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    1. Evaluation of IVOCT imaging of coronary artery metallic stents with neointimal coverage

      Evaluation of IVOCT imaging of coronary artery metallic stents with neointimal coverage

      Accuracy of IVOCT for measurement of neointimal thickness and effect of neointima in the appearance of metallic struts in IVOCT images was investigated. Phantom vessels were constructed and coronary stents were deployed and covered with thick (250–400 μm) and thin (30–70 μm) phantom neointima. High resolution Micro-CT images of the stent struts were recorded as a gold standard. IVOCT images of the phantom vessels were acquired with various luminal blood scattering strengths and measured neointimal thicknesses from IVOCT and Micro-CT images were compared. In transparent lumen, comparison of IVOCT and Micro-CT neointima thickness measurements found no significant difference ...

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    2. In vitro assessment of effects of hyperglycemia on the optical properties of blood during coagulation using optical coherence tomography

      In vitro assessment of effects of hyperglycemia on the optical properties of blood during coagulation using optical coherence tomography

      No published reports have demonstrated the capability of the optical coherence tomography technique for quantifying the optical coherence tomography signal slope, 1/e light penetration depth, and attenuation coefficient of hyperglycemic blood by an in vitro assessment. The purpose of this study was to investigate the effects of hyperglycemia on optical properties during in vitro blood coagulation by optical coherence tomography. Normal whole blood acted as the control group. After 1-h coagulation, the average optical coherence tomography signal slope decreased approximately 23.3 and 16.7 %, and the 1/e light penetration depths increased approximately 21.5 and 19.2 ...

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    3. Application of Improved Homogeneity Similarity-Based Denoising in Optical Coherence Tomography Retinal Images

      Application of Improved Homogeneity Similarity-Based Denoising in Optical Coherence Tomography Retinal Images

      Image denoising is a fundamental preprocessing step of image processing in many applications developed for optical coherence tomography (OCT) retinal imaging—a high-resolution modality for evaluating disease in the eye. To make a homogeneity similarity-based image denoising method more suitable for OCT image removal, we improve it by considering the noise and retinal characteristics of OCT images in two respects: (1) median filtering preprocessing is used to make the noise distribution of OCT images more suitable for patch-based methods; (2) a rectangle neighborhood and region restriction are adopted to accommodate the horizontal stretching of retinal structures when observed in OCT ...

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    4. Optical coherence tomography shows early loss of the inferior temporal quadrant retinal nerve fiber layer in autosomal dominant optic atrophy

      Optical coherence tomography shows early loss of the inferior temporal quadrant retinal nerve fiber layer in autosomal dominant optic atrophy

      Purpose The aim of the study was to evaluate the relationship between visual function and retinal nerve fiber layer thickness (RNFLT) determined using Stratus optical coherence tomography (OCT) in patients with autosomal dominant optic atrophy (ADOA). Methods The study was a retrospective, institutional, and comparative case series. Thirty-six consecutive patients with ADOA and 72 age-matched normal controls were compared with regard to RNFLT, best-corrected visual acuity (BCVA), and visual field. Results The relative reduction of RNFLT of ADOA patients was most evident in the temporal quadrant (56.8 %), followed by the inferior (35.5 %), superior (27.2 %), and nasal quadrants ...

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    5. Microanatomy of the tympanic membrane in chronic myringitis obtained with optical coherence tomography

      Microanatomy of the tympanic membrane in chronic myringitis obtained with optical coherence tomography

      A microscope-based optical coherence tomography (OCT) device was used to assess the microanatomy of the tympanic membrane in patients with chronic myringitis. A prospective study was designed for this purpose. OCT measurements of the tympanic membrane were done on 11 patients with myringitis with a microscope-based spectral domain OCT system. The in vivo findings were compared with those findings of a control group consisting of 36 patients with retraction pockets or atrophic tympanic membranes ( n = 13), myringosclerosis ( n = 12) and perforations ( n = 11). In active chronic myringitis, the thickness of the tympanic membrane is increased compared to healthy membranes and ...

