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    1. Optical coherence tomography-based patient-specific coronary artery reconstruction and fluid–structure interaction simulation

      Optical coherence tomography-based patient-specific coronary artery reconstruction and fluid–structure interaction simulation

      Plaque rupture is related to the mechanical stress it suffered. The value and distribution of the mechanical stress in plaque could help on assessing plaque vulnerability. To look into the stress conditions in the coronary artery, a patient-specific coronary model was created by using optical coherence tomography (OCT) and angiography imaging data. The reconstructed coronary model consisted of the structure of the lumen, the arterial wall and plaque components. Benefited by the high resolution of OCT, detailed structures such as the thin fibrous cap could be observed and built into the geometry. On this reconstructed coronary model, a fully coupled ...

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    2. Comparison of conjunctival vascularity changes using optical coherence tomography angiography after trabeculectomy and phacotrabeculectomy

      Comparison of conjunctival vascularity changes using optical coherence tomography angiography after trabeculectomy and phacotrabeculectomy

      Purpose To compare bleb vascularity changes using optical coherence tomography angiography (OCT-A) between mitomycin-C (MMC)-augmented trabeculectomy and phacotrabeculectomy and to determine whether bleb vascularity measurements during preoperative and early postoperative periods could act as surrogate parameters to predict surgical outcomes. Methods We retrospectively reviewed data for 72 eyes from 72 glaucoma patients who underwent MMC-augmented trabeculectomy with/without cataract surgery. Bleb area scans were obtained using OCT-A during the preoperative period; 1, 2, 4, and 6 weeks postoperatively; and 2, 4, and 6 months postoperatively. For conjunctival vascularity analysis, a semi-automated program was used to calculate color and brightness ...

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    3. Retinal Optical Coherence Tomography Image Analysis

      Retinal Optical Coherence Tomography Image Analysis

      This book introduces the latest optical coherence tomography (OCT) imaging and computerized automatic image analysis techniques, and their applications in the diagnosis and treatment of retinal diseases. Discussing the basic principles and the clinical applications of OCT imaging, OCT image preprocessing, as well as the automatic detection and quantitative analysis of retinal anatomy and pathology, it includes a wealth of clinical OCT images, and state-of-the-art research that applies novel image processing, pattern recognition and machine learning methods to real clinical data. It is a valuable resource for researchers in both medical image processing and ophthalmic imaging.

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    4. Analysis of retinal nerve fiber layer thickness in anisometropic amblyopia via optic coherence tomography

      Analysis of retinal nerve fiber layer thickness in anisometropic amblyopia via optic coherence tomography

      Objective To detect retinal nerve fiber layer thickness differences of ambylopic and fellow eyes and ambylopic and control eyes. Methods The study comprised a total of 152 eyes recruited from Erzurum Region Training and Research Hospital, Turkey, between January 2018 and May 2018. Anisometropic amblyopia was the only cause of disability (visual acuity ≤ 6/12 and a difference in best-corrected visual acuity (BCVA) between the two eyes of 0.20 logMAR (2 lines on an acuity chart) in amblyopic eyes ( n , 74) whereas normal eyes had a best-corrected visual acuity of 6/6 and no morbidities ( n , 78). Anisometropic patients ...

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    5. Optical coherence tomography angiography in preclinical neuroimaging

      Optical coherence tomography angiography in preclinical neuroimaging

      Preclinical neuroimaging allows for the assessment of brain anatomy, connectivity, and function in laboratory animals, such as mice and this imaging field has been a rapidly growing aimed at bridging the translation gap between animal and human research. The progress in the animal research could be accelerated by high-resolution in vivo optical imaging technologies. Optical coherence tomography-based angiography (OCTA) estimates the scattering from moving red blood cells, providing the visualization of functional micro-vessel networks within tissue beds in vivo without a need for exogenous contrast agents. Recent advancement of OCTA methods have expanded its application to neuroimaging of small animal ...

