All Articles from Hiram G. Bezerra -Optical Coherence Tomography News

Articles from Hiram G. Bezerra

1-24 of 88 1 2 3 4 »
1. Fractional Flow Reserve (FFR) Estimation from OCT-Based CFD Simulations: Role of Side Branches
  
  Explore MDPI Open Access Journals Platform Oct 31 2022 Cardiology
  
  The computational fluid dynamic method has been widely used to quantify the hemodynamic alterations in a diseased artery and investigate surgery outcomes. The artery model reconstructed based on optical coherence tomography (OCT) images generally does not include the side branches. However, the side branches may significantly affect the hemodynamic assessment in a clinical setting, i.e., the fractional flow reserve (FFR), defined as the ratio of mean distal coronary pressure to mean aortic pressure. In this work, the effect of the side branches on FFR estimation was inspected with both idealized and optical coherence tomography (OCT)-reconstructed coronary artery models ...
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  Mentions: Case Western Reserve University University of South Florida
2. Automated segmentation of microvessels in intravascular OCT images using deep learning
  
  Explore arxiv.org Oct 21 2022 Cardiology
  
  To analyze this characteristic of vulnerability, we developed an automated deep learning method for detecting mi- crovessels in intravascular optical coherence tomography (IVOCT) images. A total of 8,403 IVOCT image frames from 85 lesions and 37 normal segments were analyzed. Manual annotation was done using a dedicated software (OCTOPUS) previously developed by our group. Data augmentation in the polar ( r , θ ) domain was applied to raw IVOCT images to ensure that microvessels appear at all possible angles. Pre-processing methods included guide- wire/shadow detection, lumen segmentation, pixel shifting, and noise reduction. DeepLab v3+ was used to segment microvessel candidates. A ...
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  Mentions: Case Western Reserve University
3. Assessment of post-dilatation strategies for optimal stent expansion in calcified coronary lesions: Ex vivo analysis with optical coherence tomography
  
  Explore ScienceDirect May 23 2022 Cardiology
  
  Introduction: Interventional cardiologists make adjustments in the presence of coronary calcifications known to limit stent expansion, but proper balloon sizing, plaque-modification approaches, and high-pressure regimens are not well established. Intravascular optical coherence tomography (IVOCT) provides high-resolution images of coronary tissues, including detailed imaging of calcifications, and accurate measurements of stent deployment, providing a means for detailed study of stent deployment. Objective: Evaluate stent expansion in an ex vivo model of calcified coronary arteries as a function of balloon size and high-pressure, post-dilatation strategies. Methods: We conducted experiments on cadaver hearts with calcified coronary lesions. We assessed stent expansion as a ...
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  Mentions: Case Western Reserve University
4. Learning With Fewer Images via Image Clustering: Application to Intravascular OCT Image Segmentation
  
  Explore IEEE Xplore Apr 9 2021 Cardiology
  
  Deep learning based methods are routinely used to segment various structures of interest in varied medical imaging modalities. Acquiring annotations for a large number of images requires a skilled analyst, and the process is both time consuming and challenging. Our approach to reduce effort is to reduce the number of images needing detailed annotation. For intravascular optical coherence tomography (IVOCT) image pullbacks, we tested 10% to 100% of training images derived from two schemes: equally-spaced image subsampling and deep-learning- based image clustering. The first strategy involves selecting images at equally spaced intervals from the volume, accounting for the high spatial ...
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  Mentions: Case Western Reserve University
5. A feasibility study of the DyeVert™ plus contrast reduction system to reduce contrast media volumes in percutaneous coronary procedures using optical coherence tomography
  
  Explore ScienceDirect Oct 15 2020 Cardiology
  
  bjective To evaluate the feasibility of using the DyeVert™ Plus EZ Contrast Reduction System in optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) procedures and to assess OCT image quality. Background OCT is employed as a powerful intravascular imaging modality; however, it requires blood displacement via contrast injection during image acquisition, thereby posing risk of nephrotoxicity. The DyeVert System is designed to reduce and facilitate monitoring of contrast media volume (CMV) delivered, without diminishing image quality. Methods We conducted a prospective clinical feasibility study to determine whether the DyeVert System is non-inferior to manual contrast injection in reducing CMV ...
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6. OPtical Coherence Tomography Guided Coronary Stent IMplantation Compared to Angiography: A Multicenter Randomized TriaL in PCI
  
