1. Articles in category: Cardiology

    481-504 of 3009 « 1 2 ... 18 19 20 21 22 23 24 ... 124 125 126 »
    1. Texas Engineering Experiment Station Receives NIH Grant for Morphological and Molecular Imaging System for In Vivo Atherosclerosis Research

      Texas Engineering Experiment Station Receives NIH Grant for Morphological and Molecular Imaging System for In Vivo Atherosclerosis Research

      Texas Engineering Experiment Station Receives a 2015 NIH Grant for Morphological and Molecular Imaging System for In Vivo Atherosclerosis Research. The Principal invesigator is Brian Applegate. The program began in 2012 and ends in 2017. Below is a summary of the proposed work.

      Atherosclerosis is the leading cause of morbidity and mortality in the United States and is characterized as a systemic, progressive disease process in which the arterial wall thickens through a process of inflammation, oxidative stress, and dyslipidemia. This process leads to plaque formation and flow limitation in the vessel lumen. The sudden rupture of this arterial plaques ...

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    2. First Optical Coherence Tomography Follow-up of Coronary Bifurcation Lesions Treated by Drug-Eluting Balloons

      First Optical Coherence Tomography Follow-up of Coronary Bifurcation Lesions Treated by Drug-Eluting Balloons

      Background. A strategy of percutaneous bifurcation intervention with provisional bare-metal stent (BMS) implantation followed by drug-eluting balloon (DEB) treatment represents a valuable opportunity in patients not compliant with long-duration dual-antiplatelet therapy. We used optical coherence tomography (OCT) to assess coronary bifurcation lesions treated by BMS and DEB, and secondarily, to better explore the association between stent geometry and tissue coverage. Methods. Twelve patients underwent frequency-domain OCT 6 months after undergoing percutaneous bifurcation intervention with BMS implantation followed by kissing DEB. The same type of BMS was correspondingly implanted in silicone bifurcation models and scanned by microcomputed tomography. Results. Overall, a ...

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    3. Relationship Between Subclinical Cardiac Troponin I Elevation and Culprit Lesion Characteristics Assessed by Optical Coherence Tomography in Patients Undergoing Elective Percutaneous Coronary Intervention

      Relationship Between Subclinical Cardiac Troponin I Elevation and Culprit Lesion Characteristics Assessed by Optical Coherence Tomography in Patients Undergoing Elective Percutaneous Coronary Intervention

      Background— The prevalence of subclinical, cardiac troponin I (cTnI) elevation in stable patients undergoing elective percutaneous coronary intervention and its relationship to culprit lesion characteristics assessed by optical coherence tomography (OCT) are unknown. Methods and Results— We studied 206 native de novo culprit coronary lesions from 206 patients with stable angina pectoris who underwent OCT before elective percutaneous coronary intervention. Patients were divided into 2 groups according to the presence (cTnI group; n=47; 22.8%) or absence (non-cTnI group; n=159; 77.2%) of cTnI ≥0.03 ng/mL at admission. The clinical and OCT findings were compared between ...

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    4. Slow-Flow Phenomenon After Paclitaxel-Coated Balloon Angioplasty: Findings From Optical Coherence Tomography and Coronary Angioscopy

      Slow-Flow Phenomenon After Paclitaxel-Coated Balloon Angioplasty: Findings From Optical Coherence Tomography and Coronary Angioscopy

      In case 1, a 60-year-old man underwent a 4.0-mm × 12-mm bare-metal stent (BMS) implantation in the proximal left anterior descending coronary artery. Six months after BMS implantation, a coronary angiogram demonstrated in-stent restenosis (ISR) at the proximal portion of the stent (Figure 1 ). Frequency-domain optical coherence tomography (FD-OCT) revealed homogeneous neointima (Figure 1 ) and coronary angioscopy (CAS) revealed white neointimal coverage at the ISR site (Figure 1 ). The lesion was dilated using a 3.5 × 13-mm conventional balloon catheter at 16 atm. After balloon angioplasty, Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 was achieved, and intracoronary electrocardiography did ...

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    5. Endovascular therapy for fibromuscular dysplasia of the bilateral external iliac arteries visualized with optical coherence tomography

      Endovascular therapy for fibromuscular dysplasia of the bilateral external iliac arteries visualized with optical coherence tomography

      Background : Fibromuscular dysplasia (FMD) is a non-inflammatory, non-atherosclerotic, degenerative vascular disease that most frequently affects renal and carotid arteries in women aged 30–50 years, and rarely complicating arteries of the lower limbs. Case Report : A 60-year-old woman was admitted with intermittent claudication of both legs. We performed pelvic and bilateral lower-extremities angiography, which revealed that the bilateral external iliac arteries (EIAs) had the ‘string of beads’ appearance with a diagnosis of FMD. Endovascular therapy (EVT) was performed for the bilateral EIAs. Optical coherence tomography (OCT) images showed thickening and thinning of the middle layer, while three-dimensional OCT images showed ...