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      Mentions: Woo June Choi
    6. An Experimentally Trained Noise Filtration Method of Optical Coherence Tomography Signals

      An Experimentally Trained Noise Filtration Method of Optical Coherence Tomography Signals

      A method for wavelet filtration procedure training for optical coherence tomography (OCT) images using the experimental measurements of test objects that were constructed by means of water solutions of monodisperse nanoparticles and several microscopic inclusions has been described in the present paper. The choice of test-object parameters (concentration of water solution, size of nanoparticles, and shape, dimensions, and mutual position of inclusions) has allowed the modeling of various working conditions of OCT and setting different criteria for estimation of filtration efficiency. In the present work, the optimal filter for the considered example of a test object has been selected among ...

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    7. Intravascular optical coherence tomography image segmentation based on Gaussian mixture model and adaptive fourth-order PDE

      Intravascular optical coherence tomography image segmentation based on Gaussian mixture model and adaptive fourth-order PDE

      The accuracy of the fibrotic plaque segmentation is vital in identifying the coronary artery stenosis. In this paper, we address an automated approach (APDE-GMM) for separating the fibrotic plaque area of intravascular optical coherence tomography (IV-OCT) images. Under this approach, an objective function consisting of a new energy functional with Rayleigh distribution and the negative log-likelihood function of Gaussian mixture model (GMM) is developed. Also, the study presents an adaptive diffusivity function where the gradient threshold can be associated to suppress the effect of speckle noise. The parameter estimation is carried out by the expectation–maximization technology. In addition, this ...

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    8. Laser Imaging: Unraveling Laser Atherectomy Mechanisms of Action with Optical Coherence Tomography

      Laser Imaging: Unraveling Laser Atherectomy Mechanisms of Action with Optical Coherence Tomography

      Purpose of Review The goal is to review the current data regarding excimer laser coronary atherectomy (ELCA) through optical coherence tomography (OCT) imaging. We aim to reveal the mechanisms of action and principles of use for laser, and to analyze the current supportive data. Recent Findings ELCA is an adjuvant procedure to percutaneous coronary intervention, aimed at properly preparing coronary lesions to optimize stenting. It is an effective atherectomy device that requires a short period of training and works on a standard 0.014″ guidewire. Laser modifies coronary vessels by three distinct mechanisms: photoablation, chemoablation and thermoablation. Accordingly, it plays ...

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      Mentions: Hiram G. Bezerra
    9. Clinical diversity in macular corneal dystrophy: an optical coherence tomography study

      Clinical diversity in macular corneal dystrophy: an optical coherence tomography study

      Purpose To characterise the corneal deposits of macular corneal dystrophy and correlate with high-resolution optical coherence tomography (OCT). Methods A total of 23 eyes of 15 patients were evaluated for clinical features on slit lamp biomicroscopy, and high-resolution OCT was performed to correlate the clinical findings. The deposits were characterised based upon their location and level in the corneal layers. Results Mean age was 31.5 (Range 20–67) years. The stromal deposits were restricted to central 8 mm in 9 eyes; in the rest of the 14 eyes, the deposits were seen in both central and peripheral cornea. In ...

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    10. In-stent restenosis caused by calcified nodule 11 years after paclitaxel eluting stent implantation treated with drug-coated balloon following rotational atherectom

      In-stent restenosis caused by calcified nodule 11 years after paclitaxel eluting stent implantation treated with drug-coated balloon following rotational atherectom

      n 82-year-old man with dyslipidemia, diabetes mellitus and chronic kidney disease was admitted to our hospital for heart failure. He was treated with 3 paclitaxel eluting stents in the proximal and mid-right coronary artery (RCA) for silent myocardial ischemia 11 years previously. 2 years after the initial procedure, angioplasty was performed for in-stent restenosis (ISR) in the RCA. He had been stable with optimal medical therapy until the present admission. After admission, CAG upon stabilization of heart failure with medical therapy showed ISR in the mid-RCA (Fig. 1 a). On the first session, neither a 1.0-mm balloon nor imaging ...

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    11. Imaging assessment and accuracy in coronary artery autopsy: comparison of frequency-domain optical coherence tomography with intravascular ultrasound and histology

      Imaging assessment and accuracy in coronary artery autopsy: comparison of frequency-domain optical coherence tomography with intravascular ultrasound and histology

      ptical coherence tomography (OCT) is a coronary artery imaging technique with high resolution. Second-generation frequency-domain OCT (FD-OCT) technology allows safer and faster clinical application compared with first-generation time-domain OCT (TD-OCT). Only limited validation studies compare FD-OCT with other modes of analysis: histology, which is the current gold standard, and intravascular ultrasound (IVUS). This study therefore aims to demonstrate the accuracy of FD-OCT images compared with IVUS and histology. FD-OCT and IVUS images were acquired from 203 segments from 31 coronary arteries obtained at autopsy from 20 cadavers. Of these, 30 randomly-selected pairs were used to create three classifications of plaque ...

