1. Articles from marc d. feldman

    1-24 of 41 1 2 »
    1. Assessment of Vascular Patency and Inflammation with Intravascular Optical Coherence Tomography in Patients with Superficial Femoral Artery Disease Treated with Zilver PTX Stents

      Assessment of Vascular Patency and Inflammation with Intravascular Optical Coherence Tomography in Patients with Superficial Femoral Artery Disease Treated with Zilver PTX Stents

      Purpose Zilver PTX nitinol self-expanding drug-eluting stent with paclitaxel coating is effective for treatment of superficial femoral artery (SFA) disease. However, as with any stent, it induces a measure of vascular inflammatory response. The current clinical trial (NCT02734836) aimed to assess vascular patency, remodeling, and inflammatory markers with intravascular optical coherence tomography (OCT) in patients with SFA disease treated with Zilver PTX stents. Methods Serial OCT examinations were performed in 13 patients at baseline and 12-month follow-up. Variables evaluated included neointimal area, luminal narrowing, thrombus area, stent expansion as well as measures of inflammation including, peri-strut low-intensity area (PLIA), macrophage ...

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    2. Laser brain cancer surgery in a xenograft model guided by optical coherence tomography

      Laser brain cancer surgery in a xenograft model guided by optical coherence tomography

      Higher precision surgical devices are needed for tumor resections near critical brain structures. The goal of this study is to demonstrate feasibility of a system capable of precise and bloodless tumor ablation. An image-guided laser surgical system is presented for excision of brain tumors in vivo in a murine xenograft model. The system combines optical coherence tomography (OCT) guidance with surgical lasers for high-precision tumor ablation (Er:YAG) and microcirculation coagulation (Thulium (Tm) fiber laser). Methods: A fluorescent human glioblastoma cell line was injected into mice and allowed to grow four weeks. Craniotomies were performed and tumors were imaged with ...

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    3. Apparatus and methods for identifying and evaluating bright spot indications observed through optical coherence tomography

      Apparatus and methods for identifying and evaluating bright spot indications observed through optical coherence tomography

      Exemplary embodiments of the present disclosure include apparatus and methods for identifying bright spot indications observed through optical coherence tomography. The indications can be evaluated, for example, to link risk factors or other conditions to clinically relevant outcomes

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    4. Diagnosis of Thin-Capped Fibroatheromas in Intravascular Optical Coherence Tomography Images Effects of Light Scattering

      Diagnosis of Thin-Capped Fibroatheromas in Intravascular Optical Coherence Tomography Images Effects of Light Scattering

      Background— Intravascular optical coherence tomography (IVOCT) images are recorded by detecting light backscattered within coronary arteries. We hypothesize that non–thin-capped fibroatheroma (TCFA) causes may scatter light to create the false appearance of IVOCT TCFA. Methods and Results— Ten human cadaver hearts were imaged with IVOCT (n=14 coronary arteries). IVOCT and histological TCFA images were coregistered and compared. Of 21 IVOCT TCFAs (fibrous cap <65 μm, lipid arc >1 quadrant), only 8 were true histological TCFA. Foam cell infiltration was responsible for 70% of false IVOCT TCFA and caused both thick-capped fibroatheromas to appear as TCFA, and the appearance ...

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    5. Fourier optics analysis of phase-mask-based path-length-multiplexed optical coherence tomography

      Fourier optics analysis of phase-mask-based path-length-multiplexed optical coherence tomography

      Imaging below fingertip surface might be a useful alternative to the traditional fingerprint sensing since the internal finger features are more reliable than the external ones. One of the most promising subsurface imaging technique is optical coherence tomography (OCT), which, however, has to acquire 3-D data even when a single en face image is required. This makes OCT inherently slow for en face imaging and produce unnecessary large data sets. Here we demonstrate that full-field optical coherence tomography (FF-OCT) can be used to produce en face images of sweat pores and internal fingerprints, which can be used for the identification ...

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    6. Clinical utility of quantitative bright spots analysis in patients with acute coronary syndrome: an optical coherence tomography study

      Clinical utility of quantitative bright spots analysis in patients with acute coronary syndrome: an optical coherence tomography study

      To investigate the clinical significance of bright spots in coronary plaque detected by optical coherence tomography (OCT) in patients with coronary artery disease. We identified 112 patients [acute coronary syndromes (ACS): n = 50, stable angina pectoris (SAP): n = 62] who underwent OCT imaging of the culprit lesion. A novel OCT algorithm was applied to detect bright spots representing the juxtaposition of a variety of plaque components including macrophages. The density of bright spots within the most superficial 250 μm of the vessel wall was measured at the site of culprit lesion. Bright spot density in the culprit lesion was significantly ...