  Explore eurointervention.pcronline.com Sep 5 2020 Cardiology
  
  AIMS: Randomized trials have demonstrated improvement in clinical outcomes with intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) compared with angiography-guided PCI. The ILUMIEN III trial demonstrated non-inferiority of an optical coherence tomography (OCT)- versus IVUS-guided PCI strategy in achieving similar post-PCI lumen dimensions. ILUMIEN IV is a large-scale, multicenter, randomized trial designed to demonstrate the superiority of OCT- versus angiography-guided stent implantation in patients with high-risk clinical characteristics (diabetes) and/or complex angiographic lesions in achieving larger post-PCI lumen dimensions and improving clinical outcomes. METHODS AND RESULTS: ILUMIEN IV is a prospective, single-blind clinical investigation that will randomize between ...
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  Mentions: Columbia University Mount Sinai School of Medicine Cardiovascular Research Foundation
7. An assessment of the quality of optical coherence tomography image acquisition
  
  Explore Home - Springer Feb 22 2020 Cardiology
  
  Optical coherence tomography (OCT) provides excellent image resolution, however OCT optimal acquisition is essential but could be challenging owing to several factors. We sought to assess the quality of OCT pullbacks and identify the causes of suboptimal image acquisition. We evaluated 784 (404 pre-PCI; 380 post-PCI) coronary pullbacks from an anonymized OCT database from our Cardiovascular Imaging Core Laboratory. Imaging of the region-of-interest (ROI—lesion or stented segment plus references) was incomplete in 16.1% pullbacks, caused by pullback starting too proximal (63.7%), inappropriate pullback length (17.1%) and pullback starting too distal (11.4%). The quality of image ...
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  Mentions: UT Southwestern Medical Center
8. Fully automated plaque characterization in intravascular OCT images using hybrid convolutional and lumen morphology features
  
  Explore Nature Publishing Group Feb 16 2020 Cardiology
  
  For intravascular OCT (IVOCT) images, we developed an automated atherosclerotic plaque characterization method that used a hybrid learning approach, which combined deep-learning convolutional and hand-crafted, lumen morphological features. Processing was done on innate A-line units with labels fibrolipidic (fibrous tissue followed by lipidous tissue), fibrocalcific (fibrous tissue followed by calcification), or other. We trained/tested on an expansive data set (6,556 images), and performed an active learning, relabeling step to improve noisy ground truth labels. Conditional random field was an important post-processing step to reduce classification errors. Sensitivities/specificities were 84.8%/97.8% and 91.4%/95.7 ...
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  Mentions: Case Western Reserve University Cleveland Clinic
9. Application and Evaluation of Highly Automated Software for Comprehensive Stent Analysis in Intravascular Optical Coherence Tomography
  
  Explore Nature Publishing Group Feb 12 2020 Cardiology
  
  Intravascular optical coherence tomography (IVOCT) is used to assess stent tissue coverage and malapposition in stent evaluation trials. We developed the OCT Image Visualization and Analysis Toolkit for Stent (OCTivat-Stent), for highly automated analysis of IVOCT pullbacks. Algorithms automatically detected the guidewire, lumen boundary, and stent struts; determined the presence of tissue coverage for each strut; and estimated the stent contour for comparison of stent and lumen area. Strut-level tissue thickness, tissue coverage area, and malapposition area were automatically quantified. The software was used to analyze 292 stent pullbacks. The concordance-correlation-coefficients of automatically measured stent and lumen areas and independent ...
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  Mentions: Massachusetts Institute of Technology Case Western Reserve University
10. Optical Coherence Tomography-Based Modeling of Stent Deployment in Heavily Calcified Coronary Lesion
  
  Explore ASME Digital Collection Jan 28 2020 Cardiology
  
  In this work, a heavily calcified coronary artery model was reconstructed from optical coherence tomography (OCT) images to investigate the impact of calcification characteristics on stenting outcomes. The calcification was quantified at various cross sections in terms of angle, maximum thickness, and area. The stent deployment procedure, including the crimping, expansion, and recoil, was implemented. The influence of calcification characteristics on stent expansion, malapposition, and lesion mechanics was characterized. Results have shown that the minimal lumen area following stenting occurred at the cross section with the greatest calcification angle. The calcification angle constricted the stretchability of the lesion and thus ...
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  Mentions: Case Western Reserve University
11. Automated plaque characterization using deep learning on coronary intravascular optical coherence tomographic images
  
  Explore OSA | OSA Publishing Dec 1 2019 Cardiology
  
  Accurate identification of coronary plaque is very important for cardiologists when treating patients with advanced atherosclerosis. We developed fully-automated semantic segmentation of plaque in intravascular OCT images. We trained/tested a deep learning model on a folded, large, manually annotated clinical dataset. The sensitivities/specificities were 87.4%/89.5% and 85.1%/94.2% for pixel-wise classification of lipidous and calcified plaque, respectively. Automated clinical lesion metrics, potentially useful for treatment planning and research, compared favorably (<4%) with those derived from ground-truth labels. When we converted the results to A-line classification, they were significantly better (p < 0.05) than ...
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  Mentions: Case Western Reserve University
12. Automated A-line coronary plaque classification of intravascular optical coherence tomography images using handcrafted features and large datasets
  
