1. Articles from Hiram G. Bezerra

    49-72 of 78 « 1 2 3 4 »
    1. Frequency-domain optical coherence tomography assessment of very late vascular response after carotid stent implantation

      Frequency-domain optical coherence tomography assessment of very late vascular response after carotid stent implantation

      Intravascular optical coherence tomography is a high-resolution invasive imaging modality that allows the evaluation of vascular responses after stent implantation in a micron-scale level. We describe for the first time two patients with very late vascular response after carotid artery stenting that exhibit two different patterns of low-signal intensity (LSI), "ill-appearing" neointima: the first patient shows layered LSI neointima leading to stent restenosis, coupled with the presence of intraluminal thrombus, whereas the second patient demonstrates another pattern of non-restenotic LSI stent strut coverage, suggestive of lipid laden neointima (ie, "neoatherosclerosis"), recently associated with stent failure in coronary arteries.

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    2. Feature Of The Week 1/20/13: CWRU Demonstrates Automatic Stent Detection in Intravascular OCT Images Using Bagged Decision Trees

      Feature Of The Week 1/20/13: CWRU Demonstrates Automatic Stent Detection in Intravascular OCT Images Using Bagged Decision Trees

      Cardiovascular disease is the leading cause of death worldwide. Stent implantation by means of percutaneous coronary intervention is the most common coronary revascularization procedure. Intravascular Optical Coherence Tomography (iOCT) is the only imaging modality with the resolution and contrast necessary to enable accurate measurements of luminal architecture and neointima stent coverage. Manual analysis of intravascular OCT pullbacks is time consuming, limiting the size and number of studies that can be performed. We developed a highly automated method for detecting stent struts and measuring tissue coverage. Candidate struts were first identified using image processing techniques. We trained a bagged decision trees ...

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    3. Serial Evaluation of Vascular Response After Implantation of a New Sirolimus-Eluting Stent with Bioabsorbable Polymer (MISTENT): An Optical Coherence Tomography and Histopathological Study

      Serial Evaluation of Vascular Response After Implantation of a New Sirolimus-Eluting Stent with Bioabsorbable Polymer (MISTENT): An Optical Coherence Tomography and Histopathological Study

      Abstract: Background. Novel vascular scaffolds aim at equipoise between safety and efficacy. Intravascular optical coherence tomography (OCT) allows in-vivo serial assessment of stent-vessel interactions with high resolution and frequent sampling and may complement histology assessment. We investigated the vascular response to a novel absorbable coating sirolimus-eluting stent (AC-SES) by means of serial OCT and histology evaluation in a porcine model. Methods. One AC-SES and one bare-metal stent (BMS) were implanted in separate coronary arteries of three Yucatan mini-swine. Serial OCT was performed post procedure and at 3-, 28-, 90-, and 180-day follow-up. Normalized optical density (NOD) was used for the ...

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    4. Automatic stent detection in intravascular OCT images using bagged decision trees

      Automatic stent detection in intravascular OCT images using bagged decision trees

      Intravascular optical coherence tomography (iOCT) is being used to assess viability of new coronary artery stent designs. We developed a highly automated method for detecting stent struts and measuring tissue coverage. We trained a bagged decision trees classifier to classify candidate struts using features extracted from the images. With 12 best features identified by forward selection, recall (precision) were 90%–94% (85%–90%). Including struts deemed insufficiently bright for manual analysis, precision improved to 94%. Strut detection statistics approached variability of manual analysis. Differences between manual and automatic area measurements were 0.12 ± 0.20 mm 2 and 0.11 ...

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    5. Unrestricted utilization of frequency domain optical coherence tomography in coronary interventions

      Unrestricted utilization of frequency domain optical coherence tomography in coronary interventions

      Frequency domain optical coherence tomography (FD-OCT) has shown promise to evaluate coronary devices in clinical trials, however, little is known about its application in clinical practice. This prospective, single center initiative planned for 100 % FD-OCT utilization in all patients undergoing coronary interventions during a 60-day period. Operators pre-specified the planned intervention based on angiography alone. FD-OCT success was defined as acquisition of good quality images enabling adequate quantification of vessel dimensions and lesion/percutaneous coronary intervention (PCI) assessment. Impact on management occurred when angiography-based planning was altered based on FD-OCT data. There were 297 FD-OCT acquisitions performed in 155 vessels ...

