1. Articles from Emile Mehanna

    1-15 of 15
    1. 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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    2. 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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    3. 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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    4. 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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    5. 3D registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

      3D registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

      High resolution, 100 frames/sec intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and 3D registration methods, to provide validation of IVOCT pullback volumes using microscopic, brightfield and fluorescent cryoimage volumes, with optional, exactly registered cryo-histology. The innovation was a method to match an IVOCT pullback images, acquired in the catheter reference frame, to a true 3D cryo-image volume. Briefly, an 11-parameter, polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition. Virtual catheter parameters were optimized to ...

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    6. Serial assessment of vessel interactions after drug-eluting stent implantation in unprotected distal left main coronary artery disease using frequency-domain optical coherence tomography

      Serial assessment of vessel interactions after drug-eluting stent implantation in unprotected distal left main coronary artery disease using frequency-domain optical coherence tomography

      Objectives This study sought to assess stent-vessel interactions after drug-eluting stent (DES) implantation in unprotected left main coronary artery (ULM) by frequency-domain optical coherence tomography (FD-OCT). Background Percutaneous coronary intervention using DES in ULM has been increasingly performed in routine practice. Recently, FD-OCT assessments of DES-vessel interactions have been used as surrogates for DES safety; however, there are no FD-OCT studies in ULM. Methods We prospectively enrolled 33 consecutive patients with ULM disease treated with sirolimus- (n = 11) and everolimus-eluting stents (n = 22). FD-OCT assessments were performed post-percutaneous coronary intervention and at 9-month follow-up. Three different segments of ULM were ...

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    7. Incidence, Predictors, Morphological Characteristics, and Clinical Outcomes of Stent Edge Dissections Detected by Optical Coherence Tomography

      Incidence, Predictors, Morphological Characteristics, and Clinical Outcomes of Stent Edge Dissections Detected by Optical Coherence Tomography

      Objectives This study sought to investigate the frequency, predictors, and detailed qualitative and quantitative assessment of optical coherence tomography (OCT)-detected stent edge dissections. Its impact on subsequent management and clinical outcomes were also investigated. Background OCT is a high-resolution imaging modality that can lead to more frequent recognition and accurate assessment of vascular injuries during percutaneous coronary intervention (PCI). Methods From September 2010 to June 2011, all patients with OCT post-PCI were enrolled. Edge dissections were defined as disruptions of the arterial lumen surface in both the 5-mm distal and proximal stent edges. Qualitative and quantitative analyses of all ...

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    8. Volumetric Characterization of Human Coronary Calcification by Frequency-Domain Optical Coherence Tomography.

      Volumetric Characterization of Human Coronary Calcification by Frequency-Domain Optical Coherence Tomography.

      Background: Coronary artery calcification (CAC) presents unique challenges for percutaneous coronary intervention. Calcium appears as a signal-poor region with well-defined borders by frequency-domain optical coherence tomography (FD-OCT). The objective of this study was to demonstrate the accuracy of intravascular FD-OCT to determine the distribution of CAC. Methods and Results: Cadaveric coronary arteries were imaged using FD-OCT at 100-μm frame interval. Arteries were subsequently frozen, sectioned and imaged at 20-μm intervals using the Case Cryo-Imaging automated system TM . Full volumetric co-registration between FD-OCT and cryo-imaging was performed. Calcium area, calcium-lumen distance (depth) and calcium angle were traced on every ...

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    9. Frequency-domain optical coherence tomography assessment of unprotected left main coronary artery disease - a comparison with intravascular ultrasound

      Frequency-domain optical coherence tomography assessment of unprotected left main coronary artery disease - a comparison with intravascular ultrasound

      Objectives: To investigate safety and feasibility of imaging unprotected left main (ULM) using frequency-domain optical coherence tomography (FD-OCT) compared with intravascular ultrasound (IVUS). Background: IVUS has been used to assess and guide percutaneous coronary intervention (PCI) of ULM disease. FD-OCT offers 10-fold higher axial resolution than IVUS and its high-speed image acquisition obviates the need for proximal balloon occlusion. Methods: We prospectively enrolled 35 consecutive patients with ULM disease. FD-OCT and IVUS assessments were attempted pre- and post-PCI and compared in regards to safety, ability to image the region of interest (ROI), number of pullbacks, volume of contrast and ability ...

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    10. 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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    11. 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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    12. Imaging a spiral dissection of the superficial femoral artery in high resolution with optical coherence tomography—Seeing is believing

      Imaging a spiral dissection of the superficial femoral artery in high resolution with optical coherence tomography—Seeing is believing

      Optical coherence tomography (OCT) offers an alternative to intravascular ultrasound (IVUS) for endovascular imaging. Clinical and research applications for OCT have emerged in percutaneous coronary intervention (PCI), however, OCT has not found similar utility in peripheral arterial interventions. Early generation time-domain OCT systems required arterial occlusion to create the blood free environment needed for image acquisition and could not reliably scan vessel diameters encountered in the peripheral circulation. However, the frequency-domain OCT (FD-OCT) system currently FDA approved for use in the United States does not require arterial occlusion to generate images and permits a greater scan diameter allowing for exploratory ...

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    13. 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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    1-15 of 15
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    In vitro validation of new Fourier-domain optical coherence tomography Utilization of frequency domain optical coherence tomography and fractional flow reserve to assess intermediate coronary artery stenoses: conciliating anatomic and physiologic information Imaging a spiral dissection of the superficial femoral artery in high resolution with optical coherence tomography—Seeing is believing Unrestricted utilization of frequency domain optical coherence tomography in coronary interventions Serial Evaluation of Vascular Response After Implantation of a New Sirolimus-Eluting Stent with Bioabsorbable Polymer (MISTENT): An Optical Coherence Tomography and Histopathological Study Frequency-domain optical coherence tomography assessment of unprotected left main coronary artery disease - a comparison with intravascular ultrasound Volumetric Characterization of Human Coronary Calcification by Frequency-Domain Optical Coherence Tomography. Incidence, Predictors, Morphological Characteristics, and Clinical Outcomes of Stent Edge Dissections Detected by Optical Coherence Tomography 3D registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation Optimizing Percutaneous Coronary Intervention in Calcified Lesions Insights From Optical Coherence Tomography of Atherectomy Retinal Vascular Features in Ocular Blunt Trauma by Optical Coherence Tomography Angiography Non-invasive imaging of a choroidal macrovessel