Publications (24)62.18 Total impact
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Article: Improved Detection Sensitivity of Line-Scanning Optical Coherence Microscopy.
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ABSTRACT: Optical coherence microscopy (OCM) is a promising technology for high-resolution cellular-level imaging in human tissues. Line-scanning OCM is a new form of OCM that utilizes line-field illumination for parallel detection. In this study, we demonstrate improved detection sensitivity by using an achromatic design for line-field generation. This system operates at 830-nm wavelength with 82-nm bandwidth. The measured axial resolution is 3.9 μm in air (corresponding to ~2.9 μm in tissue), and the transverse resolutions are 2.1 μm along the line-field illumination direction and 1.7 μm perpendicular to line illumination direction. The measured sensitivity is 98 dB with 25 line averages, resulting in an imaging speed of ~2 frames/s (516 lines/s). Real-time, cellular-level imaging of scattering tissues is demonstrated using human-colon specimens.IEEE Journal of Selected Topics in Quantum Electronics 05/2012; 18(3):1094-1099. · 3.78 Impact Factor -
Article: Computing prime factors with a Josephson phase qubit quantum processor
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ABSTRACT: A quantum processor (QuP) can be used to exploit quantum mechanics to find the prime factors of composite numbers[1]. Compiled versions of Shor's algorithm have been demonstrated on ensemble quantum systems[2] and photonic systems[3-5], however this has yet to be shown using solid state quantum bits (qubits). Two advantages of superconducting qubit architectures are the use of conventional microfabrication techniques, which allow straightforward scaling to large numbers of qubits, and a toolkit of circuit elements that can be used to engineer a variety of qubit types and interactions[6, 7]. Using a number of recent qubit control and hardware advances [7-13], here we demonstrate a nine-quantum-element solid-state QuP and show three experiments to highlight its capabilities. We begin by characterizing the device with spectroscopy. Next, we produces coherent interactions between five qubits and verify bi- and tripartite entanglement via quantum state tomography (QST) [8, 12, 14, 15]. In the final experiment, we run a three-qubit compiled version of Shor's algorithm to factor the number 15, and successfully find the prime factors 48% of the time. Improvements in the superconducting qubit coherence times and more complex circuits should provide the resources necessary to factor larger composite numbers and run more intricate quantum algorithms.02/2012; -
Article: Review of advanced imaging techniques.
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ABSTRACT: Pathology informatics encompasses digital imaging and related applications. Several specialized microscopy techniques have emerged which permit the acquisition of digital images ("optical biopsies") at high resolution. Coupled with fiber-optic and micro-optic components, some of these imaging techniques (e.g., optical coherence tomography) are now integrated with a wide range of imaging devices such as endoscopes, laparoscopes, catheters, and needles that enable imaging inside the body. These advanced imaging modalities have exciting diagnostic potential and introduce new opportunities in pathology. Therefore, it is important that pathology informaticists understand these advanced imaging techniques and the impact they have on pathology. This paper reviews several recently developed microscopic techniques, including diffraction-limited methods (e.g., confocal microscopy, 2-photon microscopy, 4Pi microscopy, and spatially modulated illumination microscopy) and subdiffraction techniques (e.g., photoactivated localization microscopy, stochastic optical reconstruction microscopy, and stimulated emission depletion microscopy). This article serves as a primer for pathology informaticists, highlighting the fundamentals and applications of advanced optical imaging techniques.Journal of pathology informatics. 01/2012; 3:22. -
Article: In vivo, label-free, three-dimensional quantitative imaging of kidney microcirculation using Doppler optical coherence tomography.
