1. Articles from Hiram G. Bezerra

    1-24 of 82 1 2 3 4 »
    1. An assessment of the quality of optical coherence tomography image acquisition

      An assessment of the quality of optical coherence tomography image acquisition

      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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    2. Fully automated plaque characterization in intravascular OCT images using hybrid convolutional and lumen morphology features

      Fully automated plaque characterization in intravascular OCT images using hybrid convolutional and lumen morphology features

      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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    3. Application and Evaluation of Highly Automated Software for Comprehensive Stent Analysis in Intravascular Optical Coherence Tomography

      Application and Evaluation of Highly Automated Software for Comprehensive Stent Analysis in Intravascular Optical Coherence Tomography

      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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    4. Optical Coherence Tomography-Based Modeling of Stent Deployment in Heavily Calcified Coronary Lesion

      Optical Coherence Tomography-Based Modeling of Stent Deployment in Heavily Calcified Coronary Lesion

      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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    5. Automated plaque characterization using deep learning on coronary intravascular optical coherence tomographic images

      Automated plaque characterization using deep learning on coronary intravascular optical coherence tomographic images

      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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    6. Automated A-line coronary plaque classification of intravascular optical coherence tomography images using handcrafted features and large datasets

      Automated A-line coronary plaque classification of intravascular optical coherence tomography images using handcrafted features and large datasets

      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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    7. Diagnostic accuracy of intracoronary optical coherence tomography-derived fractional flow reserve for assessment of coronary stenosis severity

      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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    8. Automated analysis of intravascular OCT image volumes

      Automated analysis of intravascular OCT image volumes

      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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    9. Analysis of optical tomography (OCT) images

      Analysis of optical tomography (OCT) images

      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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    10. New Volumetric Analysis Method for Stent Expansion and its Correlation With Final Fractional Flow Reserve and Clinical Outcome An ILUMIEN I Substudy

      New Volumetric Analysis Method for Stent Expansion and its Correlation With Final Fractional Flow Reserve and Clinical Outcome An ILUMIEN I Substudy

      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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    11. Optimizing Percutaneous Coronary Intervention in Calcified Lesions Insights From Optical Coherence Tomography of Atherectomy

      Optimizing Percutaneous Coronary Intervention in Calcified Lesions Insights From Optical Coherence Tomography of Atherectomy

      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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    12. Association of skin autofluorescence with plaque vulnerability evaluated by optical coherence tomography in patients with cardiovascular disease

      Association of skin autofluorescence with plaque vulnerability evaluated by optical coherence tomography in patients with cardiovascular disease

      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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    13. OCT Made Easy (Textbook)

      OCT Made Easy (Textbook)

      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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    14. 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

      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

      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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    15. Difference in Vascular Response between Sirolimus-eluting- and Everolimus-eluting Stents in Ostial Left Circumflex Artery after Unprotected Left Main as Observed by

      Difference in Vascular Response between Sirolimus-eluting- and Everolimus-eluting Stents in Ostial Left Circumflex Artery after Unprotected Left Main as Observed by

      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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    16. Failure Mechanisms and Neoatherosclerosis Patterns in Very Late Drug-Eluting and Bare-Metal Stent Thrombosis

      Failure Mechanisms and Neoatherosclerosis Patterns in Very Late Drug-Eluting and Bare-Metal Stent Thrombosis

      Background— There are few clinical studies on the pathophysiological mechanisms of very late stent thrombosis (VLST). We report optical coherence tomography findings in patients with VLST and compare the findings between bare-metal stents (BMS) and drug-eluting stents (DES). Methods and Results— We conducted a registry of stent thrombosis at 4 North American centers with optical coherence tomography imaging programs SAFE registry (The Study of Late Stent Failure Evaluated by OCT). Images were acquired in 61 patients (42 DES and 19 BMS) presenting with definite VLST. The median duration from implantation to VLST presentation was 51.4 months in the DES ...

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    17. Dextran or Saline Can Replace Contrast for Intravascular Optical Coherence Tomography in Lower Extremity Arteries

      Dextran or Saline Can Replace Contrast for Intravascular Optical Coherence Tomography in Lower Extremity Arteries

      Purpose: To examine the hypothesis that alternative flush media could be used for lower extremity optical coherence tomography (OCT) imaging in long lesions that would normally require excessive use of contrast. Methods: The OPTical Imaging Measurement of Intravascular Solution Efficacy (OPTIMISE) trial was a single-center, prospective study ( ClinicalTrials.gov identifier NCT01743872 ) that enrolled 23 patients (mean age 68±11 years; 14 men) undergoing endovascular intervention involving the superficial femoral artery. Four flush media (heparinized saline, dextran, carbon dioxide, and contrast) were used in succession in random order for each image pullback. Quality was defined as ≥270° visualization of vessel wall ...

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    18. Three-dimensional registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

      Three-dimensional registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

      Evidence suggests high-resolution, high-contrast, 100    frames / s 100  frames/s intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and three-dimensional (3-D) registration methods to provide validation of IVOCT pullback volumes using microscopic, color, and fluorescent cryo-image volumes with optional registered cryo-histology. A specialized registration method matched IVOCT pullback images acquired in the catheter reference frame to a true 3-D cryo-image volume. Briefly, an 11-parameter registration model including a polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition ...

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    19. Optical coherence tomography assessment of in-stent restenosis after percutaneous coronary intervention with two-stent technique in unprotected left main

      Optical coherence tomography assessment of in-stent restenosis after percutaneous coronary intervention with two-stent technique in unprotected left main

      Background Optical coherence tomography (OCT) has contributed to a better understanding of in-stent restenosis (ISR); however, studies evaluating ISR pattern after two-stent technique in unprotected left main (ULM) are lacking. We aim to evaluate the ISR pattern of proximal LAD and LCX after two-stent technique in ULM. Methods We performed OCT in 26 patients with isolated or combined ISR (identified by angiography as >50%) after two stent implantation in the proximal LCX and LAD. Finally, 13 LAD and 22 LCX ISR lesions underwent OCT assessments. OCT analyses were undertaken in the proximal segments of the LAD and LCX. In addition ...

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    1-24 of 82 1 2 3 4 »
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    1. (82 articles) Hiram G. Bezerra
    2. (78 articles) Case Western Reserve University
    3. (52 articles) Marco A. Costa
    4. (30 articles) Guilherme F. Attizzani
    5. (20 articles) Yusuke Fujino
    6. (19 articles) Abbot
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