1. Articles from Sreyankar Nandy

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    1. Assessment and Diagnosis of Human Ovarian and Colorectal Cancer using Optical and Photoacoustic Imaging (Thesis)

      Assessment and Diagnosis of Human Ovarian and Colorectal Cancer using Optical and Photoacoustic Imaging (Thesis)

      Optical imaging modalities have the advantage of high resolution, label free, rapid, low cost imaging for both in vivo and ex vivo diagnosis of biological tissues. Optical scattering, which is the main contrast of optical coherence tomography (OCT), is related to elastic scattering components, mainly stromal collagen. Tissue elasticity has recently emerged as an important diagnostic parameter associated with tumor development and progression and is also related to the distribution of structural components such as tissue collagen. We have used an optical coherence tomography elastography (OCTE) system for characterizing the differences in the micro-mechanical properties of benign and malignant human ...

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    2. 3D visualization of the ovarian tissue scattering coefficient with swept-source optical coherence tomography

      3D visualization of the ovarian tissue scattering coefficient with swept-source optical coherence tomography

      It is important to provide timely information to surgeons on diagnosis of a suspicious ovarian tissue before excision to avoid unnecessary surgery, especially for young women. In this report, we introduce a new 3-D surface mapping technique to map ovarian tissue scattering properties by fitting the swept-source optical coherence tomography (SS-OCT) signals to a scattering model. We observed that lower scattering coefficients and heterogeneous spatial distribution were associated with malignant ovarian tissues, and higher scattering coefficients and homogeneous spatial distribution indicated benign ovarian tissues. The initial results suggest that the 3-D scattering map has potential to be an effective tool ...

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      Mentions: Quing Zhu
    3. Classification of human ovarian tissue using full field optical coherence tomography

      Classification of human ovarian tissue using full field optical coherence tomography

      The feasibility of a full-field optical coherence tomography (FFOCT) system for rapid wide field optical analysis of normal and malignant human ovarian tissue pathologies was demonstrated. Five features were extracted from the normalized image histogram from 56 FFOCT images, based on the differences in the morphology of the normal and malignant tissue samples.

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    4. Classification and analysis of human ovarian tissue using full field optical coherence tomography

      Classification and analysis of human ovarian tissue using full field optical coherence tomography

      In this study, a full field optical coherence tomography (FFOCT) system was used to analyze and classify normal and malignant human ovarian tissue. 14 ovarian tissue samples (7 normal, 7 malignant) were imaged with the FFOCT system and five features were extracted by analyzing the normalized image histogram from 56 FFOCT images, based on the differences in the morphology of the normal and malignant tissue samples. A generalized linear model (GLM) classifier was trained using 36 images, and sensitivity of 95.3% and specificity of 91.1% was obtained. 20 images were used to test the model, and a sensitivity ...

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    5. Correlating optical coherence elastography based strain measurements with collagen content of the human ovarian tissue

      Correlating optical coherence elastography based strain measurements with collagen content of the human ovarian tissue

      In this manuscript, the initial feasibility of a catheter based phase stabilized swept source optical coherence tomography (OCT) system was studied for characterization of the strain inside different human ovarian tissue groups. The ovarian tissue samples were periodically compressed with 500 Hz square wave signal along the axial direction between the surface of an unfocused transducer and a glass cover slide. The displacement and corresponding strain were calculated during loading from different locations for each tissue sample. A total of 27 ex vivo ovaries from 16 patients were investigated. Statistically significant difference (p < 0.001) was observed between the average ...

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    6. Estimation of elastic parameters of ovarian tissue using phase stabilized swept source optical-coherence tomography

      Estimation of elastic parameters of ovarian tissue using phase stabilized swept source optical-coherence tomography

      We have estimated the micro-mechanical properties of ovarian tissue using phase-sensitive swept source optical coherence tomography. Ovary samples were mechanically excited by periodical vibration of an ultrasound transducer. The displacement and strain of the tissues were calculated during loading. Significant difference in strain was observed between the normal and malignant ovary groups, which indicates much softer and heterogeneous tissue structure for malignant ovaries. The initial results show that the phase sensitive swept source optical coherence elastography (OCE) can be an effective tool for characterization of stiffness and other micro-mechanical properties of normal and malignant ovarian tissue.

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    7. High-resolution full-field spatial coherence gated optical tomography using monochromatic light source

      High-resolution full-field spatial coherence gated optical tomography using monochromatic light source

      We demonstrate dispersion free, high-resolution full-field spatial coherence gated optical tomography using spatially incoherent monochromatic light source. Spatial coherence properties of light source were synthesized by means of combining a static diffuser and vibrating multi mode fiber bundle. Due to low spatial coherence of light source, the axial resolution of the system was achieved similar to that of conventional optical coherence tomography which utilizes low temporal coherence. Experimental results of fringe visibility versus optical path difference are presented for varying numerical apertures objective lenses. High resolution optically sectioned images of multilayer onion skin, and red blood cells are presented.

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    8. High-resolution corneal topography and tomography of fish eye using wide-field white light interference microscopy

      High-resolution corneal topography and tomography of fish eye using wide-field white light interference microscopy

      Topography and tomography of fish cornea is reconstructed using high resolution white light interference microscopy. White light interferograms at different depths were recorded by moving the object axially. For each depth position, five phase shifted interferograms were recorded and analyzed. From the reconstructed phase maps, the corneal topography and hence the refractive index was determined and from amplitude images the cross-sectional image of fish cornea was reconstructed. In the present method, we utilize a nearly common-path interference microscope and wide field illumination and hence do not require any mechanical B-scan. Therefore, the phase stability of the recorded data is improved.

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    1-8 of 8
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  2. Topics in the News

    1. (5 articles) Quing Zhu
    2. (4 articles) Melinda Sanders
    3. (3 articles) University of Connecticut
    4. (3 articles) Washington University in St. Louis
    5. (2 articles) Indian Institute of Technology at Delhi
    6. (2 articles) Molly Brewer
    7. (2 articles) Tianheng Wang
    8. (2 articles) Dalip Singh Mehta
    9. (1 articles) UCLA
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    11. (1 articles) Centre Hospitalier Intercommunal de Créteil
    12. (1 articles) Harvard University
    13. (1 articles) University of Maryland
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    17. (1 articles) University of Southern California
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    High-resolution corneal topography and tomography of fish eye using wide-field white light interference microscopy High-resolution full-field spatial coherence gated optical tomography using monochromatic light source Estimation of elastic parameters of ovarian tissue using phase stabilized swept source optical-coherence tomography Correlating optical coherence elastography based strain measurements with collagen content of the human ovarian tissue Classification and analysis of human ovarian tissue using full field optical coherence tomography Classification of human ovarian tissue using full field optical coherence tomography 3D visualization of the ovarian tissue scattering coefficient with swept-source optical coherence tomography Assessment and Diagnosis of Human Ovarian and Colorectal Cancer using Optical and Photoacoustic Imaging (Thesis) Optical coherence tomography-guided percutaneous coronary intervention: a review of current clinical applications Initial Study for the Determination of the Sequence of Intersecting Lines between Gel Pens and Seals by Optical Coherence Tomography Intraoperative optical coherence tomography-assisted displacement of prepapillary membrane in eyes with optic disc pit maculopathy Morphological Characteristics of Eroded Plaques with Noncritical Coronary Stenosis: An Optical Coherence Tomography Study