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    7. Translating Intravascular Optical Coherence Tomography from a Research to a Clinical Tool

      Translating Intravascular Optical Coherence Tomography from a Research to a Clinical Tool

      Intravascular optical coherence tomography (IVOCT) continues to be a hot topic as a method for studying vulnerable plaque in research laboratories across the globe. It is also growing in popularity as a tool for interventional cardiologists to guide percutaneous coronary intervention (PCI). The power of IVOCT for diagnosis of thin-capped fibroatheromas (TCFAs) has yet to receive mainstream clinical attention due to the fact that clinicians still do not have a protocol to follow if TCFA are identified and that TCFA identification requires extensive training in IVOCT image analysis—it is not yet an automated process. In this review, we will ...

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    8. Can Multimodal Invasive Imaging Be Used to Predict Periprocedural Myocardial Infarctions?

      Can Multimodal Invasive Imaging Be Used to Predict Periprocedural Myocardial Infarctions?

      More than 1 million percutaneous coronary interventions (PCIs) are performed per year in the United States. Although technological advances have significantly improved outcomes following PCI, 5% to 44% of PCI patients still experience periprocedural myocardial infarction (PMI). PMI can be either macro-sized (coronary dissection or occlusion of a side branch) or microvascular such as distal embolization and/or microvascular plugging. PMIs have recently been defined as Type 4a: cardiac troponin (cTn) levels >5× elevation above the 99th percentile upper reference limit (URL), but only if the baseline cTn levels were normal (≤99th percentile URL) 1 . In addition to the elevated ...

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    9. Detection of plaque structure and composition using OCT combined with two-photon luminescence (TPL) imaging

      Detection of plaque structure and composition using OCT combined with two-photon luminescence (TPL) imaging

      Background and Objectives Atherosclerosis and plaque rupture leads to myocardial infarction and stroke. A novel hybrid optical coherence tomography (OCT) and two-photon luminescence (TPL) fiber-based imaging system was developed to characterize tissue constituents in the context of plaque morphology. Study Design/Materials and Methods Ex vivo coronary arteries (34 regions of interest) from three human hearts with atherosclerotic plaques were examined by OCT–TPL imaging. Histological sections (4 μm in thickness) were stained with Oil Red O for lipid, Von Kossa for calcium, and Verhoeff–Masson Tri-Elastic for collagen/elastin fibers and compared with imaging results. Results Biochemical components in ...

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    10. Simultaneous morphological and biochemical endogenous optical imaging of atherosclerosis

      Simultaneous morphological and biochemical endogenous optical imaging of atherosclerosis

      Aims The aim of this study was to validate novel imaging technology for simultaneous morphological and biochemical endogenous optical imaging of coronary atherosclerotic plaque. Methods and results Optical coherence tomography (OCT) generates high-resolution 3D images of plaque morphology and endogenous fluorescence lifetime imaging microscopy (FLIM) characterizes biochemical composition. Both imaging modalities rely on plaque's intrinsic optical characteristics, making contrast agents unnecessary. A multimodal OCT/FLIM system was utilized to generate luminal biochemical maps superimposed on high-resolution (7 µm axial and 13 µm lateral) structural volumetric images. Forty-seven fresh postmortem human coronary segments were imaged: pathological intimal thickening (PIT, n ...

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    11. Intravascular optical coherence tomography light scattering artifacts: merry-go-rounding, blooming, and ghost struts

      Intravascular optical coherence tomography light scattering artifacts: merry-go-rounding, blooming, and ghost struts

      We sought to elucidate the mechanisms underlying two common intravascular optical coherence tomography (IV-OCT) artifacts that occur when imaging metallic stents: “merry-go-rounding” (MGR), which is an increase in strut arc length (SAL), and “blooming,” which is an increase in the strut reflection thickness (blooming thickness). Due to uncontrollable variables that occur in vivo , we performed an in vitro assessment of MGR and blooming in stented vessel phantoms. Using Xience V and Driver stents, we examined the effects of catheter offset, intimal strut coverage, and residual blood on SAL and blooming thickness in IV-OCT images. Catheter offset and strut coverage both ...

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    12. Evaluation of IVOCT imaging of coronary artery metallic stents with neointimal coverage

      Evaluation of IVOCT imaging of coronary artery metallic stents with neointimal coverage

      Accuracy of IVOCT for measurement of neointimal thickness and effect of neointima in the appearance of metallic struts in IVOCT images was investigated. Phantom vessels were constructed and coronary stents were deployed and covered with thick (250–400 μm) and thin (30–70 μm) phantom neointima. High resolution Micro-CT images of the stent struts were recorded as a gold standard. IVOCT images of the phantom vessels were acquired with various luminal blood scattering strengths and measured neointimal thicknesses from IVOCT and Micro-CT images were compared. In transparent lumen, comparison of IVOCT and Micro-CT neointima thickness measurements found no significant difference ...