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ABSTRACT: Doppler optical coherence tomography (DOCT) is a functional extension of optical coherence tomography (OCT) and is currently being employed in several clinical arenas to quantify blood flow in vivo. In this study, the objective was to investigate the feasibility of DOCT to image kidney microcirculation, specifically, glomerular blood flow. DOCT is able to capture three-dimensional (3D) data sets consisting of a series of cross-sectional images in real time, which enables label-free and non-destructive quantification of glomerular blood flow. The kidneys of adult, male Munich-Wistar rats were exposed through laparotomy procedure after being anesthetized. Following exposure of the kidney beneath the DOCT microscope, glomerular blood flow was observed. The effects of acute mannitol and angiotensin II infusion were also observed. Glomerular blood flow was quantified for the induced physiological states and compared with baseline measurements. Glomerular volume, cumulative Doppler volume, and Doppler flow range parameters were computed from 3D OCT/DOCT data sets. Glomerular size was determined from OCT, and DOCT readily revealed glomerular blood flow. After infusion of mannitol, a significant increase in blood flow was observed and quantified, and following infusion of angiontensin II, a significant decrease in blood flow was observed and quantified. Also, blood flow histograms were produced to illustrate differences in blood flow rate and blood volume among the induced physiological states. We demonstrated 3D DOCT imaging of rat kidney microcirculation in the glomerulus in vivo. Dynamic changes in blood flow were detected under altered physiological conditions demonstrating the real-time imaging capability of DOCT. This method holds promise to allow non-invasive imaging of kidney blood flow for transplant graft evaluation or monitoring of altered-renal hemodynamics related to disease progression.Laboratory Investigation 08/2011; 91(11):1596-604. · 3.64 Impact Factor -
Article: Rh-I-UEA-1 polymerized liposomes target and image adenomatous polyps in the APC(Min/+) mouse using optical colonography.
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ABSTRACT: Mutated adenomatous polyposis coli (APC) genes predispose transformations to neoplasia, progressing to colorectal carcinoma. Early detection facilitates clinical management and therapy. Novel lectin-mediated polymerized targeted liposomes (Rh-I-UEA-1), with polyp specificity and incorporated imaging agents were fabricated to locate and image adenomatous polyps in APC(Min/+) mice. The biomarker α-L-fucose covalently joins the liposomal conjugated lectin Ulexeuropaeus agglutinin (UEA-1), via glycosidic linkage to the polyp mucin layer. Multispectral optical imaging (MSI) corroborated a global perspective of specific binding (rhodamine B 532 nm emission, 590-620 nm excitation) of targeted Rh-I-UEA-1 polymerized liposomes to polyps with 1.4-fold labeling efficiency. High-resolution coregistered optical coherence tomography (OCT) and fluorescence molecular imaging (FMI) reveal the spatial correlation of contrast distribution and tissue morphology. Freshly excised APC(Min) bowels were incubated with targeted liposomes (UEA-1 lectin), control liposomes (no lectin), or iohexol (Omnipaque) and imaged by the three techniques. Computed tomographic quantitative analyses did not confirm that targeted liposomes more strongly bound polyps than nontargeted liposomes or iohexol (Omnipaque) alone. OCT, with anatomic depth capabilities, along with the coregistered FMI, substantiated Rh-I-UEA-1 liposome binding along the mucinous polyp surface. UEA-1 lectin denotes α-l-fucose biomarker carbohydrate expression at the mucin glycoprotein layer; Rh-I-UEA-1 polymerized liposomes target and image adenomatous polyps in APC(Min) mice.Molecular Imaging 08/2011; 10(4):305-16. · 3.18 Impact Factor -
Article: Macroporous Hydrogel Scaffolds and Their Characterization By Optical Coherence Tomography.