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    6. The impact of multifocal intraocular lens in retinal imaging with optical coherence tomography

      The impact of multifocal intraocular lens in retinal imaging with optical coherence tomography

      Multifocal intraocular lenses (MF IOLs) have concentric optical zones with different dioptric power, enabling patients to have good visual acuity at multiple focal points. However, several optical limitations have been attributed to this particular design. The purpose of this study is to access the effect of MF IOLs design on the accuracy of retinal optical coherence tomography (OCT). Cross-sectional study conducted at the Refractive Surgery Department of Central Lisbon Hospital Center. Twenty-three eyes of 15 patients with a diffractive MF IOL and 27 eyes of 15 patients with an aspheric monofocal IOL were included in this study. All patients underwent ...

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    7. Innovations in Microscopic Imaging of Atherosclerosis and Valvular Disease (Book Chapter)

      Innovations in Microscopic Imaging of Atherosclerosis and Valvular Disease (Book Chapter)

      Calcific aortic valve disease (CAVD) is still an unsolved medical problem, because the pathogenesis of CAVD is poorly understood and early calcification is hard to identify. The lack of high-resolution imaging tools to study early stage disease further hampers the search for therapeutic targets. Micro-optical coherence tomography (μOCT), which is a new form of OCT, is the highest-resolution cross-sectional OCT technology available today with 1 μm resolution. We used μOCT to visualize detailed cellular and subcellular structure associated with early calcific changes in diseased human and murine aortic valves. The results suggest that μOCT imaging has the potential to provide ...

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    8. Difference in correspondence between visual field defect and inner macular layer thickness measured using three types of spectral-domain OCT instruments

      Difference in correspondence between visual field defect and inner macular layer thickness measured using three types of spectral-domain OCT instruments

      Purpose To compare the relationship between visual field sensitivity (VFS) and macular parameters measured using three spectral-domain optical coherence tomography (SD-OCT) instruments and to determine a base level (=floor effect) for macular parameters. Methods We imaged 127 glaucomatous eyes (1 eye per subject) using three different OCT instruments, i.e., the Cirrus , RTVue and 3D OCT devices; 76 normal eyes were evaluated as controls using the same instruments. The thicknesses of the macular retinal nerve fiber layer (mRNFL), ganglion cell layer+inner plexiform layer (GCL/IPL), and mRNFL+GCL/IPL (GCC) were analyzed. The VFS of the area analyzed by ...

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    9. Enhanced depth imaging-OCT of the choroid: a review of the current literature

      Enhanced depth imaging-OCT of the choroid: a review of the current literature

      Background With the advent of enhanced depth imaging optical coherence tomography (EDI-OCT), detailed visualisation of the choroid in vivo is now possible. Measurements of choroidal thickness (CT) have also enabled new directions in research to study normal and pathological processes within the choroid. The aim of the present study is to review the current literature on choroidal imaging using EDI-OCT. Methods Studies were identified by a systematic search using Medline ( http://www.ncbi.nlm.nih.gov/pubmed ). Papers were also identified based on the reference lists of relevant publications. Papers were included in the review if the focus of the ...

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    10. Neointimal coverage of zotarolimus-eluting stent at 1, 2, and 3 months' follow-up: an optical coherence tomography study

      Neointimal coverage of zotarolimus-eluting stent at 1, 2, and 3 months' follow-up: an optical coherence tomography study

      Incomplete neointimal coverage and malapposed struts after stenting are associated with increased risk of stent thrombosis. We aimed to evaluate neointimal coverage early after Resolute zotarolimus-eluting stent (R-ZES) implantation using optical coherence tomography (OCT). A total of 20 patients with de novo native coronary lesions with R-ZES were enrolled. Among these patients, 20 stented lesions in 19 patients were evaluated at 1, 2, and 3 months after R-ZES implantation. The strut apposition and neointimal coverage were evaluated by OCT. Neointimal hyperplasia (NIH) thickness and percentage of covered struts and the proportion of incompletely apposed struts were measured at 1-mm intervals ...