  Explore SPIE Digital Library Oct 9 2019 Cardiology
  
  We developed machine learning methods to identify fibrolipidic and fibrocalcific A-lines in intravascular optical coherence tomography (IVOCT) images using a comprehensive set of handcrafted features. We incorporated features developed in previous studies (e.g., optical attenuation and A-line peaks). In addition, we included vascular lumen morphology and three-dimensional (3-D) digital edge and texture features. Classification methods were developed using expansive datasets (∼7000 images), consisting of both clinical in-vivo images and an ex-vivo dataset, which was validated using 3-D cryo-imaging/histology. Conditional random field was used to perform 3-D classification noise cleaning of classification results. We tested various multiclass approaches, classifiers ...
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  Mentions: Case Western Reserve University
13. Diagnostic accuracy of intracoronary optical coherence tomography-derived fractional flow reserve for assessment of coronary stenosis severity
  
  Explore eurointervention.pcronline.com Jun 6 2019 Cardiology
  
  $Diagnostic accuracy of intracoronary optical coherence tomography-derived fractional flow reserve for assessment of coronary stenosis severity$
  ims: A novel method for computation of fractional flow reserve (FFR) from optical coherence tomography (OCT) was developed recently. This study aimed to evaluate the diagnostic accuracy of a new OCT-based FFR (OFR) computational approach, using wire-based FFR as the reference standard. Methods and results: Patients who underwent both OCT and FFR prior to intervention were analysed. The lumen of the interrogated vessel and the ostia of the side branches were automatically delineated and used to compute OFR. Bifurcation fractal laws were applied to correct the change in reference lumen size due to the step-down phenomenon. OFR was compared with ...
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  Mentions: Case Western Reserve University Capital Medical University Shanghai Jiao Tong University
14. Automated analysis of intravascular OCT image volumes
  
  Explore uspto.gov Mar 12 2019 Cardiology , Patents
  
  This disclosure provides systems and methods to automatically classify stent struts as covered or uncovered and to measure the thickness of tissue coverage. As one example, the method includes storing three-dimensional image data acquired intravascularly via an optical coherence tomography (OCT) apparatus and detecting struts based on analysis of the image data. Image data corresponding to each of the detected struts is further analyzed automatically to compute an indication of tissue coverage for the stent.
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  Mentions: Case Western Reserve University
15. Analysis of optical tomography (OCT) images
  
  Explore uspto.gov Feb 26 2019 Cardiology , Patents
  
  A method includes storing three-dimensional image data acquired intravascularly via an optical coherence tomography (OCT) apparatus. The image data is analyzed to compute a probability estimate of stent presence at support positions appearing in an A-line. Stent strut locations are located in three-dimensional space based on the computed probability estimate of stent presence.
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  Mentions: Case Western Reserve University
16. Intravascular Optical Coherence Tomography for Neurointerventional Surgery
  
  Explore Home | AHA/ASA Journals Dec 3 2018 Cardiology , Neurology
  
  Optical coherence tomography (OCT) is a high-resolution imaging modality that uses backscattered light to produce cross-section images of biological tissue with micrometer resolution...
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  Mentions: Case Western Reserve University Cleveland Clinic SUNY at Stony Brook
17. New Volumetric Analysis Method for Stent Expansion and its Correlation With Final Fractional Flow Reserve and Clinical Outcome An ILUMIEN I Substudy
  
  Explore interventions.onlinejacc.org Aug 12 2018 Cardiology
  
  Download figure Open in new tab Download powerpoint Abstract Objectives This study sought to compare conventional methodology (CM) with a newly described optical coherence tomography (OCT)-derived volumetric stent expansion analysis in terms of fractional flow reserve (FFR)-derived physiology and device-oriented composite endpoints (DoCE). Background The analysis of coronary stent expansion with intracoronary imaging has used CM that relies on the analysis of selected single cross-sections for several decades. The introduction of OCT with its ability to perform semiautomated volumetric analysis opens opportunities to redefine optimal stent expansion. Methods A total of 291 lesions treated with post-stent OCT and ...
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  Mentions: Case Western Reserve University Cardiovascular Research Foundation Wakayama Medical University
18. Optimizing Percutaneous Coronary Intervention in Calcified Lesions Insights From Optical Coherence Tomography of Atherectomy
  
