1. Articles in category: Urology

    121-144 of 183 « 1 2 3 4 5 6 7 8 »
    1. Fourier domain versus time domain optical coherence tomography of the prostate nerves

      Fourier domain versus time domain optical coherence tomography of the prostate nerves

      Theoretical comparisons of detection performance for Fourier domain (FD) and time domain (TD) optical coherence tomography (OCT) have been previously reported. In this study, we compare several image quality metrics including signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and equivalent number of looks (ENL) for TD-OCT and FD-OCT images taken of the rat prostate, in vivo. The results show that TD-OCT has inferior CNR, but superior SNR compared to FD-OCT, and that TD-OCT is better for deep imaging of opaque tissues, including the prostate gland.

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    2. Feature Of The Week 2/6/11: Investigation into using Optical Coherence Tomography for Grading Urothelial Carcinoma - Recent Work from Academic Medical Center Amsterdam and University of Twente

      Feature Of The Week 2/6/11: Investigation into using Optical Coherence Tomography for Grading Urothelial Carcinoma - Recent Work from Academic Medical Center Amsterdam and University of Twente
      Feature Of The Week 2/6/11: Achieving the goal of a real-time in-situ high-resolution optical biopsy using OCT would be a tremendous boost to medicine and mankind. However is it quite a complex and difficult challenge that has not been fully realized to date. Many people believe this challenge will be realized in the not too distant future as understanding, approaches, and technology is improved due to progress at various prestigious research institutions around the world. Below is a review of some recent work from such institutions - the Academic Medical Center Amsterdam and the University of Twente.IntroductionReal-time grading ...
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    3. Three-Dimensional Imaging of Ureter With Endoscopic Optical Coherence Tomography

      Three-Dimensional Imaging of Ureter With Endoscopic Optical Coherence Tomography
      Objectives To verify the ability to identify the layered structures of the ureteral wall and to image a segment of the ureter in 3 dimensions with high-speed, endoscopic optical coherence tomography (EOCT). Methods We imaged a porcine ureter ex vivo using a spectral-domain EOCT with a specially designed circumferential scanning fiber catheter. The images were correlated with the histologic findings to identify the corresponding structures. Three-dimensional images and en face images at different depths from the luminal surface were reconstructed from the multiple cross-sectional images to visualize the layered structure of a segment of the ureter from different perspectives. Results ...
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    4. Advanced Diagnostics in Renal Mass Using Optical Coherence Tomography: A Preliminary Report

      Advanced Diagnostics in Renal Mass Using Optical Coherence Tomography: A Preliminary Report
      Objective: To avoid unnecessary surgical treatment of small renal masses (≤4cm), a more accurate diagnostic method would be desirable since radiological differentiation between malignant and benign is difficult and nondiagnostic biopsies account from 9% to 37%. Optical coherence tomography (OCT) measures backscattered light versus depth, with an attenuation coefficient (μt) that may vary among different histological types. We hypothesize that quantitative measurements of μt using OCT can differentiate between normal renal parenchyma and renal cell carcinoma (RCC). Materials and Methods: Both normal and tumor renal tissues (RCC) were harvested after partial or radical nephrectomy. Analysis of μt was based on ...
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    5. Quantitative measurement of attenuation coefficients of bladder biopsies using optical coherence tomography for grading urothelial carcinoma of the bladder

      Quantitative measurement of attenuation coefficients of bladder biopsies using optical coherence tomography for grading urothelial carcinoma of the bladder
      Real-time grading of bladder urothelial carcinoma (UC) is clinically important, but the current standard for grading (histopathology) cannot provide this information. Based on optical coherence tomography (OCT)-measured optical attenuation (µt), the grade of bladder UC could potentially be assessed in real time. We evaluate ex vivo whether µt differs between different grades of UC and benign bladder tissue. Human bladder tissue specimens are examined ex vivo by 850-nm OCT using dynamic focusing. Three observers independently determine the µt from the OCT images, and three pathologists independently review the corresponding histology slides. For both methods, a consensus diagnosis is made ...
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    6. Cross-polarization optical coherence tomography for early bladder-cancer detection: statistical study

