1. Articles from Jessica C. Ramella-Roman

    1-9 of 9
    1. Optical phantoms for biomedical polarimetry: a review

      Optical phantoms for biomedical polarimetry: a review

      Calibration, quantification, and standardization of the polarimetric instrumentation, as well as interpretation and understanding of the obtained data, require the development and use of well-calibrated phantoms and standards. We reviewed the status of tissue phantoms for a variety of applications in polarimetry; more than 500 papers are considered. We divided the phantoms into five groups according to their origin (biological/nonbiological) and fundamental polarimetric properties of retardation, depolarization, and diattenuation. We found that, while biological media are generally depolarizing, retarding, and diattenuating, only one of all the phantoms reviewed incorporated all these properties, and few considered at least combined retardation ...

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    2. Use of Mueller matrix colposcopy in the characterization of cervical collagen anisotrop

      Use of Mueller matrix colposcopy in the characterization of cervical collagen anisotrop

      Preterm birth (PTB) presents a serious medical heath concern in both economically developed and developing nations, with incidence rate from 15%-11% respectively. Changes in cervical collagen bundle orientation and distribution may prove to be a predictor of PTB. Polarization imaging is an effective means to measure optical anisotropy in birefringent biological tissue such as those rich in collagen. Non-invasive, full-field Mueller Matrix polarimetry (MMP) imaging methodologies, optical coherence tomography (OCT), and second harmonic generation (SHG) microscopy were used to assess cervical collagen content and structure in non-pregnant cervices. In vivo studies using a Mueller Matrix colposcope are underway. Further ...

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    3. Use of Mueller matrix polarimetry and optical coherence tomography in the characterization of cervical collagen anisotropy

      Use of Mueller matrix polarimetry and optical coherence tomography in the characterization of cervical collagen anisotropy

      Preterm birth (PTB) presents a serious medical heath concern throughout the world. There is a high incidence of PTB in both developed and developing countries ranging from 11%-15%, respectively. Studies have shown there may be numerous precursors to PTB including infections, genetic predisposition, nutrition and various other morbidities which all lead to a premature disorganization in the cervical collagen resulting in the weakening of the structure designed to keep the fetus in utero. The changes in cervical collagen orientation and distribution may prove to be a predictor of PTB. Polarization imaging is an effective means to measure optical anisotropy ...

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    4. Use of combined polarization-sensitive optical coherence tomography and Mueller matrix imaging for the polarimetric characterization of excised biological tissue

      Use of combined polarization-sensitive optical coherence tomography and Mueller matrix imaging for the polarimetric characterization of excised biological tissue

      Mueller matrix polarimetry and polarization-sensitive optical coherence tomography (PS-OCT) are two emerging techniques utilized in the assessment of tissue anisotropy. While PS-OCT can provide cross-sectional images of local tissue birefringence through its polarimetric sensitivity, Mueller matrix polarimetry can be used to measure bulk polarimetric properties such as depolarization, diattenuation, and retardance. To this day true quantification of PS-OCT data can be elusive, partly due to the reliance on inverse models for the characterization of tissue birefringence and the influence of instrumentation noise. Similarly for Mueller matrix polarimetry, calculation of retardance or depolarization may be influenced by tissue heterogeneities that could ...

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    5. Three-dimensional printing of tissue phantoms for biophotonic imaging

      Three-dimensional printing of tissue phantoms for biophotonic imaging

      We have investigated the potential of tissue phantoms fabricated with thermosoftening- and photopolymerization-based three-dimensional (3D) printers for use in evaluation of biophotonic imaging systems. The optical properties of printed polymer samples were measured and compared to biological tissues. Phantoms with subsurface channels as small as 0.2 mm in diameter were fabricated and imaged with microscopy, x-ray microtomography, and optical coherence tomography to characterize morphology. These phantoms were then implemented to evaluate the penetration depth of a hyperspectral reflectance imaging system used in conjunction with a near-infrared contrast agent. Results indicated that 3D printing may provide a suitable platform for ...