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    6. Novel use of optical coherence tomograph

      Novel use of optical coherence tomograph
      Currently in use by interventional cardiology for the intravascular evaluation of coronary arteries, optical coherence tomography (OCT) has proven to be effective in the evaluation of atherosclerotic disease and further therapeutic management. We report a novel use of OCT technology in the case of a 46-year-old man with sudden onset blurred vision and greater than 70% stenosis of his left vertebral artery. To date, no detailed descriptions or case reports have previously been reported regarding the use of neuroendovascular OCT in diseased arteries.
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    7. Expert review document part 2: methodology, terminology and clinical applications of optical coherence tomography for the assessment of interventional procedures

      Expert review document part 2: methodology, terminology and clinical applications of optical coherence tomography for the assessment of interventional procedures

      Introduction This document is complementary to an Expert Review Document on Optical Coherence Tomography (OCT) for the study of coronary arteries and atherosclerosis.1 The goal of this companion manuscript is to provide a practical guide framework for the appropriate use and reporting of the novel frequency domain (FD) OCT imaging to guide interventional procedures, with a particular interest on the comparison with intravascular ultrasound (IVUS).1–4 Technique for optical coherence tomography imaging In the OCT Expert Review Document on Atherosclerosis, a comprehensive description of the physical principles for OCT imaging and time domain (TD) catheters (St Jude Medical ...

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    8. Volumetric quantification of fibrous caps using intravascular optical coherence tomography

      Volumetric quantification of fibrous caps using intravascular optical coherence tomography

      The rupture of thin-cap fibroatheroma accounts for most acute coronary events. Optical Coherence Tomography (OCT) allows quantification of fibrous cap (FC) thickness in vivo. Conventional manual analysis, by visually determining the thinnest part of the FC is subject to inter-observer variability and does not capture the 3-D morphology of the FC. We propose and validate a computer-aided method that allows volumetric analysis of FC. The radial FC boundary is semi-automatically segmented using a dynamic programming algorithm. The thickness at every point of the FC boundary, along with 3-D morphology of the FC, can be quantified. The method was validated against ...

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    9. Feasibility and Safety of the Second-Generation, Frequency Domain Optical Coherence Tomography (FD-OCT): A Multicenter Study

      Feasibility and Safety of the Second-Generation, Frequency Domain Optical Coherence Tomography (FD-OCT): A Multicenter Study

      Abstract: Objectives. This study sought to assess the effectiveness and safety of the second-generation frequency-domain optical coherence tomography (FD-OCT) system. Background. The second-generation FD-OCT was recently developed, with simplified imaging technique and faster acquisition time compared to the first-generation time-domain OCT. However, the safety and effectiveness of the FD-OCT has not been evaluated, and this study was conceived as a pre-approval study for Food and Drug Administration clearance for clinical use in the United States. Methods. A total of 50 patients were enrolled from 3 institutions. Following stent implantation, the FD-OCT was performed with contrast injection through the guiding catheter ...

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    10. Impact of different stent alloys on human vascular response to everolimus-eluting stent. An optical coherence tomography study. The OCTEVEREST

      Impact of different stent alloys on human vascular response to everolimus-eluting stent. An optical coherence tomography study. The OCTEVEREST

      Background: New generation drug-eluting stents (DES) incorporate thinner struts and novel alloys to improve clinical performance. Nevertheless, the impact of novel stent materials and designs on human vascular response to DES remains elusive. We sought to evaluate the in-vivo coronary artery response to platinum-chromium (PtCr) versus cobalt-chromium (CoCr) stents featuring the same durable polymer and antiproliferative drug by optical coherence tomography (OCT). Methods and Results: A total of 42 patients with de novo lesions in native coronary vessels was treated with PtCr-everolimus eluting stent (EES) (n=21) or CoCr-EES (n=21). Angiography, intravascular ultrasound, and OCT were performed at the ...