      Cross-polarization optical coherence tomography for early bladder-cancer detection: statistical study
      The capabilities of cross-polarization optical coherence tomography (CP OCT) for early bladder-cancer detection are assessed in statistical study and compared with the traditional OCT. Unlike the traditional OCT that demonstrates images only in copolarization, CP OCT acquires images in cross-polarization and copolarization simultaneously. 116 patients with localized flat suspicious lesions in the bladder were enrolled, 360 CP OCT images were obtained and analyzed. CP OCT demonstrated sensitivity 93.7% (vs. 81.2%, <0.0001), specificity 84% (vs. 70.0%, <0.001) and accuracy 85.3% (vs. 71.5%, <0.001) in detecting flat malignant bladder lesions, which is significantly better ...
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    7. Feature Of The Week 10/3/10: Combined Image-Processing Algorithms for Improved OCT Imaging of Prostate Nerves

      Feature Of The Week 10/3/10: Combined Image-Processing Algorithms for Improved OCT Imaging of Prostate Nerves
      Feature Of The Week 10/3/10: The cavernous nerves are responsible for sexual function. These nerves are at risk of injury during surgical dissection and removal of a cancerous prostate gland because of the close proximity of the nerves to the prostate surface. Their microscopic nature also makes it difficult to predict the true course and location of these nerves from one patient to another. These observations may explain in part the wide variability in reported potency rates (9-86%) following prostate cancer surgery. Therefore, any technology capable of providing improved identification, imaging, and visualization of the cavernous nerves during ...
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    8. Combined image-processing algorithms for improved optical coherence tomography of prostate nerves

      Combined image-processing algorithms for improved optical coherence tomography of prostate nerves
      Cavernous nerves course along the surface of the prostate gland and are responsible for erectile function. These nerves are at risk of injury during surgical removal of a cancerous prostate gland. In this work, a combination of segmentation, denoising, and edge detection algorithms are applied to time-domain optical coherence tomography (OCT) images of rat prostate to improve identification of cavernous nerves. First, OCT images of the prostate are segmented to differentiate the cavernous nerves from the prostate gland. Then, a locally adaptive denoising algorithm using a dual-tree complex wavelet transform is applied to reduce speckle noise. Finally, edge detection is ...
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    9. Enhancing Detection of Bladder Carcinoma In Situ by 3-Dimensional Optical Coherence Tomography

      Enhancing Detection of Bladder Carcinoma In Situ by 3-Dimensional Optical Coherence Tomography
      Purpose: We examined the usefulness of 3-dimensional optical coherence tomography to enhance the diagnosis of urothelial carcinoma in situ.Materials and Methods: By expressing SV40T antigen with uroplakin II promoter, carcinoma in situ readily develops in SV40T transgenic mice at about ages 8 to 20 weeks and then frank high grade papillary carcinoma develops in bladder epithelium. We examined 10 control and 40 SV40T mice during weeks 8 to 20 after birth by parallel en face white light imaging and 3-dimensional optical coherence tomography, and compared results with histology findings. We applied quantitative analysis of computer aided detection to 3-dimensional ...
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    10. The origins of urothelial carcinoma

      The origins of urothelial carcinoma
      Expert Review of Anticancer Therapy , June 2010, Vol. 10, No. 6, PaIt is now widely believed that there are two major pathways for urothelial carcinogenesis. One pathway usually involves mutation of FGF receptor 3 and gives rise to low-grade papillary tumors that frequently recur but seldom invade. By contrast, high-grade urothelial malignancies, including high-grade papillary urothelial carcinoma and urothelial carcinoma in situ (CIS) usually exhibit deletions or mutations of TP53. Urothelial CIS is the most likely precursor of high-grade invasive bladder cancer. It is a ‘flat lesion’ that may be relatively inconspicuous at cystoscopy, or even endoscopically undetectable. The clinical ...
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    11. Exclusive report from the International Society for the Study of Bladder Pain Syndrome (ESSIC) 8th Annual Meeting

      Exclusive report from the International Society for the Study of Bladder Pain Syndrome (ESSIC) 8th Annual Meeting
      Dr. Zaitcev from Moscow discussed a new tool that may help to identify the bladder lesions of BPS. He used optical coherence tomography in 21 women with Hunner’s lesions who underwent bladder distention under anesthesia. Optical coherence tomography is a novel method that can be used to construct cross-sectional images of tissue microstructure with high spatial resolution. It measures optical scattering of light by comparing the backscattered or back reflected light signal to a controlled reference signal. The principle is similar to B-mode ultrasound, except light is the medium rather than sound. In all cases, optical coherence tomograpy allowed ...
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    12. Tissue-mimicking bladder wall phantoms for evaluating acoustic radiation force-optical coherence elastography systems

