30% of patients undergoing breast-conserving surgery require a second surgery due to insufficient surgical margins in the initial procedure. We have developed a wide-field quantitative micro-elastography system for the assessment of tumor margins. In this technique, we map tissue elasticity over a field-of-view of ~46 × 46 mm. We performed wide-field quantitative micro-elastography on thirteen specimens of freshly excised tissue acquired from patients undergoing a mastectomy. We present wide-field optical coherence tomography (OCT) images, qualitative (strain) micro-elastograms and quantitative (elasticity) micro-elastograms, acquired in 10 minutes. We demonstrate that wide-field quantitative micro-elastography can extend the range of tumors visible using OCT-based ...

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    5. Investigation of optical coherence micro-elastography as a method to visualize micro-architecture in human axillary lymph nodes

      Investigation of optical coherence micro-elastography as a method to visualize micro-architecture in human axillary lymph nodes

      Background Evaluation of lymph node involvement is an important factor in detecting metastasis and deciding whether to perform axillary lymph node dissection (ALND) in breast cancer surgery. As ALND is associated with potentially severe long term morbidity, the accuracy of lymph node assessment is imperative in avoiding unnecessary ALND. The mechanical properties of malignant lymph nodes are often distinct from those of normal nodes. A method to image the micro-scale mechanical properties of lymph nodes could, thus, provide diagnostic information to aid in the assessment of lymph node involvement in metastatic cancer. In this study, we scan axillary lymph nodes ...

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    6. Investigation of optical coherence micro-elastography as a method to visualize cancers in human breast tissue

      Investigation of optical coherence micro-elastography as a method to visualize cancers in human breast tissue

      Accurate intraoperative identification of malignant tissue is a challenge in the surgical management of breast cancer. Imaging techniques that help address this challenge could contribute to more complete and accurate tumor excision, and thereby help reduce the current high re-excision rates without resorting to the removal of excess healthy tissue. Optical coherence micro-elastography (OCME) is a three-dimensional, high-resolution imaging technique that is sensitive to micro-scale variations of the mechanical properties of tissue. As tumor modifies the mechanical properties of breast tissue, OCME has the potential to identify, on the micro-scale, involved regions of fresh, unstained tissue. OCME is based on ...

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    7. Optical Coherence Elastography

      Optical Coherence Elastography

      S ince the days of Hippocrates, as early as 400 B.C.E., physicians have used palpation—probing by touch—to identify diseased tissue by variations in its mechanical properties. In the modern clinic, the uses of palpation range from assessment of skin lesions to the guidance of the surgical excision of tumors. Indeed, the usefulness of palpation has, over the past 25 years, given rise to a new family of imaging techniques—known as elastography—that map the spatial variation of the mechanical properties of diseased tissue, with greater accuracy and often much higher resolution than can be achieved ...

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    8. Three-dimensional optical coherence micro-elastography of skeletal muscle tissue

      Three-dimensional optical coherence micro-elastography of skeletal muscle tissue

      In many muscle pathologies, impairment of skeletal muscle function is closely linked to changes in the mechanical properties of the muscle constituents. Optical coherence micro-elastography (OCME) uses optical coherence tomography (OCT) imaging of tissue under a quasi-static, compressive mechanical load to map variations in tissue mechanical properties on the micro-scale. We present the first study of OCME on skeletal muscle tissue. We show that this technique can resolve features of muscle tissue including fibers, fascicles and tendon, and can also detect necrotic lesions in skeletal muscle from the mdx mouse model of Duchenne muscular dystrophy. In many instances, OCME provides ...

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    9. Optical coherence micro-elastography: mechanical-contrast imaging of tissue microstructure

      Optical coherence micro-elastography: mechanical-contrast imaging of tissue microstructure

      We present optical coherence micro-elastography, an improved form of compression optical coherence elastography. We demonstrate the capacity of this technique to produce en face images, closely corresponding with histology, that reveal micro-scale mechanical contrast in human breast and lymph node tissues. We use phase-sensitive, three-dimensional optical coherence tomography (OCT) to probe the nanometer-to-micrometer-scale axial displacements in tissues induced by compressive loading. Optical coherence micro-elastography incorporates common-path interferometry, weighted averaging of the complex OCT signal and weighted least-squares regression. Using three-dimensional phase unwrapping, we have increased the maximum detectable strain eleven-fold over no unwrapping and the minimum detectable strain is 2 ...

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    10. Optical palpation: optical coherence tomography-based tactile imaging using a compliant sensor

      Optical palpation: optical coherence tomography-based tactile imaging using a compliant sensor

      We present optical palpation, a tactile imaging technique for mapping micrometer- to millimeter-scale mechanical variations in soft tissue. In optical palpation, a stress sensor consisting of translucent, compliant silicone with known stress–strain behavior is placed on the tissue surface and a compressive load is applied. Optical coherence tomography (OCT) is used to measure the local strain in the sensor, from which the local stress at the sample surface is calculated and mapped onto an image. We present results in tissue-mimicking phantoms, demonstrating the detection of a feature embedded 4.7 mm below the sample surface, well beyond the depth ...

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    11. Needle optical coherence elastography for the measurement of microscale mechanical contrast deep within human breast tissues

      Needle optical coherence elastography for the measurement of microscale mechanical contrast deep within human breast tissues

      Optical coherence elastography (OCE) is an emerging imaging technique that probes microscale mechanical contrast in tissues with the potential to differentiate healthy and malignant tissues. However, conventional OCE techniques are limited to imaging the first 1 to 2 mm of tissue in depth. We demonstrate, for the first time, OCE measurements deep within human tissues using needle OCE, extending the potential of OCE as a surgical guidance tool. We use needle OCE to detect tissue interfaces based on mechanical contrast in both normal and malignant breast tissues in freshly excised human mastectomy samples, as validated against histopathology. Further, we demonstrate ...