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    6. One-year coverage by optical coherence tomography of a bioresorbable scaffold neocarina: is it safe to discontinue dual antiplatelet therapy?

      One-year coverage by optical coherence tomography of a bioresorbable scaffold neocarina: is it safe to discontinue dual antiplatelet therapy?

      This is a case reporting on the 1-year coverage status of side-branch bioresorbable vascular scaffold (BVS) struts protruding in main vessels. The 1-year optical coherence tomography demonstrated a tissue neocarina forming over protruding BVS struts, although the coverage was widely inhomogeneous and perhaps still incomplete in some portions, thus leading to cautious extension of dual antiplatelet therapy beyond one year.

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    7. Optical Coherence Tomography of Dialysis Graft after Angioplasty

      Optical Coherence Tomography of Dialysis Graft after Angioplasty

      Neointimal hyperplasia, the major cause of arteriovenous graft (AVG) stenosis, is not directly visualized by angiography. A 60-year-old woman on hemodialysis presented with a clotted AVG 30 days after its creation. Following percutaneous thrombectomy, angiography revealed severe (> 50%) stenosis at the graft (G)-vein (V) anastomosis (arrow in Fig 1 ). Optical coherence tomography performed using an intravascular Dragonfly catheter (St. Jude Medical, Westford, Massachusetts) delineated the intima in bright yellow.

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    8. Vascular wall stress during intravascular optical coherence tomography imaging

      Vascular wall stress during intravascular optical coherence tomography imaging

      Biomechanical properties of arterial wall is crucial for understanding the changes in the cardiovascular system. Catheters are used during intravascular optical coherence tomography (IVOCT) imaging. The presence of a catheter alters the flow field, pressure distribution and frictional resistance to flow in an artery. In this paper, we first study the transmural stress distribution of the catheterized vessel. COMSOL (COMSOL 4.4) was used to simulate the blood flow induced deformation in a catheterized vessel. Blood is modeled as an incompressible Newtonian fluid. Stress distribution from an three-layer vascular model with an eccentric catheter are simulated, which provides a general ...

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    9. Low eicosapentaenoic acid to arachidonic acid ratio is associated with thin-cap fibroatheroma determined by optical coherence tomography

      Low eicosapentaenoic acid to arachidonic acid ratio is associated with thin-cap fibroatheroma determined by optical coherence tomography

      Background A low eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio is known to be associated with cardiovascular events. However, the relationship between the EPA/AA ratio and coronary plaque vulnerability assessed by optical coherence tomography (OCT) has not been examined thoroughly. This study examined the relationship between the EPA/AA ratio and coronary plaque vulnerability assessed by OCT in patients with acute coronary syndrome (ACS). Methods We evaluated 59 ACS patients who had undergone percutaneous coronary intervention using OCT. We divided them into 2 groups according to OCT findings—those with and without thin-cap fibroatheroma (TCFA)—and compared the EPA ...

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    10. The butler did it! A very late stent thrombosis of TAXUS evaluated with Optical Coherence Tomography

      The butler did it! A very late stent thrombosis of TAXUS evaluated with Optical Coherence Tomography

      A 64 years old male smoker, obese, diabetic non-insulin dependent, dyslipidaemia, presented to our Emergency Department for new onset typical chest pain and EKG signs of an acute anterior ST elevation myocardial infarction. He had an history of a percutaneous coronary interventions to his three vessels with stents TAXUS in 2006 when he presented with stable angina. He performed dual antiplatelet therapy (DAT) for six months, then he assumed aspirin alone.

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    11. Accuracy of OCT, Grayscale IVUS, and Their Combination for the Diagnosis of Coronary TCFA An Ex Vivo Validation Study

      Accuracy of OCT, Grayscale IVUS, and Their Combination for the Diagnosis of Coronary TCFA An Ex Vivo Validation Study

      Objectives This study sought to assess the accuracy of optical coherence tomography (OCT), gray-scale intravascular ultrasound (IVUS), and their combination for detecting thin-cap fibroatheromas (TCFA). Background The extent to which the imaging characteristics of OCT and IVUS correlate with histologically defined TCFA is unknown. Methods IVUS and OCT examinations identified focal plaques in 165 coronary arteries from 60 autopsy hearts. A total of 685 pairs of images of OCT and IVUS were compared with histology. By OCT, a TCFA was defined as a signal-poor region with diffuse borders and cap thickness <65 μm. By IVUS, a TCFA was defined by ...