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    11. Analysis of Linear Anisotropic Parameters by Using Hybrid Model in Mueller Optical Coherence Tomography

      Analysis of Linear Anisotropic Parameters by Using Hybrid Model in Mueller Optical Coherence Tomography

      This study proposes a Mueller optical coherence tomography (OCT) to extract linear birefringence (LB), linear dichroism (LD) parameters in the optically anisotropic material. The full 4 × 4 Mueller matrix of the sample is able to be measured by the Mueller OCT. Hence, a hybrid model based on the Mueller matrix derived by the differential Mueller matrix formalism and both considering the forward and backward measured beams for an anisotropic sample containing LB and LD is developed to obtain corresponding anisotropic parameters in OCT system. In contrast to the conventional polarization-sensitive OCT only for LB measurement and Mueller OCT only for ...

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    12. Lipid-rich plaque in possible coronary sequelae of Kawasaki disease detected by optical frequency domain imaging

      Lipid-rich plaque in possible coronary sequelae of Kawasaki disease detected by optical frequency domain imaging

      Potential risk for early development of atherosclerosis in patients with antecedent- Kawasaki disease (KD) is now attracting more attention. A 47-year-old man was admitted to our hospital because of calcification exclusively in the proximal segment of left anterior descending coronary artery (LAD) on chest CT. Coronary CT revealed a severe stenosis at the inlet of the aneurysm with eggshell-like calcification in the proximal LAD, highly suspecting the presence of coronary sequelae of KD. During the rotational atherectomy-based interventional procedure, optical frequency domain imaging, a new generation of optical coherence tomography, clearly depicted lipid deposition in the culprit lesion.

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    13. Comparison of multifocal visual evoked potential, static automated perimetry, and optical coherence tomography findings for assessing visual pathways in patients with pituitary adenomas

      Comparison of multifocal visual evoked potential, static automated perimetry, and optical coherence tomography findings for assessing visual pathways in patients with pituitary adenomas

      Background There have been no studies investigating the correlation between structural [thickness of the retinal nerve fiber layer (RNFL) as determined by optical coherence tomography (OCT)] and functional [Humphrey visual field (HVF) or visual evoked potential (VEP) amplitude] measures of optic nerve integrity in patients with pituitary adenomas (PA). Methods Patients with PAs were recruited between September 2010 and September 2013. OCT, standard automated perimetry (SAP), and multifical VEP (mfVEP) were performed. Agreement between OCT, SAP, and mfVEP values in classifying eyes/quadrants was determined using AC1 statistics. Pearson’s correlation was used to examine relationships between structural and functional ...

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      Mentions: Fudan University
    14. Dual modality intravascular optical coherence tomography (OCT) and near-infrared fluorescence (NIRF) imaging: a fully automated algorithm for the distance-calibration of NIRF signal intensity for quantitative molecular imaging

      Dual modality intravascular optical coherence tomography (OCT) and near-infrared fluorescence (NIRF) imaging: a fully automated algorithm for the distance-calibration of NIRF signal intensity for quantitative molecular imaging

      Intravascular optical coherence tomography (IVOCT) is a well-established method for the high-resolution investigation of atherosclerosis in vivo. Intravascular near-infrared fluorescence (NIRF) imaging is a novel technique for the assessment of molecular processes associated with coronary artery disease. Integration of NIRF and IVOCT technology in a single catheter provides the capability to simultaneously obtain co-localized anatomical and molecular information from the artery wall. Since NIRF signal intensity attenuates as a function of imaging catheter distance to the vessel wall, the generation of quantitative NIRF data requires an accurate measurement of the vessel wall in IVOCT images. Given that dual modality, intravascular ...