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    12. Longitudinal vasculature changes in branch retinal vein occlusion with projection-resolved optical coherence tomography angiography

      Longitudinal vasculature changes in branch retinal vein occlusion with projection-resolved optical coherence tomography angiography

      Purpose To analyze vascular changes in branch retinal vein occlusion (BRVO) using projection-resolved optical coherence tomography angiography (PR-OCTA). Methods We reviewed 30 consecutive eyes of 30 cases with BRVO retrospectively. PR-OCTA was performed during the acute, intermediate, and remission phases when anti-vascular endothelial growth factor drugs suppress cystic changes. The main outcome measures were vessel density (VD) and retinal thickness changes in the superficial capillary plexus (SCP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). Results The VDs did not change longitudinally in the SCP and DCP during the follow-up period. The VD was significantly ( p  = 0.0105) greater ...

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    13. Imaging analysis with optical coherence tomography angiography after primary repair of macula-off rhegmatogenous retinal detachment

      Imaging analysis with optical coherence tomography angiography after primary repair of macula-off rhegmatogenous retinal detachment

      Purpose To evaluate changes in the microcirculation of various retinal layers and choroid following successful repair of macula-off rhegmatogenous retinal detachment (RRD) using optical coherence tomography angiography (OCTA). Methods Twenty-eight patients (28 eyes) who underwent successful repair of macula-off RRD were prospectively investigated. Differences in OCTA characteristics between retinal detachment (RD) and fellow eyes were compared. Quantitative measurements of the retinal capillary and choriocapillary associated with the preoperative and intraoperative factors were analyzed. Results The mean vessel and parafoveal vessel densities were significantly lower in the superficial retinal capillary plexus (SCP) and deep retinal capillary plexus (DCP) in the RD ...

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    14. Application of the Method of Multiple Mutual Synchronization of Parallel Computational Threads in Spectral-Domain Optical Coherent Tomography Systems

      Application of the Method of Multiple Mutual Synchronization of Parallel Computational Threads in Spectral-Domain Optical Coherent Tomography Systems

      A method for multiple mutual synchronization of parallel computational threads, which is used in spectral-domain optical coherence tomography systems, is described. Due to the effective distribution of the computational load in the central processor of the control computer, the method made it possible to perform procedures for calculating tomographic slices of the subsurface tissues of a living organism in real time. The application of this method made it possible to realize the principle of multimodal optical coherence tomography and achieve significant results in a number of medical and biological studies.

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    15. A Simple Algorithm for Hard Exudate Detection in Diabetic Retinopathy Using Spectral-Domain Optical Coherence Tomography

      A Simple Algorithm for Hard Exudate Detection in Diabetic Retinopathy Using Spectral-Domain Optical Coherence Tomography

      Hard exudates are usually seen in the course of diabetic retinopathy. This illness is one of the most common reasons for blind registration in the world. Due to the data presented by World Health Organization (WHO) the number of people who lose sight because of undetected diabetes will be doubled by 2050. The purpose of this paper is to introduce an enhanced algorithm for hard exudates detection in Optical Coherence Tomography images. In these samples, dangerous pathological changes can be observed in the form of yellow-red spots. During the experiments more than 150 images were used to calculate the accuracy ...

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    16. Suitability of intravascular imaging for assessment of cerebrovascular diseases

      Suitability of intravascular imaging for assessment of cerebrovascular diseases

      Purpose Arteriosclerosis of the vascular system is associated with many accompanying diseases. Especially cerebral arteriosclerosis is a main risk factor for ischemic strokes. We want to verify the practicability of intravascular imaging like intravascular ultrasound and optical coherence tomography for the assessment of cerebral vessel walls and plaques. Methods We examined 18 Circuli arteriosi willisii postmortem. The data contained 48 plaques from 48 different vessel parts. The samples underwent intravascular and histological imaging to conduct a quantitative assessment of vessel wall parameters (healthy vessel wall, thinnest vessel wall, plaque thickness and vessel diameter) as well as to qualitatively evaluate the ...