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    12. Optical Coherence Tomography during carotid artery stenting: A new niche application?

      Optical Coherence Tomography during carotid artery stenting: A new niche application?

      In the past decades angiography has been the keystone to assess vascular anatomy, leading to the development of largely applied percutaneous revascularisation techniques. However, angiography can only provide a limited analysis of lumen profile without the possibility to disclose vessel wall characteristics and composition of atherosclerotic lesions. Intravascular ultrasound (IVUS), introduced in the early ‘90ies, followed more then a decade after by optical coherence tomography (OCT) provide information about intravascular anatomy that far exceeds the level of detail obtained from conventional angiography.

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    13. Late-acquired scaffold malapposition and discontinuity that may be attributable to pathological coronary ectasia: Insights from optical coherence tomography

      Late-acquired scaffold malapposition and discontinuity that may be attributable to pathological coronary ectasia: Insights from optical coherence tomography

      A 69-year-old man presenting with exertional angina, underwent successful percutaneous coronary intervention to the proximal mid-segment of the left circumflex coronary artery with implantation of two Absorb bioresorbable scaffolds (BRS; Abbott vascular, Santa Clara, CA) (Fig. 1A). He returned 16-months later with recurrent symptoms. Coronary angiography revealed focal ectasia and significant in-scaffold restenosis (Fig. 1B). Optical coherence tomography imaging of the ectatic lesion demonstrated a large scaffold lumen diameter (3.74 × 5.04 mm), which was above the upper dilatation limit of the 3.0 mm diameter scaffold and greater than the reference vessel diameter on intravascular ultrasound at the ...

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    14. Different optical coherence tomography findings for intracoronary stripe-like filling defects on coronary angiogram in patients with acute coronary syndrome

      Different optical coherence tomography findings for intracoronary stripe-like filling defects on coronary angiogram in patients with acute coronary syndrome

      Stripe-like radiolucent filling defects visualized by conventional coronary angiogram (CAG) usually suggest coronary artery dissection. However, recent endovascular imaging technique with high resolution power such as optical coherence tomography (OCT) makes more detailed intraluminal lesion characterization possible, compared with the conventional CAG, and attests to possibilities of being different clinical situation [1]. We report that stripe-like radiolucent filling defects on CAG proved to have different pathophysiologies by OCT in patients with acute coronary syndrome.

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      Mentions: Korea University
    15. A Honeycomb-Like Structure in Chronic Total Occlusion Demonstrated by Frequency-Domain Optical Coherence Tomography

      A Honeycomb-Like Structure in Chronic Total Occlusion Demonstrated by Frequency-Domain Optical Coherence Tomography

      A 68 year-old male with a history of hypertension and current smoking was admitted due to exertional chest pain. Coronary angiography (CAG) showed a chronic total occlusion (CTO) in the left circumflex artery with collateral supply from the right coronary artery (Fig. 1). PCI was performed in this lesion as patient has normal left ventricular function. After crossing the lesion with guide wire (Gaia 2nd) and micro catheter, frequency-domain optical coherence tomography (FD-OCT) (ILUMIEN™ OCT Imaging System, St Jude Medical, Inc, St Paul, Minnesota) was performed

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    16. New techniques of intravessel imaging in coronary atherosclerosis

      New techniques of intravessel imaging in coronary atherosclerosis

      Intravascular imaging modalities are currently adopted to circumvent angiographic limitations. The present overview is aimed at describing the principal techniques used by an interventional cardiologist to assess both coronary atherosclerotic plaques and stent deployment results. Optical coherence tomography (OCT), intravascular ultrasound (IVUS), and near-infrared spectroscopy are currently available to address these issues. These techniques are characterized by specific advantages and limitations, making each of those applicable for specific purposes. Offline software programmes have been developed to further characterize plaque tissue, highlighting the macrophage presence or unfold coronary stent in a three-dimensional view by a carpet view. Although IVUS and OCT ...