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    11. Consensus Standards for Acquisition, Measurement, and Reporting of Intravascular Optical Coherence Tomography Studies: A Report From the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation

      Consensus Standards for Acquisition, Measurement, and Reporting of Intravascular Optical Coherence Tomography Studies: A Report From the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation

      Objectives: The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the diagnosis and treatment of patients with atherosclerosis, including coronary artery disease.Background: Intravascular optical coherence tomography (IVOCT) is a catheter-based modality that acquires images at a resolution of 10 μm, enabling visualization of blood vessel wall microstructure in vivo at an unprecedented level of detail. IVOCT devices are now commercially available worldwide, there is an active user base, and ...

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    12. Intravascular Optical Coherence Tomography Detection of Atherosclerosis and Inflammation in Murine Aorta

      Intravascular Optical Coherence Tomography Detection of Atherosclerosis and Inflammation in Murine Aorta

      Objective—The goal of this study was to evaluate the feasibility of imaging the aorta of apolipoprotein E–deficient (ApoE−/−) mice for the detection of atherosclerosis and macrophages using optical coherence tomography (OCT) compared with histology. Methods and Results—Atherosclerosis was induced by high-fat diet in 7-week-old ApoE−/− mice for 10 (n=7) and 22 (n=7) weeks. Nine-week-old ApoE−/− mice (n=7) fed a standard chow diet were used as controls. OCT images of a 10-mm descending aorta in situ were performed in 4 mice for each, and plaque and macrophages were determined at 0.5-mm intervals. Automated detection ...

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    13. Serial Assessment of Coronary Artery Response to Paclitaxel-Eluting Stents Using Optical Coherence Tomography

      Serial Assessment of Coronary Artery Response to Paclitaxel-Eluting Stents Using Optical Coherence Tomography

      Background—The paucity of longitudinal, serial high-resolution imaging studies has limited our understanding of in vivo arterial response to drug-eluting stents. We sought to investigate the human coronary response to paclitaxel-eluting stent implantation, using serial optical coherence tomography assessments. Methods and Results—Thirty patients with at least 2 significant coronary lesions in different vessels were treated with a paclitaxel-eluting stent. The most severe stenosis (lesion A) was treated at the initial procedure, and the second target vessel (lesion B) was stented 3 months later. Optical coherence tomography was performed at baseline, 3-, and 9-month follow-up for lesions A and baseline ...

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    14. Congratulations to Zhao Wang from CWRU a Winner of a 2012 Student Travel Grant Award

      Congratulations to Zhao Wang from CWRU a Winner of a 2012 Student Travel Grant Award
      Zhao Wang from Case Western Reserve University is one of four winners of the OCT News 2012 student travel grant awards (see prior announcement Here). Below is a summary of his work.   Coronary artery disease is the leading cause of death worldwide. The rupture of thin-cap fibroatheroma (TCFA) accounts for most acute coronary events. Optical Coherence Tomography (OCT) is able to quantify the fibrous cap (FC) thickness in vivo. Conventional analysis measuring the thinnest part of the FC is subject to inter-observer variability and does not capture the 3-D morphology of the FC. The aim of this study is to ...
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    15. Optical coherence tomography assessment of calcified plaque modification after rotational atherectomy

      Optical coherence tomography assessment of calcified plaque modification after rotational atherectomy

      Rotational atherectomy (RA) facilitates stent delivery in highly calcified coronary plaques (CCP). However, lesion ablation by RA in angulated segments may be affected by guidewire bias, leading to a non-uniform plaque modification. Intravascular optical coherence tomography (iOCT) is the highest resolution (∼10 μm axial) intravascular imaging modality available for clinical use; furthermore, near infrared light easily penetrates calcium, with significantly fewer artifacts, including no “blooming effect” as seen by intravascular ultrasound. Therefore, it may pose as a unique tool for serial calcium quantification, as related in this article with pre- and post-RA assessment, allowing accurate characterization of plaque modification, as ...

