1. Articles from Amit S. Paranjape

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    1. Optical coherence contrast imaging using gold nanorods in living mice eyes

      Optical coherence contrast imaging using gold nanorods in living mice eyes

      Background Optical Coherence Tomography (OCT) is a powerful imaging modality to visualize tissue structures, with axial image pixel resolution as high as 1.6 um in tissue. However, OCT is intrinsically limited to providing structural information as the OCT contrast is produced by optically scattering tissues. Methods Here we demonstrate gold nanorods (GNRs) injected into the anterior chamber (AC) and cornea of mice eyes can create a significant OCT signal and hence can be used as a contrast agent for in vivo OCT imaging. Results We show that a low dose of 30 nM of GNRs (13 nm in diameter ...

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    2. Optimized retinal nerve fiber layer segmentation based on optical reflectivity and birefringence for polarization-sensitive optical coherence tomography

      Optimized retinal nerve fiber layer segmentation based on optical reflectivity and birefringence for polarization-sensitive optical coherence tomography

      Segmentation of the retinal nerve fiber layer (RNFL) from swept source polarization-sensitive optical coherence tomography (SS-PSOCT) images is required to determine RNFL thickness and calculate birefringence. Traditional RNFL segmentation methods based on image processing and boundary detection algorithms utilize only optical reflectivity contrast information, which is strongly affected by speckle noise. We present a novel approach to segment the retinal nerve fiber layer (RNFL) using SS-PSOCT images including both optical reflectivity and phase retardation information. The RNFL anterior boundary is detected based on optical reflectivity change due to refractive index difference between the vitreous and inner limiting membrane. The posterior ...

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    3. Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms

      Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms

      Melanoma accounts for 75% of all skin cancer deaths. Pulsed photothermal radiometry (PPTR), optical coherence tomography (OCT) and ultrasound (US) are non-invasive imaging techniques that may be used to measure melanoma thickness, thus, determining surgical margins. We constructed a series of PDMS tissue phantoms simulating melanomas of different thicknesses. PPTR, OCT and US measurements were recorded from PDMS tissue phantoms and results were compared in terms of axial imaging range, axial resolution and imaging time. A Monte Carlo simulation and three-dimensional heat transfer model was constructed to simulate PPTR measurement. Experimental results show that PPTR and US can provide a ...

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    4. Depth resolved photothermal OCT detection of macrophages in tissue using nanorose

      Depth resolved photothermal OCT detection of macrophages in tissue using nanorose

      Application of photothermal Optical Coherence Tomography (OCT) to detect macrophages in ex vivo rabbit arteries which have engulfed nanoclusters of gold coated iron oxide (nanorose) is reported. Nanorose engulfed by macrophages associated with atherosclerotic lesions in rabbit arteries absorb incident laser (800nm) energy and cause optical pathlength (OP) variation which is measured using photothermal OCT. OP variation in polydimethyl siloxane tissue phantoms containing varying concentrations of nanorose match values predicted from nanoparticle and material properties. Measurement of OP variation in rabbit arteries in response to laser excitation provides an estimate of nanorose concentration in atherosclerotic lesions of 2.5x109 particles ...

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    5. Near infrared femtosecond laser ablation of urinary calculi in water

      Pulsed light emitted from a near infrared (=800nm) femtosecond laser is capable of plasma induced photodisruption of various materials. We used femtosecond laser pulses to ablate human urinary calculi. Femtosecond pulsed laser interaction with urinary calculi was investigated with various stone compositions, different incident fluences and number of applied pulses. Spectral-domain optical coherence tomography was used to image cross sections of ablation craters on the surface of urinary calculi. Our results indicate that femtosecond laser pulses can ablate various calculi compositions. Crater diameter and depth varies from tens of microns to several hundred microns when up to 1000 pulses were ...

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    6. Quality assessment for spectral domain optical coherence tomography (OCT) images

      Retinal nerve fiber layer (RNFL) thickness, a measure of glaucoma progression, can be measured in images acquired by spectral domain optical coherence tomography (OCT). The accuracy of RNFL thickness estimation, however, is affected by the quality of the OCT images. In this paper, a new parameter, signal deviation (SD), which is based on the standard deviation of the intensities in OCT images, is introduced for objective assessment of OCT image quality. Two other objective assessment parameters, signal to noise ratio (SNR) and signal strength (SS), are also calculated for each OCT image. The results of the objective assessment are compared ...
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    7. Automated method for RNFL segmentation in spectral domain OCT

      Amit S. Paranjape, Badr Elmaanaoui, Jordan Dewelle et al. We introduce a method based on optical reflectivity changes to segment the retinal nerve fiber layer (RNFL) in images recorded using swept source spectral domain optical coherence tomography (OCT). The segmented image is used to determine the RNFL thickness. Simple filtering followed by edge detecti ... [Proc. SPIE Int. Soc. Opt. Eng. 6848, 68480N (2008)] published Tue Feb 12, 2008.
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    1-8 of 8
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    Depth resolved photothermal OCT detection of macrophages in tissue using nanorose Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms Optimized retinal nerve fiber layer segmentation based on optical reflectivity and birefringence for polarization-sensitive optical coherence tomography Optical coherence contrast imaging using gold nanorods in living mice eyes Non Exudative AMD Imaged With SS-OCT- Extension 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 Early disability in ambulatory patients with multiple sclerosis: optical coherence tomography versus visual evoked potentials, a comparative study Dueling Deep Q-Network for Unsupervised Inter-frame Eye Movement Correction in Optical Coherence Tomography Volumes Atlas of Optical Coherence Tomography for Glaucoma (Textbook) In-vivo analysis of iron-gold composite nanoparticles as potential exogenous contrast agents for Magnetomotive Optical Coherence Tomography (MMOCT) Automatic Classification of Volumetric Optical Coherence Tomography Images via Recurrent Neural Network