1. Articles from Shengxian Tu

    1-24 of 38 1 2 »
    1. Impact of coronary plaque morphology on the precision of computational fractional flow reserve derived from optical coherence tomography imaging

      Impact of coronary plaque morphology on the precision of computational fractional flow reserve derived from optical coherence tomography imaging

      Background: Computational fractional flow reserve (FFR) was recently developed to expand the use of physiology-guided percutaneous coronary intervention (PCI). Nevertheless, current methods do not account for plaque composition. It remains unknown whether the numerical precision of computational FFR is impacted by the plaque composition in the interrogated vessels. Methods: This study is an observational, retrospective, cross-sectional study. Patients who underwent both optical coherence tomography (OCT) and FFR prior to intervention between August 2011 and October 2018 at Wakayama Medical University Hospital were included. All frames from OCT pullbacks were analyzed using a deep learning algorithm to obtain coronary plaque morphology ...

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    2. Physiologic and compositional coronary artery disease extension in patients with takotsubo syndrome assessed using artificial intelligence: an optical coherence tomography study

      Physiologic and compositional coronary artery disease extension in patients with takotsubo syndrome assessed using artificial intelligence: an optical coherence tomography study

      Background: Takotsubo syndrome (TTS) is an acute and reversible ventricular motion abnormality without epicardial coronary obstruction. Optical flow ratio (OFR) is an approach to evaluate the coronary stenosis significance based on three-dimensional optical coherence tomography (3D-OCT). The aim of this study is to utilize OCT and an artificial intelligence plaque characterization model to show the prevalence and composition of atherosclerotic disease in coronary vessels of patients with TTS. Methods: This is a retrospective and observational study which enrolled patients with TTS who underwent coronary angiography and OCT examination. OCT images were analyzed for tissue characterization and OFR computation using a ...

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    3. Combined Use of Multiple Intravascular Imaging Techniques in Acute Coronary Syndrome

      Combined Use of Multiple Intravascular Imaging Techniques in Acute Coronary Syndrome

      Recent advances in intravascular imaging techniques have made it possible to assess the culprit lesions of acute coronary syndrome (ACS) in the clinical setting. Intravascular ultrasound (IVUS) is the most commonly used intravascular imaging technique that provides cross-sectional images of coronary arteries. IVUS can assess plaque burden and vessel remodeling. Optical coherence tomography (OCT) is a high-resolution (10 μm) intravascular imaging technique that uses near-infrared light. OCT can identify key features of atheroma, such as lipid core and thin fibrous cap. Near-infrared spectroscopy (NIRS) can detect lipid composition by analyzing the near-infrared absorption properties of coronary plaques. NIRS provides a ...

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    4. Artificial intelligence and optical coherence tomography for the automatic characterisation of human atherosclerotic plaques

      Artificial intelligence and optical coherence tomography for the automatic characterisation of human atherosclerotic plaques

      Background: Intravascular optical coherence tomography (IVOCT) enables detailed plaque characterisation in vivo , but visual assessment is time-consuming and subjective. Aims: This study aimed to develop and validate an automatic framework for IVOCT plaque characterisation using artificial intelligence (AI). Methods: IVOCT pullbacks from five international centres were analysed in a core lab, annotating basic plaque components, inflammatory markers and other structures. A deep convolutional network with encoding-decoding architecture and pseudo-3D input was developed and trained using hybrid loss. The proposed network was integrated into commercial software to be externally validated on additional IVOCT pullbacks from three international core labs, taking the ...

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    5. Optical Coherence Tomography-Derived Changes in Plaque Structural Stress Over the Cardiac Cycle: A New Method for Plaque Biomechanical Assessment

      Optical Coherence Tomography-Derived Changes in Plaque Structural Stress Over the Cardiac Cycle: A New Method for Plaque Biomechanical Assessment

      Introduction: Cyclic plaque structural stress has been hypothesized as a mechanism for plaque fatigue and eventually plaque rupture. A novel approach to derive cyclic plaque stress in vivo from optical coherence tomography (OCT) is hereby developed. Materials and Methods: All intermediate lesions from a previous OCT study were enrolled. OCT cross-sections at representative positions within each lesion were selected for plaque stress analysis. Detailed plaque morphology, including plaque composition, lumen and internal elastic lamina contours, were automatically delineated. OCT-derived vessel and plaque morphology were included in a 2-dimensional finite element analysis, loaded with patient-specific intracoronary pressure tracing data, to calculate ...

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    6. Optical coherence tomography and coronary revascularization: from indication to procedural optimization

      Optical coherence tomography and coronary revascularization: from indication to procedural optimization

      Angiography alone is the most commonly used imaging modality for guidance of percutaneous coronary interventions. Angiography is limited, however, by several factors, including that it only portrays a low resolution, two-dimensional outline of the lumen and does not inform on plaque composition and functional stenosis severity. Optical coherence tomography (OCT) is an intracoronary imaging technique that has superior spatial resolution compared to all other imaging modalities. High-resolution imaging of the vascular wall enables precise measurement of vessel wall and luminal dimensions, more accurately informing about the anatomic severity of epicardial stenoses, and also provides input for computational models to assess ...