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ABSTRACT: A simple porogen-leaching method to fabricate macroporous cyclic acetal hydrogel cell scaffolds is presented. Optical coherence tomography (OCT) was applied for nondestructive imaging and quantitative characterization of the scaffold structures. High-resolution OCT reveals the microstructures of the engineered tissue scaffolds in three dimensions. It also enables subsequent image processing to investigate quantitatively several key morphological design parameters for macroporous scaffolds, including the volume porosity, pore interconnectivity, and pore size. Two image-processing algorithms were adapted: three-dimensional labeling was applied to assess the interconnectivity, and erosion was applied to assess the pore size. Scaffolds with different design parameters were imaged, characterized, and compared. OCT imaging and image processing successfully discriminated scaffolds made from different formulations in terms of volume porosity, interconnectivity, and pore size. The cell viability and their spread across the scaffolds were confirmed by the fluorescence microscopy co-registered with OCT.Tissue Engineering Part C Methods 09/2010; · 4.64 Impact Factor -
Chapter: Combining Optical Coherence Tomography with Fluorescence Imaging
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ABSTRACT: In this chapter, we introduce several multimodal optical imaging techniques which combines OCT and fluorescence imaging. OCT provides high-resolution, cross-sectional imaging of tissue microstructure, while fluorescence imaging reveals the biochemical and/or molecular information. Multimodal optical imaging techniques which combine OCT and fluorescence imaging could provide morphological, molecular and functional information simultaneously, and have great potential in disease diagnostics and therapy. Several such multimodal systems as well as their biomedical applications are introduced and discussed in this chapter. An ongoing development of novel multimodal system (OCT/FLOT) is also briefly introduced.04/2010; , ISBN: 978-953-307-088-9 -
Article: Optical coherence tomography of human kidney.
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ABSTRACT: To determine histopathological status of living human kidneys in real time and a noninvasive fashion would be a significant advancement in renal disease diagnosis. Recently we reported that optical coherence tomography has the requisite high spatial resolution to noninvasively determine histopathological changes in rodent kidneys with microm scale resolution. We established whether optical coherence tomography could 1) effectively penetrate the connective tissue capsule surrounding human kidneys, 2) provide a global survey of the human renal surface and 3) determine histopathological changes in human renal microstructure. Using a high speed optical coherence tomography system equipped with a frequency swept laser light source (1.3 microm wavelength) we obtained cross-sectional images of 4 ex vivo human kidneys. All scanned sections underwent subsequent conventional light microscopic histological analysis, allowing direct comparisons. Optical coherence tomography enabled characterization of the tubules, glomeruli and cortical vessels with a penetration depth of up to 2 mm and 10 microm spatial resolution. We surveyed and imaged an entire human kidney within minutes in a noninvasive fashion. Acquired optical coherence tomography images documented histopathological changes in the tubules, glomeruli and interstitium that closely matched the conventional histological observations. Optical coherence tomography resolution and low cost, and the versatility of the probes required for imaging acquisition make this optical technology a promising modality to diagnose renal pathology.The Journal of urology 03/2010; 183(5):2090-4. · 4.02 Impact Factor -
Article: Co-registered optical coherence tomography and fluorescence molecular imaging for simultaneous morphological and molecular imaging.
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ABSTRACT: Optical coherence tomography (OCT) provides high-resolution, cross-sectional imaging of tissue microstructure in situ and in real time, while fluorescence molecular imaging (FMI) enables the visualization of basic molecular processes. There is a great deal of interest in combining these two modalities so that the tissue's structural and molecular information can be obtained simultaneously. This could greatly benefit biomedical applications such as detecting early diseases and monitoring therapeutic interventions. In this research, an optical system that combines OCT and FMI was developed. The system demonstrated that it could co-register en face OCT and FMI images with a 2.4 x 2.4 mm(2) field-of-view. The transverse resolutions of OCT and FMI of the system are both approximately 10 microm. Capillary tubes filled with fluorescent dye Cy 5.5 in different concentrations under a scattering medium are used as the phantom. En face OCT images of the phantoms were obtained and successfully co-registered with FMI images that were acquired simultaneously. A linear relationship between FMI intensity and dye concentration was observed. The relationship between FMI intensity and target fluorescence tube depth measured by OCT images was also observed and compared with theoretical modeling. This relationship could help in correcting reconstructed dye concentration. Imaging of colon polyps of the APC(min) mouse model is presented as an example of biological applications of this co-registered OCT/FMI system.Physics in Medicine and Biology 01/2010; 55(1):191-206. · 2.83 Impact Factor -
Article: Automated quantification of microstructural dimensions of the human kidney using optical coherence tomography (OCT).