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    15. Optical Coherence Tomography: OCT (Book Chapter)

      Optical Coherence Tomography: OCT (Book Chapter)

      Optical coherence tomography (OCT) allows to measure geometric features inside translucent objects such as organic materials or organic tissues. The principle is based on interferometry. Time-domain and Fourier-domain methods are applied to make visible differences in the refractive index profile of the measuring object. We present the set-up of OCT sensors and show examples of applications such as 3D-imaging of an eye, B-scans of blood vessels or thickness measurements of multi-layer polymer films.

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    16. Automated 3D segmentation of multiple surfaces with a shared hole: segmentation of the neural canal opening in SD-OCT volumes

      Automated 3D segmentation of multiple surfaces with a shared hole: segmentation of the neural canal opening in SD-OCT volumes

      The need to segment multiple interacting surfaces is a common problem in medical imaging and it is often assumed that such surfaces are continuous within the confines of the region of interest. However, in some application areas, the surfaces of interest may contain a shared hole in which the surfaces no longer exist and the exact location of the hole boundary is not known a priori . The boundary of the neural canal opening seen in spectral-domain optical coherence tomography volumes is an example of a “hole” embedded with multiple surrounding surfaces. Segmentation approaches that rely on finding the surfaces alone ...

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    17. Speckle Reduction in Optical Coherence Tomography by Image Registration and Matrix Completion

      Speckle Reduction in Optical Coherence Tomography by Image Registration and Matrix Completion

      Speckle noise is problematic in optical coherence tomography (OCT). With the fast scan rate, swept source OCT scans the same position in the retina for multiple times rapidly and computes an average image from the multiple scans for speckle reduction. However, the eye movement poses some challenges. In this paper, we propose a new method for speckle reduction from multiply-scanned OCT slices. The proposed method applies a preliminary speckle reduction on the OCT slices and then registers them using a global alignment followed by a local alignment based on fast iterative diamond search. After that, low rank matrix completion using ...

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    18. Fabrication method of ultra-small gradient-index fiber probe

      Fabrication method of ultra-small gradient-index fiber probe

      Fabrication method and device of ultra-small gradient-index (GRIN) fiber probe were investigated in order to explore the development of ultra-small probes for optical coherence tomography (OCT) imaging. The beam-expanding effect of no-core fiber (NCF) and the focusing properties of the GRIN fiber lens were analyzed based on the model of GRIN fiber probe consisting of single-mode fiber (SMF), NCF and GRIN fiber lens. A stereo microscope based system was developed to fabricate the GRIN fiber probe. A fiber fusion splicer and an ultrasonic cleaver were used to weld and cut the fiber respectively. A confocal microscopy was used to measure ...

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    19. Evolution of vitreomacular adhesion to acute vitreofoveal separation with special emphasis on a traction-induced foveal pathology. A prospective study of spectral-domain optical coherence tomography

      Evolution of vitreomacular adhesion to acute vitreofoveal separation with special emphasis on a traction-induced foveal pathology. A prospective study of spectral-domain optical coherence tomography

      Purpose To investigate the evolution of vitreomacular adhesion (VMA) to acute vitreofoveal separation with particular emphasis on cases involving the underlying fovea. Methods In this observational case series, of 192 cases in the VMA stage, 51 progressed to acute vitreofoveal separation; this subgroup was divided into those with normal separation (Group I) and those with co-existing macular findings (Group II). All patients were examined using spectral domain-optical coherence tomography (SD-OCT) at regular three-month intervals. We recorded the best-corrected visual acuity (BCVA), the vitreomacular angle of the VMA (nasally and temporally), the horizontal diameter of the VMA, the macular thickness, the ...

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    20. Diagnosis of subretinal neovascularization associated with idiopathic juxtafoveal retinal telangiectasia — fluorescein angiography versus spectral-domain optical coherence tomography — can we choose?

      Diagnosis of subretinal neovascularization associated with idiopathic juxtafoveal retinal telangiectasia — fluorescein angiography versus spectral-domain optical coherence tomography — can we choose?