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    16. Three-dimensional imaging of fibrous cap by frequency-domain optical coherence tomography

      Three-dimensional imaging of fibrous cap by frequency-domain optical coherence tomography

      Histopathological data correlated the presence of thin-cap fibroatheroma (TCFA) with adverse cardiovascular events. Intravascular optical coherence tomography (iOCT) is currently the only imaging modality with sufficiently high axial resolution (∼15µm) that allows direct fibrous-cap (FC) assessment in vivo. iOCT quantification of TCFA has been validated, but the assessment of a single cross-sectional image does not depict the complexity of the atherosclerotic plaque. We present two cases that illustrate the importance of three-dimensional volumetric quantification of the FC capitalizing on the properties of frequency-domain iOCT.

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    17. The impact of an eccentric intravascular ImageWire during coronary optical coherence tomography imaging

      The impact of an eccentric intravascular ImageWire during coronary optical coherence tomography imaging
      Optical Coherence Tomography (OCT) provides high-resolution imaging which enables characterisation of atherosclerosis and vascular response to injury, but to ensure optimal analysis, one must realise potential sources of image distortion. We designed a series of analysesl, using coronary stents as a model, to investigate the influence of wire position on OCT-derived vascular images.
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    18. Utilization of frequency domain optical coherence tomography and fractional flow reserve to assess intermediate coronary artery stenoses: conciliating anatomic and physiologic information

      Utilization of frequency domain optical coherence tomography and fractional flow reserve to assess intermediate coronary artery stenoses: conciliating anatomic and physiologic information

      Fractional flow reserve (FFR) and intravascular imaging respectively provide hemodynamic and anatomical assessments of angiographic intermediate stenoses. Frequency domain optical coherence tomography (FD-OCT) is a promising high-resolution imaging modality, but its clinical use in determining severity of coronary disease has yet to be determined. There, we set out to determine the role of FD-OCT to complement FFR in the evaluation of intermediate coronary artery stenoses. FD-OCT was planned in 176 consecutive interventional procedures at our institution to delineate the proper use of FD-OCT in clinical practice. The decision to use other invasive assessments was at the discretion of the operator ...

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    19. Plaque and thrombus evaluation by optical coherence tomography

      Plaque and thrombus evaluation by optical coherence tomography
      Intravascular Optical Coherence Tomography has been explored as an imaging tool for vessel wall and thrombus characterization. OCT enables a high resolution arterial wall imaging, and light properties allow tissue characterization. It has been proved one of the most valuable imaging modalities for the evaluation of vulnerable plaque and thrombus. OCT has a unique capacity in volumetric quantification of calcium, and unlike ultrasound, light can easily penetrate calcified plaques. Finally, this review paper will address aspects of the validation method of plaque characterization and potential pitfalls and put in perspective new approaches that may help the evolution of the field.
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    20. Strut Coverage and Late Malapposition With Paclitaxel-Eluting Stents Compared With Bare Metal Stents in Acute Myocardial Infarction: OCT Substudy of the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI)

      Strut Coverage and Late Malapposition With Paclitaxel-Eluting Stents Compared With Bare Metal Stents in Acute Myocardial Infarction: OCT Substudy of the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI)
      Background— The safety of drug-eluting stents in ST-segment elevation myocardial infarction (STEMI) continues to be debated. Pathological studies have demonstrated an association between uncovered struts and subsequent stent thrombosis. Optical coherence tomography can detect stent strut coverage in vivo on a micron-scale level. We therefore used optical coherence tomography to examine strut coverage in patients with STEMI treated with paclitaxel-eluting stents (PES) and bare metal stents (BMS). Methods and Results— In the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, patients with STEMI were randomized 3:1 to PES or BMS implantation. In a formal substudy ...
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    21. Semiautomatic segmentation and quantification of calcified plaques in intracoronary optical coherence tomography images