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    7. Comprehensive appraisal of cardiac motion artefact in optical coherence tomography

      Comprehensive appraisal of cardiac motion artefact in optical coherence tomography

      Background: The relation between cardiac motion artefact (CMA) in optical coherence tomography (OCT) and the phases of cardiac cycle is unclear. Methods: Optical coherence tomography pullbacks containing metallic stents were co-registered with angiography and retrospectively analyzed. The beginning of three phases, namely ejection, rapid-inflow and diastasis, was identified in angiography. Rotation, shortening, elongation and repetition were qualitatively labelled as CMA artefacts. Platforms with coaxial longitudinal connectors (ML8 and Magmaris) entered a quantitative sub-study, consisting of measuring the length of their connector at the beginning of each phase. Results: A total of 261 stents (127 patients) were analyzed, including 105 stents ...

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    8. Automatic Coregistration Between Coronary Angiography and Intravascular Optical Coherence Tomography

      Automatic Coregistration Between Coronary Angiography and Intravascular Optical Coherence Tomography

      This study sought to evaluate a novel approach for automatic coregistration of optical coherence tomography (OCT) and coronary angiography. Lumen diameters and side branches from both coronary angiography and OCT were used to create 2 feature sets. Subsequently, a 2-step coregistration approach was performed on the feature sets for matching of each OCT cross section on the angiographic centerline. For validation, all side branches with 1.0 mm diameter were identi fied and used as paired fiduciary landmarks. Geographical error was de fi ned as the distance between the automatically coregistered and the true-paired landmarks. Altogether 212 vessels from 181 ...

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    9. Usefulness of optical coherence tomography with angiographic coregistration in the guidance of coronary stent implantation

      Usefulness of optical coherence tomography with angiographic coregistration in the guidance of coronary stent implantation

      Optical coherence tomography (OCT)-angiography coregistration during stent implantation may be useful to avoid geographical mismatch and incomplete lesion coverage. Untreated lipid-rich plaque at stent edge is associated with subsequent stent edge restenosis. The present study sought to compare the frequency of untreated lipid-rich plaque at the stent edge between OCT-guided percutaneous coronary intervention (PCI) with and without OCT-angiography coregistration. We investigated 398 patients who underwent OCT-guided stent implantation (n = 198 in the coregistration group, and n = 200 in the no coregistration group). In OCT after PCI, untreated lipid-lich plaque was identified by the maximum lipid arc > 180˚ in the ...

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    10. Optical Flow Ratio for Assessing Stenting Result and Physiological Significance of Residual Disease

      Optical Flow Ratio for Assessing Stenting Result and Physiological Significance of Residual Disease

      Background: Optical flow ratio (OFR) is a novel method for fast computation of fractional flow reserve (FFR) from optical coherence tomography (OCT) images. Aims: We aimed to evaluate the accuracy of OFR in predicting post-percutaneous coronary intervention (PCI) FFR and to evaluate the impact of stent expansion on within-stent OFR pressure drop (In-stent OFR). Methods: Post-PCI OFR was computed in patients with both OCT and FFR interrogation immediately after PCI. Calculation of post-PCI OFR (called simulated residual OFR) from pre-PCI OCT pullbacks after elimination of the stenotic segment by virtual stenting was performed in a subgroup of patients who had ...

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    11. Automatic Characterisation of Human Atherosclerotic Plaque Composition from Intravascular Optical Coherence Tomography Using Artificial Intelligence

      Automatic Characterisation of Human Atherosclerotic Plaque Composition from Intravascular Optical Coherence Tomography Using Artificial Intelligence

      Background Intravascular optical coherence tomography (IVOCT) enables detailed plaque characterisation in-vivo, but visual assessment is time-consuming and subjective. Aims This study aims to develop and validate an automatic framework for IVOCT plaque characterisation using artificial intelligence (AI). Methods IVOCT pullbacks from 5 international centres were analysed in a corelab, annotating basic plaque components, inflammatory markers and other structures. A deep convolutional network with encoding-decoding architecture and pseudo-3D input was developed and trained using hybrid loss. The proposed network was integrated into commercial software to be externally validated on additional IVOCT pullbacks from three international corelabs, taking the consensus among corelabs ...