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    12. A Review of Optical Coherence Elastography: Fundamentals, Techniques and Prospects

      A Review of Optical Coherence Elastography: Fundamentals, Techniques and Prospects

      In optical coherence elastography, images are formed by mapping a mechanical property of tissue. Such images, known as elastograms, are formed on the microscale, intermediate between that of cells and whole organs. Optical coherence elastography holds great promise for detecting and monitoring the altered mechanical properties that accompany many clinical conditions and pathologies, particularly in cancer, cardiovascular disease and eye disease. In this review, we first consider how the mechanical properties of tissue are linked with tissue function and pathology. We then describe currently prominent optical coherence elastography techniques, with emphasis on the methods of mechanical loading and displacement estimation ...

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    13. OCT News 2013 Student Paper Awarded to Kelsey Kennedy from The University of Western Australia

      OCT News 2013 Student Paper Awarded to Kelsey Kennedy from The University of Western Australia

      Kelsey Kennedy from The University of Western Australia was a winner of the 2013 OCT News Student Paper Award for her submission “Needle Optical Coherence Elastography for Elastic Contrast of Deep Tissues.” Below is a summary of her work: Cancerous breast tumors often manifest as stiff lesions within soft tissue. Surgeons use preoperative imaging and manual palpation of the tumor during surgery to guide excision. Intraoperative frozen section histology is possible but typically impractical and, thus, postoperative histological analysis is the gold-standard technique to assess whether sufficient tissue has been removed. Despite these measures, insufficient tissue is removed in approximately ...

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    14. A Microscope in a Needle

      A Microscope in a Needle

      A microscope small enough to fit into a needle creates many new possibilities for optics in medicine. We have developed a range of optical coherence tomography (OCT) needle probes. Connected to an OCT scanner via a single mode fiber, the probes are constructed by fusing exact lengths of no-core fiber and graded-index fiber to focus a broadband light beam. We terminated the optics with anglepolished, gold-coated no-core fiber to deflect the beam. Encased in a needle (outer diameter 310 ?m), these probes are capable of 3-D imaging. However, the important developments of 2012 have been where we have taken these ...

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    15. Improved measurement of vibration amplitude in dynamic optical coherence elastography

      Improved measurement of vibration amplitude in dynamic optical coherence elastography

      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 ...

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    16. Needle optical coherence elastography for tissue boundary detection

      Needle optical coherence elastography for tissue boundary detection

      We incorporate, for the first time, optical coherence elastography (OCE) into a needle probe and demonstrate its ability to measure the microscopic deformation of soft tissues located well beyond the depth limit of reports to date. Needle OCE utilizes the force imparted by the needle tip as the loading mechanism and measures tissue deformation ahead of the needle during insertion. Measurements were performed in tissue-mimicking phantoms and ex vivo porcine trachea. Results demonstrate differentiation of tissues based on mechanical properties and highlight the potential of needle OCE for in vivo tissue boundary detection.

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    17. Review of tissue simulating phantoms with controllable optical, mechanical and structural properties for use in optical coherence tomography

      Review of tissue simulating phantoms with controllable optical, mechanical and structural properties for use in optical coherence tomography

      We review the development of phantoms for optical coherence tomography (OCT) designed to replicate the optical, mechanical and structural properties of a range of tissues. Such phantoms are a key requirement for the continued development of OCT techniques and applications. We focus on phantoms based on silicone, fibrin and poly(vinyl alcohol) cryogels (PVA-C), as we believe these materials hold the most promise for durable and accurate replication of tissue properties.

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    1-17 of 17
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  2. Topics in the News

    1. (16 articles) University of Western Australia
    2. (16 articles) Brendan F. Kennedy
    3. (15 articles) Kelsey M. Kennedy
    4. (13 articles) David D. Sampson
    5. (8 articles) Robert A. McLaughlin
    6. (6 articles) Andrea Curatolo
    7. (2 articles) OncoRes Medical
    8. (2 articles) Medical University of Vienna
    9. (1 articles) Boon Y. Yeo
    10. (1 articles) Rodney W. Kirk
    11. (1 articles) Guy Lamouche
    12. (1 articles) Nara Medical University
    13. (1 articles) K. U. Leuven
    14. (1 articles) University of Alabama
    15. (1 articles) Singapore Eye Research Institute
    16. (1 articles) Michael Pircher
    17. (1 articles) Taishi Yonetsu
    18. (1 articles) Ursula Schmidt-Erfurth
    19. (1 articles) Tsunekazu Kakuta
    20. (1 articles) Dalip Singh Mehta
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    Review of tissue simulating phantoms with controllable optical, mechanical and structural properties for use in optical coherence tomography Needle optical coherence elastography for tissue boundary detection Improved measurement of vibration amplitude in dynamic optical coherence elastography A Microscope in a Needle OCT News 2013 Student Paper Awarded to Kelsey Kennedy from The University of Western Australia A Review of Optical Coherence Elastography: Fundamentals, Techniques and Prospects Needle optical coherence elastography for the measurement of microscale mechanical contrast deep within human breast tissues Optical palpation: optical coherence tomography-based tactile imaging using a compliant sensor Optical Coherence Elastography Investigation of optical coherence micro-elastography as a method to visualize cancers in human breast tissue High space-bandwidth in quantitative phase imaging using partially spatially coherent optical coherence microscopy and deep neural network Optical coherence tomography assessment of macrophages accumulation in non-ST-segment elevation acute coronary syndromes