      Semiautomatic segmentation and quantification of calcified plaques in intracoronary optical coherence tomography images
      Coronary calcified plaque (CP) is both an important marker of atherosclerosis and major determinant of the success of coronary stenting. Intracoronary optical coherence tomography (OCT) with high spatial resolution can provide detailed volumetric characterization of CP. We present a semiautomatic method for segmentation and quantification of CP in OCT images. Following segmentation of the lumen, guide wire, and arterial wall, the CP was localized by edge detection and traced using a combined intensity and gradient-based level-set model. From the segmentation regions, quantification of the depth, area, angle fill fraction, and thickness of the CP was demonstrated. Validation by comparing the ...
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    22. Angiographic, IVUS and OCT evaluation of the long-term impact of coronary disease severity at the site of overlapping drug-eluting and bare metal stents: a substudy of the ODESSA trial

      Angiographic, IVUS and OCT evaluation of the long-term impact of coronary disease severity at the site of overlapping drug-eluting and bare metal stents: a substudy of the ODESSA trial
      Background A potentially adverse vascular response to overlapping drug eluting stents (DES) has been suggested in current research. Objective To evaluate the impact of baseline disease severity at the site of stent overlap. Methods and results This is a substudy of ODESSA, a prospective, randomised controlled trial designed to evaluate healing of overlapping stents. 71/77 patients with a total of 86 overlapping stents were studied: 25 sirolimus, 24 paclitaxel, 26 zotarolimus-eluting stents; and 11 bare metal stents (BMS). Patients were categorised into high-grade stenosis (HGS, ≥70% diameter stenosis) and low-grade stenosis (LGS, <70%) at the site of stent overlap ...
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    23. Strut Coverage and Vessel Wall Response to a New-Generation Paclitaxel-Eluting Stent With an Ultrathin Biodegradable Abluminal Polymer: Optical Coherence Tomography Drug-Eluting Stent Investigation (OCTDESI)

      Strut Coverage and Vessel Wall Response to a New-Generation Paclitaxel-Eluting Stent With an Ultrathin Biodegradable Abluminal Polymer: Optical Coherence Tomography Drug-Eluting Stent Investigation (OCTDESI)
      Background—Polymer-coated drug-eluting stents are effective in preventing restenosis but have been associated with delayed healing and incomplete strut coverage. It is unknown whether paclitaxel-eluting stents (PES) with minimal biodegradable abluminal coating enhances strut coverage while preventing neointimal hyperplasia. Using optical coherence tomography (OCT) as a primary imaging modality, we assessed the proportion of uncovered struts at 6-month follow-up in PES coated with durable versus ultrathin (<1 µ m) biodegradable abluminal polymers. Methods and Results—In this pilot trial, 60 patients with de novo lesions (25 mm) in native coronary vessels were randomly assigned to receive either TAXUS Liberté PES ...
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    49-72 of 78 « 1 2 3 4 »
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    1. (78 articles) Hiram G. Bezerra
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    "Old" problems revisited; imaging the coronary in high resolution Use of optical coherence tomography for accurate characterization of atherosclerosis Optical coherence tomography (OCT) strut-level analysis of drug-eluting stents (DES) in human coronary bifurcations Semiautomatic segmentation and quantification of calcified plaques in intracoronary optical coherence tomography images Strut Coverage and Late Malapposition With Paclitaxel-Eluting Stents Compared With Bare Metal Stents in Acute Myocardial Infarction: OCT Substudy of the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) Plaque and thrombus evaluation by optical coherence tomography Congratulations to Zhao Wang from CWRU a Winner of a 2012 Student Travel Grant Award Consensus Standards for Acquisition, Measurement, and Reporting of Intravascular Optical Coherence Tomography Studies: A Report From the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation Feasibility and Safety of the Second-Generation, Frequency Domain Optical Coherence Tomography (FD-OCT): A Multicenter Study Duke University Engineering Professor Sina Farsiu Elected Fellow of the IEEE PhotoniCare Takes First Place at the 2019 HealthTECH Startup Competition Close Assessment and Testing for Chronic Graft Versus Host Disease, CATCH Study