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    12. Comparison of Optical Flow Ratio and Fractional Flow Ratio in Stent-Treated Arteries Immediately After Percutaneous Coronary Intervention

      Comparison of Optical Flow Ratio and Fractional Flow Ratio in Stent-Treated Arteries Immediately After Percutaneous Coronary Intervention

      Background: Optical flow ratio (OFR) is a recently developed method for functional assessment of coronary artery disease based on computational fluid dynamics of vascular anatomical data from intravascular optical coherence tomography (OCT). The purpose of this study was to investigate the relationship between OFR and fractional flow reserve (FFR) in stent-treated arteries immediately after percutaneous coronary intervention (PCI). Methods and Results: The OFR and FFR were measured in 103 coronary arteries immediately after successful PCI with a stent. An increase in the OFR and FFR values within the stent was defined as in-stent ∆OFR and ∆FFR, respectively. The values of ...

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    13. Identification of the type of stent with three-dimensional optical coherence tomography: the SPQR study

      Identification of the type of stent with three-dimensional optical coherence tomography: the SPQR study

      Background: The ability of optical coherence tomography (OCT) to identify specific types of stent has never been systematically studied. Methods and results: A series of 212 consecutive patients with OCT from six international centres were retrospectively screened, finding 294 metallic stents or scaffolds in 146 patients. The sample was analysed by two blinded operators, applying a dedicated protocol in 4 steps to identify the type of stent: 1) 3D and automatic strut detection (ASD), 2) 3D tissue view, 3) Longitudinal view with ASD, 4) Mode “stent only” and ASD. The protocol correctly identified 285 stents (96.9%, kappa 0.965 ...

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    14. Automatic stent reconstruction in optical coherence tomography based on a deep convolutional model

      Automatic stent reconstruction in optical coherence tomography based on a deep convolutional model

      Intravascular optical coherence tomography (IVOCT) can accurately assess stent apposition and expansion, thus enabling the optimisation of a stenting procedure to minimize the risk of device failure. This paper presents a deep convolutional based model for automatic detection and segmentation of stent struts. The input of pseudo-3D images aggregated the information from adjacent frames to refine the probability of strut detection. In addition, multi-scale shortcut connections were implemented to minimize the loss of spatial resolution and refine the segmentation of strut contours. After training, the model was independently tested in 21,363 cross-sectional images from 170 IVOCT image pullbacks. The ...

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    15. Diagnostic accuracy and reproducibility of optical flow ratio for functional evaluation of coronary stenosis in a prospective series

      Diagnostic accuracy and reproducibility of optical flow ratio for functional evaluation of coronary stenosis in a prospective series

      Background: Evaluating prospectively the feasibility, accuracy and reproducibility of optical flow ratio (OFR), a novel method of computational physiology based on optical coherence tomography (OCT). Methods and results: Sixty consecutive patients (76 vessels) underwent prospectively OCT, angiography-based quantitative flow ratio (QFR) and fractional flow ratio (FFR). OFR was computed offline in a central core-lab by analysts blinded to FFR. OFR was feasible in 98.7% of the lesions and showed excellent agreement with FFR (ICCa = 0.83, r = 0.83, slope = 0.80, intercept = 0.17, kappa = 0.84). The area under curve to predict an FFR ≤ 0.80 was ...

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    16. Comparison of Diagnostic Performance of Intracoronary Optical Coherence Tomography-based and Angiography-based Fractional Flow Reserve for Evaluation of Coronary Stenosis

      Comparison of Diagnostic Performance of Intracoronary Optical Coherence Tomography-based and Angiography-based Fractional Flow Reserve for Evaluation of Coronary Stenosis

      Aims: To evaluate the diagnostic performance of OCT-based optical flow ratio (OFR) in unselected patients and compare it with angiography-based quantitative flow ratio (QFR), using wire-based FFR as reference standard. Methods and results: All patients with OCT and FFR assessment prior to revascularization were analyzed. OFR and QFR were computed in blinded fashion and compared with FFR, all applying same cut-off value of ≤0.80 to define ischemia. Paired comparison between OFR and QFR was performed in 212 vessels from 181 patients. Average FFR was 0.82±0.10 and 40.1% vessels had FFR≤0.80. OFR showed significant ...

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    17. Fractional flow reserve in clinical practice: from wire-based invasive measurement to image-based computation

      Fractional flow reserve in clinical practice: from wire-based invasive measurement to image-based computation

      Fractional flow reserve (FFR) and instantaneous wave-free ratio are the present standard diagnostic methods for invasive assessment of the functional significance of epicardial coronary stenosis. Despite the overall trend towards more physiology-guided revascularization, there remains a gap between guideline recommendations and the clinical adoption of functional evaluation of stenosis severity. A number of image-based approaches have been proposed to compute FFR without the use of pressure wire and induced hyperaemia. In order to better understand these emerging technologies, we sought to highlight the principles, diagnostic performance, clinical applications, practical aspects, and current challenges of computational physiology in the catheterization laboratory ...