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ABSTRACT: Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can non-invasively provide cross-sectional, high-resolution images of tissue morphology in situ and in real-time. We previously demonstrated that OCT is capable of visualizing characteristic kidney anatomic structures, including blood vessels, uriniferous tubules, glomeruli, and renal capsules on a Munich-Wistar rat model. Because the viability of a donor kidney is closely correlated with its tubular morphology, and a large amount of image datasets are expected when using OCT to scan the entire kidney to provide a global assessment of its viability, it is necessary to develop automatic image analysis methods to quantify the spatially-resolved morphometric parameters such as tubular diameter to provide potential diagnostic information. In this study, we imaged the human kidney in vitro and quantified the diameters of hollow structures such as blood vessels and uriniferous tubules automatically. The microstructures were first segmented from cross-sectional OCT images. Then the spatially-isolated region-of-interest (ROI) was automatically selected to quantify its dimension. This method enables the automatic selection and quantification of spatially-resolved morphometric parameters. The quantification accuracy was validated, and measured features are in agreement with known kidney morphology. This work can enable studies to determine the clinical utility of OCT for kidney imaging, as well as studies to evaluate kidney morphology as a biomarker for assessing kidney's viability prior to transplantation.Optics Express 09/2009; 17(18):16000-16. · 3.59 Impact Factor -
Article: Three-dimensional coregistered optical coherence tomography and line-scanning fluorescence laminar optical tomography.
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ABSTRACT: We present a combined optical coherence tomography (OCT) and line-scanning fluorescence laminar optical tomography (FLOT) system. This hybrid system enables coregistered structural and molecular imaging in 3D with 10-100 microm resolution and millimeter-scale imaging depth. Experimental results on a capillary phantom with fluorescence dye Cy5.5 using an OCT/FLOT imaging system have been demonstrated.Optics Letters 07/2009; 34(11):1615-7. · 3.40 Impact Factor -
Article: Optical coherence tomography (OCT) reveals depth-resolved dynamics during functional brain activation.
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ABSTRACT: Optical intrinsic signal imaging (OISI) provides two-dimensional, depth-integrated activation maps of brain activity. Optical coherence tomography (OCT) provides depth-resolved, cross-sectional images of functional brain activation. Co-registered OCT and OISI imaging was performed simultaneously on the rat somatosensory cortex through a thinned skull during forepaw electrical stimulation. Fractional signal change measurements made by OCT revealed a functional signal that correlates well with that of the intrinsic hemodynamic signals and provides depth-resolved, layer-specific dynamics in the functional activation patterns indicating retrograde vessel dilation. OCT is a promising a new technology which provides complementary information to OISI for functional neuroimaging.Journal of Neuroscience Methods 01/2009; 178(1):162-73. · 1.98 Impact Factor -
Conference Proceeding: An Apparel Trade quotation Architecture Based on BPM and SOA.
Pacific Asia Conference on Information Systems, PACIS 2009, Hyderabad, India, July 10-12, 2009; 01/2009 -
Article: Effective treatment of chronic radiation proctitis using radiofrequency ablation.
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ABSTRACT: Endoscopic argon plasma coagulation and bipolar electrocautery are currently preferred treatments for chronic radiation proctitis, but ulcerations and strictures frequently occur. Radiofrequency ablation (RFA) has been successful for mucosal ablation in the esophagus. Here we report the efficacy of RFA with the BarRx Halo(90) system in three patients with bleeding from chronic radiation proctitis. In all cases, the procedure was well tolerated and hemostasis was achieved after 1 or 2 RFA sessions. Re-epithelialization of squamous mucosa was observed over areas of prior hemorrhage. No stricturing or ulceration was seen on follow-up up to 19 months after RFA treatment. Real-time endoscopic optical coherence tomography (EOCT) visualized epithelialization and subsurface tissue microvasculature pre- and post-treatment, demonstrating its potential for follow-up assessment of endoscopic therapies.Therapeutic Advances in Gastroenterology 01/2009; 2(3):149-156. -
Article: Three-dimensional high-resolution optical coherence tomography (OCT) imaging of human kidney.