      Dear Editor We read with great interest the article entitled ”Diagnosis of subretinal neovascularization associated with idiopathic juxtafoveal retinal telangiectasia—fluorescein angiography versus spectral-domain optical coherence tomography by Chhablani J et al. [ 1 ]. This article compares the ability of fundus fluorescein angiography (FFA) and spectral-domain optical coherence tomography (SD-OCT) to diagnose subretinal neovascularization (SRNV) secondary to idiopathic juxtafoveal retinal telangiectasia (IJRT) type 2A, and also highlights the pitfalls of FFA and OCT in detecting and confirming SRNV in cases of IJRT type 2. However we have made the following observations

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    21. Comparison of morphologic findings obtained by optical coherence tomography in acute coronary syndrome caused by vasospasm and chronic stable variant angina

      Comparison of morphologic findings obtained by optical coherence tomography in acute coronary syndrome caused by vasospasm and chronic stable variant angina

      This study used optical coherence tomography (OCT) to evaluate morphologic changes in vasospastic lesions, which can cause acute coronary syndrome (ACS) or chronic stable VA. Thirty-nine patients (52.4 ± 9.0 years, 33 males) with vasospasm-induced ACS who presented with chest pain and displayed transient ST segment elevation on electrocardiography were included in the ACS group. Forty-one patients (49.3 ± 7.7 years, 33 males) who presented with chronic stable variant angina were included in the VA group. The clinical characteristics and morphologic OCT results of the two groups were compared. There were no differences in baseline characteristics, including the ...

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    22. Optical Coherence Tomography and Cryosurgery (Book Chapter)

      Optical Coherence Tomography and Cryosurgery (Book Chapter)

      Optical coherence tomography (OCT) provides real-time, cross-sectional skin images to a depth of up to 2 mm. OCT is a convenient and fast imaging technology that can be used bedside. In dermatology, the pretherapeutic delineation of both actinic keratoses (AK) and keratinocyte carcinomas has been a natural focus for applied OCT research, and more recently OCT research has turned on non-invasive monitoring of treatments. Previous studies have found good agreement between OCT images and histopathological images. Cryotherapy is a fast and easy treatment modality frequently used for the treatment of AK lesions in everyday dermatology practise. Cryosurgery with liquid nitrogen ...

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    23. Frequency and predictors of thrombus inside the guiding catheter during interventional procedures: an optical coherence tomography study

      Frequency and predictors of thrombus inside the guiding catheter during interventional procedures: an optical coherence tomography study

      Optical coherence tomography (OCT) is able to identify thrombus. We detect the frequency of thrombus inside the guiding catheter by OCT and its relationship with clinical and procedural factors. We screened 77 patients who underwent OCT pullbacks. Only patients with visible guiding catheter were finally included (35) and divided into thrombus (21) or no-thrombus group (14). Patients within thrombus group were mostly males (100 vs. 71 %, p = 0.05), with acute coronary syndrome (76 vs. 36 %, p = 0.02) and received more frequently percutaneous coronary intervention (86 vs. 43 %, p = 0.01) as compared to other group. A second dose ...

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    24. A comparison of tissue prolapse with optical coherence tomography and intravascular ultrasound after drug-eluting stent implantation

      A comparison of tissue prolapse with optical coherence tomography and intravascular ultrasound after drug-eluting stent implantation

      The aim of this study was to compare the detection rate of tissue prolapse (TP) in optical coherence tomography (OCT) and intravascular ultrasound (IVUS) after drug-eluting stent (DES) implantation and evaluate clinical implication of TP at 2 years after percutaneous coronary intervention. In spite of the superiority of OCT in the aspect of resolution when it was compared to IVUS, there was little data about the superiority of OCT in detecting TP. And there has been controversy about the clinical significance of TP. We enrolled 38 patients who treated with DES implantation. OCT and IVUS measurements were performed in stented ...

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