      Tissue-mimicking bladder wall phantoms for evaluating acoustic radiation force-optical coherence elastography systems
      Purpose: Acoustic radiation force–optical coherence elastography (ARF-OCE) systems are novel imaging systems that have the potential to simultaneously quantify and characterize the optical and mechanical properties of in vivo tissues. This article presents the construction of bladder wall phantoms for use in ARF-OCE systems. Mechanical, acoustic, and optical properties are reported and compared to published values for the urinary bladder. Methods: The phantom consisted of 0.2000±0.0089 and 6.0000±0.2830 µm polystyrene microspheres (Polysciences Inc., Warrington, PA, Catalog Nos. 07304 and 07312), 7.5±1.5 µm copolymer microspheres composed of acrylonitrile and vinylidene chloride ...
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    13. Optical Coherence Tomography of Human Kidney

      Optical Coherence Tomography of Human Kidney
      Purpose 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 μm 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. Materials and Methods Using a high speed optical coherence tomography system equipped with a ...
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    14. Optical Coherence Tomography in the Kidney: A Step Toward Echo Microscopy

      Optical Coherence Tomography in the Kidney: A Step Toward Echo Microscopy
      Optical coherence tomography (OCT) can present noninvasive cross-sectional images of internal tissue microstructure by measuring their optical reflections of a light beam of super luminescent diodes. Recently, swept laser has been used as a light source and has achieved high speed and resolution images with 1 to 15 μm resolution. The high resolution OCT imaging is performed in a way similar to the ultrasonic echo imaging but it uses the echo of lasers with extremely short pulses (femtosecond lasers) with 100 times finer resolution than ultrasound echo, so that OCT can be a step toward the development of laser echo ...
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    15. Advantages of cross-polarization endoscopic optical coherence tomography in diagnosis of bladder neoplasia

      Advantages of cross-polarization endoscopic optical coherence tomography in diagnosis of bladder neoplasia
      We consider the cross-polarization OCT (CP OCT) that is focused on comparison of images resulting from cross-polarization and co-polarization scattering simultaneously. This technique provides information about microstructural and biochemical alterations in depolarizing tissue components (collagen). We found that mature type I collagen gives a strong signal in orthogonal polarization. CP OCT images of benign inflammatory processes always feature signal in orthogonal polarization, with layers and borders persisting to be well defined. In the presence of precancerous alterations, signal in orthogonal polarization is available in the image but it is irregular, disappearing in some areas. A CP OCT image of bladder ...
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    16. Near-IR optical properties of canine prostate tissue using oblique-incidence reflectometry

      Near-IR optical properties of canine prostate tissue using oblique-incidence reflectometry
      Optical imaging systems utilizing near-infrared light sources such as optical coherence tomography (OCT) have recently been used for imaging the prostate gland. However, the optimal wavelength for deep imaging of the prostate has yet to be determined. The objective of this study is to determine the optimal near-infrared wavelength for OCT imaging of the prostate using a system that has the potential to be used in an in vivo model. An obliqueincidence single point measurement technique using a normal-detector scanning system was implemented to determine the absorption (µa) and reduced scattering coefficients (µ's) of fresh canine prostate tissue, ex ...
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    17. Plasmon resonance gold nanoparticles for improving optical diagnostics and photothermal therapy of tumor

      Plasmon resonance gold nanoparticles for improving optical diagnostics and photothermal therapy of tumor
      The study was performed on 16 CBA-line female mice with transplanted cervical cancer. 0.2 ml of gold nanoparticle solution with a concentration of 109 particles/ml were injected into the animals intravenously. The particles were 200-250 nm in size; the plasmon-resonance related extinction maximum was at the wavelength of 850-950 nm. Accumulation of the nanoparticles into tumor node was visualized by the method of optical coherence tomography (OCT). When the accumulation of nanoparticles in the tumor was maximal, hyperthermia was accomplished using the LSP-AZOR laser setup generating cw radiation at 810 nm. The duration of exposition was 20 min ...
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    18. Optical coherence tomography of the upper urinary tract: Review of initial experience ex vivo and in vivo