  Explore Circulation May 11 2018 Cardiology
  
  Optimal coronary stent implantation is among the few successful strategies in preventing stent failures, notably in-stent restenosis and stent thrombosis. 1 Understanding the intravascular milieu is a prerequisite for optimization of percutaneous coronary intervention (PCI). Calcified lesions limit stent expansion, the most robust predictor of target lesion revascularization, and are thus associated with worst outcomes. 2 Coronary angiography is a poor discriminator of calcium distribution and thickness. Reliance on angiography to guide PCI and define procedural success in severe coronary calcification is associated with poor outcomes. 3 Both intravascular ultrasound and optical coherence tomography (OCT) enable detailed evaluation of cross-sectional ...
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  Mentions: Case Western Reserve University Brown University
19. Association of skin autofluorescence with plaque vulnerability evaluated by optical coherence tomography in patients with cardiovascular disease
  
  Explore atherosclerosis-journal.com Mar 2 2018 Cardiology , Dermatology
  
  Background and aims Accumulation of advanced glycation end products (AGEs) can be measured non-invasively by skin autofluorescence (SAF) whose values are elevated in patients with cardiovascular disease (CVD). Optical coherence tomography (OCT) is an intravascular imaging modality that could allow visualization of plaque composition. We aim to examine the relationship between SAF and plaque composition evaluated by frequency-domain OCT in patients with CVD. Methods We prospectively enrolled 108 patients with CVD who underwent OCT images during percutaneous coronary intervention (PCI). We divided the population into two groups: high SAF group (greater than or equal to 2.6) and low SAF ...
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  Mentions: Case Western Reserve University Sun Yat-Sen University
20. Optical Coherence Tomography Assessment Prevented Unnecessary Intervention in an “Ambiguous” Angiographic Image
  
  Explore ScienceDirect Nov 15 2017 Cardiology
  
  Images in intervention.
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21. OCT Made Easy (Textbook)
  
  Explore CRC Press Online Oct 20 2017 Cardiology , Textbooks
  
  This book, written by premier authors in the field of OCT intravascular imaging, covers the best practices for using OCT to provide high resolution cross-sectional viewing for atherosclerotic plaque assessment, stent strut coverage and apposition, assessment in stent restenosis evaluation, and PCI guide and optimization. Fully illustrated thorughout in a handy, cath-lab side handbook supplemented by online movie clips, OCT Made Easy includes case studies, angiography, CT correlations, and simple techniques for getting the best image.
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  Mentions: Case Western Reserve University
22. The REMEDEE-OCT Study : An Evaluation of the Bioengineered COMBO Dual-Therapy CD34 Antibody–Covered Sirolimus-Eluting Coronary Stent Compared With a Cobalt-Chromium Everolimus-Eluting Stent in Patients With Acute Coronary Syndromes: Insights From Optical
  
  Explore ScienceDirect Mar 11 2017 Cardiology
  
  Objectives The aim of the present study was to evaluate vascular healing of the bioengineered COMBO Dual Therapy Stent compared with a cobalt-chromium (CoCr) everolimus-eluting stent (EES) as assessed by optical coherence tomography in patients with acute coronary syndromes. Background CD34+ cells promote endothelial repair after vascular injury. The bioengineered COMBO Dual Therapy Stent combines CD34+ cell–capturing technology with abluminal sirolimus release, but more data from clinical studies evaluating the vascular response are needed. Methods In a prospective randomized multicenter clinical trial, 60 patients with acute coronary syndromes were randomized 1:1 to COMBO or CoCr EES implantation. The ...
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  Mentions: Case Western Reserve University Cardiovascular Research Foundation Academic Medical Center at the University of Amsterdam
23. Fate of Nonculprit Plaques in Patients With STEMI Undergoing Primary PCI Followed by Statin Therapy : A Serial Optical Coherence Tomography Analysis From the OCTAVIA Study
  
  Explore ScienceDirect Dec 27 2016 Cardiology
  
  Letter to the editor.
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24. Difference in Vascular Response between Sirolimus-eluting- and Everolimus-eluting Stents in Ostial Left Circumflex Artery after Unprotected Left Main as Observed by
  
  Explore Elsevier Health Dec 23 2016 Cardiology
  
  Background Kissing-balloon technique (KBT) is commonly performed during percutaneous coronary intervention of distal unprotected left main coronary artery (ULM) aiming at obtaining optimal opening of the side branch (left circumflex artery; LCX) ostium. Nonetheless, detailed evaluation of vascular response to stents in LCX ostium is lacking. We therefore evaluated the vascular response to different drug-eluting stents (DES) in ostial LCX after ULM by means of optical coherence tomography (OCT). Methods We prospectively enrolled 38 consecutive patients with ULM disease, whom were treated with single-stent procedure using DES, crossover the ULM-left anterior descending artery (LAD) following by KBT. Twelve patients were ...
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  Mentions: Case Western Reserve University
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