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      Mentions: Francesco Prati
    17. Evaluation of hemodynamics changes during interventional stent placement using Doppler optical coherence tomography

      Evaluation of hemodynamics changes during interventional stent placement using Doppler optical coherence tomography

      Carotid atherosclerosis is a critical medical concern that can lead to ischemic stroke. Local hemodynamic patterns have also been associated with the development of atherosclerosis, particularly in regions with disturbed flow patterns such as bifurcations. Traditionally, this disease was treated using carotid endarterectomy, however recently there is an increasing trend of carotid artery stenting due to its minimally invasive nature. It is well known that this interventional technique creates changes in vasculature geometry and hemodynamic patterns due to the interaction of stent struts with arterial lumen, and is associated with complications such as distal emboli and restenosis. Currently, there is ...

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    18. Association between tissue characteristics assessed with optical coherence tomography and mid-term results after percutaneous coronary intervention for in-stent restenosis lesions: a comparison between balloon angioplasty, paclitaxel-coated balloon dilata

      Association between tissue characteristics assessed with optical coherence tomography and mid-term results after percutaneous coronary intervention for in-stent restenosis lesions: a comparison between balloon angioplasty, paclitaxel-coated balloon dilata

      Aims Morphological assessment of neointimal tissue using optical coherence tomography (OCT) is important for clarifying the pathophysiology of in-stent restenosis (ISR) lesions. The aim of this study was to determine the impact of OCT findings on recurrence of ISR after paclitaxel-coated balloon (PCB) dilatation compared with plain old balloon angioplasty (POBA). Methods and results Between July 2008 and May 2012, we performed percutaneous coronary intervention for 214 ISR lesions using POBA + PCB (146 lesions, PCB group) or POBA only (68 lesions, POBA group). Morphological assessment of neointimal tissue using OCT, including assessment of restenotic tissue structure and restenotic tissue backscatter ...

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    19. Automated measurement of stent strut coverage in intravascular optical coherence tomography

      Automated measurement of stent strut coverage in intravascular optical coherence tomography

      Optical coherence tomography (OCT) is a non-invasive, cross-sectional imaging modality that has become a prominent imaging method in percutaneous intracoronary intervention. We present an automated detection algorithm for stent strut coordinates and coverage in OCT images. The algorithm for stent strut detection is composed of a coordinate transformation from the polar to the Cartesian domains and application of second derivative operators in the radial and the circumferential directions. Local region-based active contouring was employed to detect lumen boundaries. We applied the method to the OCT pullback images acquired from human patients in vivo to quantitatively measure stent strut coverage. The ...

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    20. 3-D Stent Detection in Intravascular OCT Using a Bayesian Network and Graph Search

      3-D Stent Detection in Intravascular OCT Using a Bayesian Network and Graph Search

      Worldwide, many hundreds of thousands of stents are implanted each year to revascularize occlusions in coronary arteries. Intravascular optical coherence tomography (OCT) is an important emerging imaging technique, which has the resolution and contrast necessary to quantitatively analyze stent deployment and tissue coverage following stent implantation. Automation is needed, as current, it takes up to 16 hours to manually analyze hundreds of images and thousands of stent struts from a single pullback. For automated strut detection, we used image formation physics and machine learning via a Bayesian network, and 3-D knowledge of stent structure via graph search. Graph search was ...

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    21. Application of optical coherence tomography attenuation imaging for quantification of optical properties in medulloblastoma

      Application of optical coherence tomography attenuation imaging for quantification of optical properties in medulloblastoma

      The hemodynamic environment is known to play a crucial role in the progression, rupture, and treatment of intracranial aneurysms. Currently there is difficulty assessing and measuring blood flow profiles in vivo. An emerging high resolution imaging modality known as split spectrum Doppler optical coherence tomography (ssDOCT) has demonstrated the capability to quantify hemodynamic patterns as well as arterial microstructural changes. In this study, we present a novel in vitro method to acquire precise blood flow patterns within a patient- specific aneurysm silicone flow models using ssDOCT imaging. Computational fluid dynamics (CFD) models were generated to verify ssDOCT results.

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    22. Noninvasive Optical Coherence Tomography Could Track Vascular Disease in Diabetics

      Noninvasive Optical Coherence Tomography Could Track Vascular Disease in Diabetics

      Columbia research team creating novel technology to improve diagnosis of peripheral arterial disease A comparison between a cross section of a foot in a healthy and a diabetic patient with peripheral artery disease. The optical tomographic imaging technology shows blood perfusion, or the absence of perfusion, in the issue. Approximately 8 to 12 million people in the United States alone are suffering from peripheral arterial disease (PAD) , a common vascular problem that is also one of the most serious complications of diabetes. Andreas Hielscher, professor of biomedical engineering, electrical engineering and radiology (physics) at Columbia Engineering, is developing a novel ...

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