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    6. Quantitative transverse flow measurement using optical coherence tomography speckle decorrelation analysis

      Quantitative transverse flow measurement using optical coherence tomography speckle decorrelation analysis

      We propose an inter-Ascan speckle decorrelation based method that can quantitatively assess blood flow normal to the direction of the optical coherence tomography imaging beam. To validate this method, we performed a systematic study using both phantom and in vivo animal models. Results show that our speckle analysis method can accurately extract transverse flow speed with high spatial and temporal resolution.

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    7. Robust spectral-domain optical coherence tomography speckle model and its cross-correlation coefficient analysis

      Robust spectral-domain optical coherence tomography speckle model and its cross-correlation coefficient analysis

      In this study, we propose a generic speckle simulation for optical coherence tomography (OCT) signal, by convolving the point-spread function (PSF) of the OCT system with the numerically synthesized random sample field. We validate our model and use the simulation method to study the statistical properties of cross-correlation coefficients between A-scans, which have been recently applied in transverse motion analysis by our group. The results of simulation show that oversampling is essential for accurate motion tracking; exponential decay of OCT signal leads to an underestimate of motion that can be corrected; lateral heterogeneity of sample leads to an overestimate of ...

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    8. Microfluidics based phantoms of superficial vascular network

      Microfluidics based phantoms of superficial vascular network

      Several new bio-photonic techniques aim to measure flow in the human vasculature non-destructively. Some of these tools, such as laser speckle imaging or Doppler optical coherence tomography, are now reaching the clinical stage. Therefore appropriate calibration and validation techniques dedicated to these particular measurements are therefore of paramount importance. In this paper we introduce a fast prototyping technique based on laser micromachining for the fabrication of dynamic flow phantoms. Micro-channels smaller than 20 µm in width can be formed in a variety of materials such as epoxies, plastics, and household tape. Vasculature geometries can be easily and quickly modified to ...

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    9. Fabrication of microfluidic vascular phantoms by laser micromachining

      Fabrication of microfluidic vascular phantoms by laser micromachining

      Imaging of capillary structures and monitoring of blood flow within vasculature is becoming more common in clinical settings. However, very few dynamic phantoms exist which mimic capillary structures. We report the fabrication and testing of microfluidic, vascular phantoms aimed at the study of blood flow. These phantoms are fabricated using low-cost, off-the-shelf materials and require no lithographic processing, stamping, or embossing. Using laser micromachining, complex microfluidic structures can be fabricated in under an hour. The laser system is capable of producing microfluidic features with sizes on the order of tens of microns, over an area of several square centimeters. Because ...

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    1-9 of 9
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  2. Topics in the News

    1. (4 articles) Florida International University
    2. (2 articles) Johns Hopkins University
    3. (2 articles) Xuan Liu
    4. (2 articles) Yong Huang
    5. (2 articles) Jin U. Kang
    6. (2 articles) Amir Gandjbakhche
    7. (1 articles) University of Maryland
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    Microfluidics based phantoms of superficial vascular network Fabrication of microfluidic vascular phantoms by laser micromachining Robust spectral-domain optical coherence tomography speckle model and its cross-correlation coefficient analysis Quantitative transverse flow measurement using optical coherence tomography speckle decorrelation analysis Three-dimensional printing of tissue phantoms for biophotonic imaging Use of combined polarization-sensitive optical coherence tomography and Mueller matrix imaging for the polarimetric characterization of excised biological tissue Use of Mueller matrix polarimetry and optical coherence tomography in the characterization of cervical collagen anisotropy Use of Mueller matrix colposcopy in the characterization of cervical collagen anisotrop Optical phantoms for biomedical polarimetry: a review Duke University Engineering Professor Sina Farsiu Elected Fellow of the IEEE PhotoniCare Takes First Place at the 2019 HealthTECH Startup Competition Close Assessment and Testing for Chronic Graft Versus Host Disease, CATCH Study