1. Articles from Hirosada Yamamoto

    1-17 of 17
    1. 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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    2. 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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    3. Impact of Culprit Plaque and Atherothrombotic Components on Incomplete Stent Apposition in Patients With ST-Elevation Myocardial Infarction Treated With Everolimus-Eluting Stents – An OCTAVIA Substudy –

      Impact of Culprit Plaque and Atherothrombotic Components on Incomplete Stent Apposition in Patients With ST-Elevation Myocardial Infarction Treated With Everolimus-Eluting Stents – An OCTAVIA Substudy –

      Background: The role of culprit plaque and related atherothrombotic components on incomplete stent apposition (ISA) occurrence after primary percutaneous coronary intervention (p-PCI) is unknown. Methods and Results: ST-segment elevation myocardial infarction (STEMI) patients undergoing p-PCI with an everolimus-eluting stent were prospectively investigated with optical coherence tomography (OCT) of the infarct-related artery before, after stenting and at 9 months. OCT data, aspirated thrombus and serum inflammatory biomarkers were analyzed. 114 patients with 114 lesions were evaluated. Acute ISA occurred in 82 lesions (71.9%), preferentially in larger vessels with a median area of 0.2 mm 2 . The presence of thrombus ...

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    4. The clinical characteristics and prognosis of lesions with in-stent eccentric tissue proliferation and strong signal attenuation detected by optical coherence tomography

      The clinical characteristics and prognosis of lesions with in-stent eccentric tissue proliferation and strong signal attenuation detected by optical coherence tomography

      There are still some patients who require repeat revascularization despite of drug-eluting stent (DES) implantation. The present study aimed to investigate the relationship between optical coherence tomography (OCT) findings and recurring target lesion revascularization (TLR) after percutaneous coronary intervention (PCI) for in-stent restenosis (ISR). We reviewed 50 patients (54 coronary lesions) who underwent PCI for ISR, which included 25 DES-ISR lesions. The PCI strategy depended on the interventionalist’s discretion, and DES implantation was performed for 38 (70 %) lesions. Tissue characteristics were assessed qualitatively and quantitatively using the frame showing maximal lumen narrowing (minimal lumen area). In qualitative analysis, OCT ...

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    5. Comparison of scanning electron microscopy and optical coherence tomography (OCT) for imaging of coronary bifurcation stents

      Comparison of scanning electron microscopy and optical coherence tomography (OCT) for imaging of coronary bifurcation stents

      Background: Optical coherence tomography (OCT) is a new intracoronary imaging modality that has excellent resolution and image quality and has been used to image neointimal coverage after stent implantation. OCT has been compared to histologic, intravascular ultrasound, and scanning electron microscopy (SEM) studies. However, OCT has not been compared with SEM for imaging stent coverage over side branches. Objective: The aim of this study was to compare OCT with scanning electron microscopy (SEM) in imaging neointimal coverage over stent struts bridging coronary side-branch ostia. Methods: Using a balloon-overstretch in-stent restenosis model, we deployed 38 everolimus-eluting stents across coronary bifurcations in ...

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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. Optical coherence tomography for characterization of cardiac allograft vasculopathy after heart transplantation (OCTCAV study)

      Optical coherence tomography for characterization of cardiac allograft vasculopathy after heart transplantation (OCTCAV study)

      BACKGROUND Optical coherence tomography (OCT) is a novel intravascular imaging modality with excellent spatial resolution. This study explored the utility of OCT in cardiac transplantation for the detection and characterization of early changes associated with coronary allograft vasculopathy (CAV). METHODS Fifteen consecutive patients, 1 to 4 years after transplant with no angiographic evidence of CAV, underwent successful OCT imaging using the Fourier-domain OCT system (C7-XR, St. Jude Medical, St. Paul, MN) in the left anterior descending artery. Analysis included measurements of the lumen, intima, and media layers, and characterization of atherosclerotic plaques. Patients were stratified by intima-to-media (I/M) ratio ...

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    10. Volumetric assessment of lesion severity with optical coherence tomography: relationship with fractional flow reserve

      Volumetric assessment of lesion severity with optical coherence tomography: relationship with fractional flow reserve

      Aims: Frequency-domain optical coherence tomography (FD-OCT) provides a rapid tomographic scan of a coronary vessel, with an accurate reconstruction of its lumen profile. An FD-OCT-based metric that corresponds more closely with physiological significance of lesions may enable more precise guidance of interventional procedures. The aim of this feasibility study was to evaluate a new method for quantifying coronary lesion severity that estimates hyperaemic flow resistance of branched vessel segments imaged by FD-OCT. Methods and results: An analytical flow model was developed that relates fractional flow reserve (FFR) to the vascular resistance ratio (VRR), a measure of blood flow resistance derived ...

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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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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    16. Quantitative coronary optical coherence tomography image analysis for the signal attenuation observed in-stent restenotic tissue

      Quantitative coronary optical coherence tomography image analysis for the signal attenuation observed in-stent restenotic tissue
      Pivotal clinical trials have shown that the drug-eluting stent (DES) ameliorated mid-term target lesion revascularization rate . Nevertheless, late catch up phenomenon is the growing concern in the patients with DES . Previous study has shown that the restenotic tissue after DES implantation shows thrombus formation or inflammatory cells even at chronic phase. Thromborestenosis should be the concern for the prevention of late stent thrombosis .
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    17. Incidence and significance of the pseudo stent strut in optical coherence tomography analysis for coronary artery stents

      Incidence and significance of the pseudo stent strut in optical coherence tomography analysis for coronary artery stents
      Introduction: Quantitative optical coherence tomography (OCT) analysis is about to be relevant for the correct assessment of incomplete stent apposition which can result to late stent thrombosis. Nevertheless, the pseudo stent struts (PS), which show the strong signal same as the true strut, are sometimes seen at odd positions in the lumen and locate at the same distance from the image wire as a true strut. PS may be produced by the distorted beam and interfere accurate analysis. Our aim was to investigate the incidence of PS. Methods: We created a simple phantom model (2.5 mm-coronary artery stent apposed ...
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    1-17 of 17
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    Incidence and significance of the pseudo stent strut in optical coherence tomography analysis for coronary artery stents Quantitative coronary optical coherence tomography image analysis for the signal attenuation observed in-stent restenotic tissue Utilization of frequency domain optical coherence tomography and fractional flow reserve to assess intermediate coronary artery stenoses: conciliating anatomic and physiologic information Volumetric quantification of fibrous caps using intravascular optical coherence tomography 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 assessment of lesion severity with optical coherence tomography: relationship with fractional flow reserve 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 In vivo evaluation of corneal biomechanical properties by optical coherence elastography at different cross-linking irradiances The Association of Optical Coherence Tomography Results With Neuroimaging Signs and Some Clinical Parameters in Idiopathic Intracranial Hypertension