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    17. Effect of drug-coated balloon angioplasty on in-stent restenotic coronary lesions analyzed with optical coherence tomography and serial coronary artery angioscopy

      Effect of drug-coated balloon angioplasty on in-stent restenotic coronary lesions analyzed with optical coherence tomography and serial coronary artery angioscopy

      Drug-coated balloon angioplasty (DCBA) has been recognized for its utility in preventing in-stent re-restenosis (ISR); however, imaging of the neointima immediately after treatment and during follow-up has only been described in a few case reports. This study aimed to determine the efficacy and mechanism of the DCBA using imaging studies both immediately after the DCBA and during the follow-up period. We enrolled 15 consecutive patients who underwent DCBA for in-stent restenosis (ISR). The in-stent neointimal volume was evaluated using optical coherence tomography (OCT), and the in-stent yellow grade was assessed using coronary angioscopy (CAS) immediately after DCBA and during the ...

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    18. New imaging systems in diabetic retinopathy

      New imaging systems in diabetic retinopathy

      Various imaging modalities are of significant utility in the screening, grading, treatment, and follow-up of the different stages of diabetic retinopathy (DR) and diabetic macular edema. Color stereographic photography, fluorescein angiography, and optical coherence tomography (OCT) have been the gold standard for DR imaging for years. Besides these tools, newer technologies are gaining validation and popularity, such as fundus autofluorescence and OCT angiography. Furthermore, widefield retinography and ultra-widefield retinography have been introduced for a more comprehensive evaluation of the medium-far and very-far retinal peripheries, which is crucial for the assessment of the diverse manifestations of the disease. The aim of ...

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    19. Optical Coherence Tomography as an Adjunct During Carotid Artery Stenting for Carotid Atherosclerotic Disease

      Optical Coherence Tomography as an Adjunct During Carotid Artery Stenting for Carotid Atherosclerotic Disease

      Purpose Carotid artery stenting (CAS) has been proven to decrease the risk of stroke in symptomatic patients with moderate/high-grade carotid stenosis; however, there is an increased periprocedural risk of stroke with CAS compared to carotid endarterectomy. The goal of this article is to report the utilization of endovascular optical coherence tomography (OCT) during CAS to aid in the identification of stent malapposition, plaque prolapse, and adjacent residual thrombus that could cause periprocedural stroke. Methods Approval was obtained for endovascular OCT imaging in patients undergoing CAS. Images were obtained before and after stenting. Images were acquired with proximal balloon occlusion ...

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    20. Optical coherence tomography angiography (OCTA) as a new diagnostic tool in uveitis

      Optical coherence tomography angiography (OCTA) as a new diagnostic tool in uveitis

      Background The broad spectrum of uveitis disorders requires a multimodal imaging approach in the daily practice of an ophthalmologist. As inflammatory conditions, they have in common an alteration in leukocyte migration. In this context, optical coherence tomography angiography (OCTA) might be of great value for diagnosing or following up patients with these disorders. To date, OCTA has rather been used as an additional tool besides the well-established diagnostic imaging tools, but its complementary diagnostic features become increasingly relevant, to follow disease activity and treatment response and for the understanding of pathomechanisms of various uveitis types. This review summarizes the possible ...

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    21. Dynamic intraoperative optical coherence tomography for inverted internal limiting membrane flap technique in large macular hole surgery

      Dynamic intraoperative optical coherence tomography for inverted internal limiting membrane flap technique in large macular hole surgery

      Background/objectives To assess the efficacy of dynamic intraoperative spectral-domain optical coherence tomography (iSD-OCT) imaging for inverted internal limiting membrane (ILM) flap technique (IILMFT) in large macular hole (MH) surgery. Subjects/methods Prospective, non-randomized, observational study was conducted on 8 eyes of 7 patients with large, chronic and recurrent MHs, which were treated by pars plana vitrectomy (PPV) with IILMFT. All patients underwent standard pre- and postoperative examination. The iSD-OCT imaging was performed using microscope integrated systems before, during, and after ILM peeling. The iSD-OCT data were post-processed using graphic software and reviewed for tissue behavior and instruments position. Results ...

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