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ABSTRACT: Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can non-invasively provide cross-sectional, high-resolution images of tissue morphology in situ and in real-time. Previous studies have demonstrated that OCT is capable of accurately visualizing the pathological changes in the living kidney in vivo using the Munich-Wistar rat model. In this work, we establish, for the first time, the capability of OCT to image the intact human kidney ex vivo. Characteristic kidney anatomic structures including the blood vessels, uriniferous tubules, glomeruli, and kidney capsules can be readily discerned. The diameter and volume parameters of these structures can also be automatically quantified. These two parameters may be critical in clinical applications such as the assessment of the donor kidney's viability prior to transplantation, or image the kidney responses to ischemic insult.Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2009; 2009:5741-3. -
Article: High-resolution optical coherence tomography imaging of the living kidney.
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ABSTRACT: Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can provide non-invasive, cross-sectional, high-resolution images of tissue morphology in situ and in real-time. In the present series of studies, we used a high-speed OCT imaging system equipped with a frequency-swept laser light source (1.3 mum wavelength) to study living kidneys in situ. Adult, male Munich-Wistar rats were anesthetized, a laparotomy was performed and the living kidneys were exposed for in situ observation. We observed the kidneys prior to, during and following exposure to renal ischemia induced by clamping the renal artery. The effects of intravenous mannitol infusion (1.0 ml of 25%) prior to and during renal ischemia were also studied. Finally, living kidneys were flushed with a renal preservation solution, excised and observed while being stored at 0-4 degrees C. Three-dimensional OCT data sets enabled visualization of the morphology of the uriniferous tubules and the renal corpuscles. When renal ischemia was induced, OCT revealed dramatic shrinkage of tubular lumens due to swelling of the lining epithelium. Three-dimensional visualization and volumetric rendering software provided an accurate evaluation of volumetric changes in tubular lumens in response to renal ischemia. Observations of kidneys flushed with a renal preservation solution and stored at 0-4 degrees C also revealed progressive and significant loss of tubular integrity over time. Intravenous infusion of mannitol solution resulted in thinning of the tubular walls and an increase in the tubular lumen diameters. Mannitol infusion also prevented the cell swelling that otherwise resulted in shrinkage of proximal tubule lumens during ischemia. We conclude that OCT represents an exciting new approach to visualize, in real-time, pathological changes in the living kidney in a non-invasive fashion. Possible clinical applications are discussed.Laboratory Investigation 05/2008; 88(4):441-9. · 3.64 Impact Factor -
Article: Effects of axial resolution improvement on optical coherence tomography (OCT) imaging of gastrointestinal tissues.