      Optical coherence tomography of the upper urinary tract: Review of initial experience ex vivo and in vivo
      Diagnostic imaging of the upper urinary tract is a cumbersome process that involves a multitude of different imaging modalities, including ultrasonography, conventional radiography, X-ray fluoroscopy (retrograde and antegrade ureteropyelography), endoscopy (cystoscopy and ureterorenoscopy) without or with biopsy, multi-detector-row computed tomography (MDCT), and magnetic resonance imaging (MRI). However, these modalities leave a diagnostic gap because they cannot demonstrate different layers of the wall of the upper urinary tract. Recent research shows that catheter-based, intraluminal probes for optical coherence tomography (OCT) with near-infrared light provide cross-sectional images from within the lumen of the upper urinary tract that distinguish between the urothelium, lamina ...
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    19. Bladder cancer: Optical coherence tomography improves UCC detection

      Targeted optical coherence tomography (OCT) in combination with hexaminolevulinate (HAL) fluorescence cystoscopy improves diagnostic accuracy in detecting urothelial cell carcinoma (UCC) of the bladder, report Schmidbauer and colleagues from the Medical University of Vienna.Fluorescence cystoscopy has been shown to significantly improve detection of UCC when used as an adjunct to white-light cystoscopy.
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    20. On the possibility of time-lapse ultrahigh-resolution optical coherence tomography for bladder cancer grading

      has been recently demonstrated that the cellular details of bladder epithelium embedded in speckle noise can be uncovered with time-lapse ultrahigh-resolution optical coherence tomography (TL-uOCT) by proper time-lapse frame averaging that takes advantage of cellular micromotion in fresh biological tissue ex vivo. Here, spectral-domain 3-D TL-uOCT is reported to further improve the image fidelity, and new experimental evidence is presented to differentiate normal and cancerous nuclei of rodent bladder epithelia. Results of animal cancer study reveal that despite a slight overestimation (e.g., <10%) of nuclear size (DN) to histological evaluation, TL-uOCT is capable of distinguishing normal (DN7 µm) and ...
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    21. Segmentation of optical coherence tomography images for differentiation of the cavernous nerves from the prostate gland

      Segmentation of optical coherence tomography images for differentiation of the cavernous nerves from the prostate gland
      The cavernous nerves course along the surface of the prostate and are responsible for erectile function. Improvements in identification, imaging, and visualization of the cavernous nerves during prostate cancer surgery may improve nerve preservation and postoperative sexual potency. Two-dimensional (2-D) optical coherence tomography (OCT) images of the rat prostate were segmented to differentiate the cavernous nerves from the prostate gland. To detect these nerves, three image features were employed: Gabor filter, Daubechies wavelet, and Laws filter. The Gabor feature was applied with different standard deviations in the x and y directions. In the Daubechies wavelet feature, an 8-tap Daubechies orthonormal ...
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    22. Impact of renal function on coronary plaque composition

      Background. Recent studies have demonstrated that patients with chronic kidney disease are at high risk of atherosclerosis. Recently it has been found that coronary plaque components can be evaluated by integrated backscatter intravascular ultrasound (IB-IVUS), and lipid-rich plaque is associated with vulnerable plaque. The aim of the study was to investigate the relationship between renal function and tissue characterization of coronary plaque composition at the target stenotic site for percutaneous coronary intervention (PCI). Methods. We prospectively performed IB-IVUS before elective PCI in 89 consecutive patients with stable angina. According to estimated glomerular filtration rate (eGFR), they were divided into two ...
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    23. Optical coherence tomography: a novel modality for scrotal imaging

      Optical coherence tomography: a novel modality for scrotal imaging
      Background: For patients with nonobstructive azoospermia, sperm retrieval rates remain modest. We describe the use of optical coherence tomography to improve retrieval rates and to decrease tissue destruction. Methods: Four patients underwent diagnostic testicular biopsy and imaging with the Niris optical coherence tomography de - vice. We performed a descriptive comparison between optic al coherence tomographic images and conventional histology. Results: The measured seminiferous tubule diameter differed by 16 μm between comparative imaging from optical coherence tomography and conventional histology using hematoxylin and eosin staining. Conclusion: We illustrate the usefulness of optical coherence tomography in the setting of testicular biopsy and ...
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