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    18. 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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    19. In-stent fractional flow reserve variations and related optical coherence tomography findings: the FFR–OCT co-registration study

      In-stent fractional flow reserve variations and related optical coherence tomography findings: the FFR–OCT co-registration study

      We sought to assess in-stent variations in fractional flow reserve (FFR) in patients with previous percutaneous coronary intervention (PCI) and to associate any drop in FFR with findings by optical coherence tomography (OCT) imaging. Suboptimal post-PCI FFR values were previously associated with poor outcomes. It is not known to which extent in-stent pressure loss contributes to reduced FFR. In this single-arm observational study, 26 patients who previously underwent PCI with drug-eluting stent or scaffold implantation were enrolled. Motorized FFR pullback during continuous intravenous adenosine infusion and OCT assessments was performed. Post-PCI FFR < 0.94 was defined as suboptimal. At a ...

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    20. Anatomical and functional assessment of Tryton bifurcation stent before and after final kissing balloon dilatation: Evaluations by three-dimensional coronary angiography, optical coherence tomography imaging and fractional flow reserve

      Anatomical and functional assessment of Tryton bifurcation stent before and after final kissing balloon dilatation: Evaluations by three-dimensional coronary angiography, optical coherence tomography imaging and fractional flow reserve

      Objectives To assess the anatomical and functional impact of final kissing balloon inflation (FKBI) after implantation of a dedicated bifurcation stent system. Background Current evidence suggests clinical benefit of FKBI in patients undergoing bifurcation dilatation using the Tryton side branch stent (Tryton-SBS). We hypothesized that FKBI improves anatomical reconstruction and functional results of bifurcation treated by Tryton-SBS. Methods An unselected group of patients with complex bifurcation coronary lesions undergoing percutaneous coronary intervention (PCI) with Tryton-SBS underwent paired anatomical assessment with two- and three-dimensional quantitative coronary analysis (2D- and 3D-QCA), and optical coherence tomography (OCT), including 3D reconstruction before and after ...

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      Mentions: K. U. Leuven
    21. Advances in three-dimensional coronary imaging and computational fluid dynamics: is virtual fractional flow reserve more than just a pretty picture?

      Advances in three-dimensional coronary imaging and computational fluid dynamics: is virtual fractional flow reserve more than just a pretty picture?

      Percutaneous coronary intervention (PCI) has shown a high success rate in the treatment of coronary artery disease. The decision to perform PCI often relies on the cardiologist’s visual interpretation of coronary lesions during angiography. This has inherent limitations, particularly due to the low resolution and two-dimensional nature of angiography. State-of-the-art modalities such as three-dimensional quantitative coronary angiography, optical coherence tomography and invasive fractional flow reserve (FFR) may improve clinicians’ understanding of both the anatomical and physiological importance of coronary lesions. While invasive FFR is the gold standard technique for assessment of the haemodynamic significance of coronary lesions, recent studies ...

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    22. Impact of Side Branch Modeling on Computation of Endothelial Shear Stress in Coronary Artery Disease Coronary Tree Reconstruction by Fusion of 3D Angiography and OCT

      Impact of Side Branch Modeling on Computation of Endothelial Shear Stress in Coronary Artery Disease Coronary Tree Reconstruction by Fusion of 3D Angiography and OCT

      Background Computational fluid dynamics allow virtual evaluation of coronary physiology and shear stress (SS). Most studies hitherto assumed the vessel as a single conduit without accounting for the flow through side branches. Objectives This study sought to develop a new approach to reconstruct coronary geometry that also computes outgoing flow through side branches in hemodynamic and biomechanical calculations, using fusion of optical coherence tomography (OCT) and 3-dimensional (3D) angiography. Methods Twenty-one patients enrolled in the DOCTOR (Does Optical Coherence Tomography Optimize Revascularization) fusion study underwent OCT and 3D-angiography of the target vessel (9 left anterior descending, 2 left circumflex, 10 ...

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    23. Co-registration of Optical Coherence Tomography and X-ray Angiography in Percutaneous Coronary Intervention. The Does Optical Coherence Tomography Optimize Revascularization (DOCTOR) Fusion Study

      Co-registration of Optical Coherence Tomography and X-ray Angiography in Percutaneous Coronary Intervention. The Does Optical Coherence Tomography Optimize Revascularization (DOCTOR) Fusion Study

      Background Intracoronary imaging provides accurate lesion delineation and precise measurements for sizing and positioning of coronary stents. During percutaneous coronary intervention (PCI), it may be challenging to identify corresponding segments between intracoronary imaging and angiography. Computer based online co-registration may aid the target segment identification. Methods The DOCTOR Fusion study was a prospective, single arm, observational study including patients admitted for elective PCI. Optical coherence tomography (OCT) was acquired pre-stent implantation for sizing of stents. The operator subsequently indicated on the angiogram the target area as identified by OCT. Computer based co-registration was performed on-line immediately after pre-stent acquisition to ...

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