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    13. Macrophages and intravascular optical coherence tomography bright spots: a quantitative study

      Macrophages and intravascular optical coherence tomography bright spots: a quantitative study

      Objectives We hypothesized that bright spots in intravascular optical coherence tomography (IVOCT) images may originate by co-localization of plaque materials of differing indices of refraction (IR). To quantitatively identify bright spots, we developed an algorithm that accounts for factors including tissue depth, distance from light source, and signal-to-noise ratio. We used this algorithm to perform a bright spot analysis of IVOCT images, and compared these results with histologic examination of matching tissue sections. Background Although bright spots are thought to represent macrophages in IVOCT images, studies of alternative etiologies have not been reported. Methods Fresh human coronary arteries (n=14 ...

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    14. Optical coherence tomography to guide below-the-knee endovascular interventions

      Optical coherence tomography to guide below-the-knee endovascular interventions

      Peripheral arterial disease remains a common cause of leg amputations causing significant morbidity and mortality. Data regarding below-the-knee endovascular interventions is scarce while long-term patency rates via different endovascular revascularization modalities remain limited. OCT offers excellent three dimension endothelial visualization; however its value to guide peripheral interventions has not been studied. We describe the use of OCT to guide endovascular below-the-knee interventions in order to achieve excellent OCT results.

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    15. Optical Coherent Tomography to guide below-the-knee endovascular interventions

      Optical Coherent Tomography to guide below-the-knee endovascular interventions

      Peripheral arterial disease remains a common cause of leg amputations causing significant morbidity and mortality. Data regarding below-the-knee endovascular interventions is scarce while long-term patency rates via different endovascular revascularization modalities remain limited. OCT offers excellent three dimension endothelial visualization; however its value to guide peripheral interventions has not been studied. We describe the use of OCT to guide endovascular below-the-knee interventions in order to achieve excellent OCT results.

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    16. Use of Optical Coherence Tomography During Superficial Femoral Artery Interventions

      Use of Optical Coherence Tomography During Superficial Femoral Artery Interventions

      Superficial femoral artery (SFA) disease accounts for approximately 40% of the symptomatic peripheral arterial disease and remains a common cause of critical limb ischemia and lower-extremity amputation. Optical coherence tomography (OCT) has been extensively studied in the coronary circulation; however, its use in the peripheral arterial circulation is scarce. We present two cases of OCT use as an ancillary imaging tool during SFA endovascular interventions

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    17. Intravascular optical coherence tomography measurement of size and apposition of metallic stents

      Intravascular optical coherence tomography measurement of size and apposition of metallic stents

      Effect of beam size and catheter position on the apparent size and apposition of metallic stent struts in IVOCT images were examined. Micro-CT data was employed to determine light - stent strut interactions. Simulated results suggest that location of the reflecting regions depend on relative orientation and position of stent struts to the IVOCT beam. Erroneous stent apposition measurements can occur when the IVOCT catheter is at an eccentric position. A method that mitigates stent strut apposition measurement errors is proposed.

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    18. Hemoglobin contrast in ultrasound and optical coherence tomography for diagnosing diseased tissue, cancers, and the like

      Hemoglobin contrast in ultrasound and optical coherence tomography for diagnosing diseased tissue, cancers, and the like

      A novel contrast mechanism for diagnosing diseased tissue using Ultrasound, Doppler Ultrasonography, Optical Coherence Tomography, or optical Doppler tomography coupled with an externally applied temporally oscillating high-strength magnetic field.

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    19. Dual-wavelength multifrequency photothermal wave imaging combined with optical coherence tomography for macrophage and lipid detection in atherosclerotic plaques using gold nanoparticles

      Dual-wavelength multifrequency photothermal wave imaging combined with optical coherence tomography for macrophage and lipid detection in atherosclerotic plaques using gold nanoparticles

      The objective of this study was to assess the ability of combined photothermal wave (PTW) imaging and optical coherence tomography (OCT) to detect, and further characterize the distribution of macrophages (having taken up plasmonic gold nanorose as a contrast agent) and lipid deposits in atherosclerotic plaques. Aortas with atherosclerotic plaques were harvested from nine male New Zealand white rabbits divided into nanorose- and saline-injected groups and were imaged by dual-wavelength (800 and 1210 nm) multifrequency (0.1, 1 and 4 Hz) PTW imaging in combination with OCT. Amplitude PTW images suggest that lateral and depth distribution of nanorose-loaded macrophages (confirmed ...

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    1-24 of 41 1 2 »
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    1. (41 articles) Marc D. Feldman
    2. (33 articles) University of Texas at Austin
    3. (30 articles) Thomas E. Milner
    4. (23 articles) University of Texas Health Science Center
    5. (6 articles) Leiden University
    6. (6 articles) Jouke Dijkstra
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