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ABSTRACT: Optical coherence tomography (OCT) is an emerging medical imaging technology which generates high resolution, cross-sectional images in situ, without the need for excisional biopsy. Previous clinical studies using endoscopic OCT with standard 10-15 microm axial resolution have demonstrated its capability in diagnosing Barrett's esophagus (BE) and high-grade dysplasia (HGD). Quantitative OCT image analysis has shown promise for detecting HGD in Barrett's esophagus patients. We recently developed an endoscopic OCT system with an improved axial resolution of approximately 5 microm. The goal in this manuscript is to compare standard resolution OCT and ultrahigh resolution OCT (UHR-OCT) for image quality and computer-aided detection using normal and Barrett's esophagus. OCT images of gastrointestinal (GI) tissues were obtained using UHR-OCT (5.5 microm) and standard resolution OCT (13 microm). Image quality including the speckle size and sharpness was compared. Texture features of endoscopic OCT images from normal and Barrett's esophagus were extracted using quantitative metrics including spatial frequency analysis and statistical texture analysis. These features were analyzed using principal component analysis (PCA) to reduce the vector dimension and increase the discriminative power, followed by linear discrimination analysis (LDA). UHR-OCT images of GI tissues improved visualization of fine architectural features compared to standard resolution OCT. In addition, the quantitative image feature analysis showed enhanced discrimination of normal and Barrett's esophagus with UHR-OCT. The ability of UHR-OCT to resolve tissue morphology at improved resolution enables visualization of subtle features in OCT images, which may be useful in disease diagnosis. Enhanced classification of image features using UHR-OCT promises to help in the computer-aided diagnosis of GI diseases.Optics Express 03/2008; 16(4):2469-85. · 3.59 Impact Factor -
Article: Benign and malignant lesions in the human breast depicted with ultrahigh resolution and three-dimensional optical coherence tomography.
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ABSTRACT: Institutional review board approval at the participating institutions was obtained. Informed consent was waived for this HIPAA-compliant study. The study purpose was to establish the correspondence of optical coherence tomographic (OCT) image findings with histopathologic findings to understand which features characteristic of breast lesions can be visualized with OCT. Imaging was performed in 119 specimens from 35 women aged 29-81 years with 3.5-microm axial resolution and 6-microm transverse resolution at 1.1-microm wavelength on freshly excised specimens of human breast tissue. Three-dimensional imaging was performed in 43 specimens from 23 patients. Microstructure of normal breast parenchyma, including glands, lobules, and lactiferous ducts, and stromal changes associated with infiltrating cancer were visible. Fibrocystic changes and benign fibroadenomas were identified. Imaging of ductal carcinoma in situ, infiltrating cancer, and microcalcifications correlated with corresponding histopathologic findings. OCT is potentially useful for visualization of breast lesions at a resolution greater than that of currently available clinical imaging methods.Radiology 10/2007; 244(3):865-74. · 5.73 Impact Factor -
Article: High-resolution line-scanning optical coherence microscopy.
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ABSTRACT: An optical coherence microscopy system based on line illumination and detection is demonstrated. The system uses a Linnik-type interferometer illuminated by a broadband Ti:sapphire laser and detected by a high-speed, line-scan CCD camera. This approach is less sensitive to incoherent scattering and sample motion than full-field imaging. Spatial resolutions of approximately 2 microm x approximately 3 microm(transverse x axial) are achieved. The sensitivity of the system is 93 dB with averaging over 30 line scans. En face real time, cellular-level imaging of biological tissues is demonstrated at approximately 2 frames/s.Optics Letters 08/2007; 32(14):1971-3. · 3.40 Impact Factor -
Conference Proceeding: Real-Time Imaging of Biological Tissues using High Resolution Line-Scanning Optical Coherence Microscopy
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ABSTRACT: A novel line-scanning optical coherence microscope with 2 mum times 3 mum resolution (transverse times axial), 250 mum times 250 mum field of view, and 90 dB sensitivity is presented for real time, cellular level imaging.Lasers and Electro-Optics, 2007. CLEO 2007. Conference on; 06/2007
Top co-authors
Top Journals
- Optics Express (3)
- Optics Letters (2)
- Laboratory Investigation (2)
- Gastrointestinal Endoscopy (1)
- Radiology (1)
Institutions
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2009–2012
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University of Maryland, College Park
- Department of Electrical & Computer Engineering
College Park, MD, USA
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2010
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Southwest Kidney Institute, PNC
Tucson, AZ, USA
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2005–2009
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Massachusetts Institute of Technology
- Department of Electrical Engineering and Computer Science
Cambridge, MA, USA
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2008
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Georgetown University
- Department of Biochemistry and Molecular and Cellular Biology
Washington, D. C., DC, USA
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