1. Articles from Takashi Akasaka

    1-24 of 132 1 2 3 4 5 6 »
    1. Optical coherence tomography in coronary atherosclerosis assessment and intervention

      Optical coherence tomography in coronary atherosclerosis assessment and intervention

      Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing ...

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    2. 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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    3. 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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    4. Evaluation of coronary plaques and atherosclerosis using optical coherence tomography

      Evaluation of coronary plaques and atherosclerosis using optical coherence tomography

      Introduction: Coronary angiography (CAG) is the standard modality for assessing coronary stenosis; however, it has limitations in assessing coronary plaque morphology. Optical coherence tomography (OCT) is a high-resolution (10-20μm) light-based intravascular imaging technique that can identify more detailed coronary plaque morphology compared to other intravascular imaging modalities. OCT is remarkable for characterizing fibrous, fibrocalcific, and lipid-rich plaques. The capabilities of OCT are well suited for discriminating three types of unstable plaque morphologies underlying coronary thrombosis, such as plaque rupture, erosion, and calcified nodules. The high resolution of OCT makes it possible to identify important features of vulnerable plaques, such ...

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    5. Optical coherence tomography detection of vulnerable plaques at high risk of developing acute coronary syndrome

      Optical coherence tomography detection of vulnerable plaques at high risk of developing acute coronary syndrome

      Aims: The ability of optical coherence tomography (OCT) to detect plaques at high risk of developing acute coronary syndrome (ACS) remains unclear. The aim of this study was to evaluate the association between non-culprit plaques characterized as both lipid-rich plaque (LRP) and thin-cap fibroatheroma (TCFA) by OCT and the risk of subsequent ACS events at the lesion level. Methods and results: In 1378 patients who underwent OCT, 3533 non-culprit plaques were analysed for the presence of LRP (maximum lipid arc > 180°) and TCFA (minimum fibrous cap thickness < 65 μm). The median follow-up period was 6 years [interquartile range (IQR): 5-9 ...

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    6. Impact of Optical Coherence Tomography Imaging on Decision-Making During Percutaneous Coronary Intervention in Patients Presented With Acute Coronary Syndromes

      Impact of Optical Coherence Tomography Imaging on Decision-Making During Percutaneous Coronary Intervention in Patients Presented With Acute Coronary Syndromes

      Background: Optical coherence tomography (OCT) provides valuable information to guide percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) regarding lesion preparation, stent sizing, and optimization. The aim of the present study was to compare lumen expansion of stent-treated lesions immediately after the procedure for ACS between OCT-guided PCI and angiography-guided PCI.Methods and Results:This study investigated stent-treated lesions immediately after PCI for ACS by using quantitative coronary angiography in 390 patients; 260 patients with OCT-guided PCI and 130 patients with angiography-guided PCI. Before stenting, the frequency of pre-dilatation and thrombus aspiration were not different between the OCT-guided and ...

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    7. Saline as an alternative to radio-contrast for optical coherence tomography guided percutaneous coronary intervention: A prospective comparison

      Saline as an alternative to radio-contrast for optical coherence tomography guided percutaneous coronary intervention: A prospective comparison

      Objectives: To do a quantitative comparison of saline and contrast Frequency domain optical coherence tomography (FD-OCT) during percutaneous coronary intervention (PCI) optimisation. Methods: 13 pairs of OCT runs were analysed, wherein each pair consisted of a contrast run and a heparinized saline run taken in the same coronary artery at the same position. Quantitative analysis was done comparing minimal lumen area (MLA), proximal reference diameter (PRD), distal reference diameter (DRD) and percentage area stenosis (AS) at the same anatomical location. Lesion morphologies, rendered stent view and 3D reconstruction were compared for image clarity. Result: The saline OCT runs resulted in ...

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    8. Prevalence, Features, and Prognosis of Artery-to-Artery Embolic ST-Segment-Elevation Myocardial Infarction: An Optical Coherence Tomography Study

      Prevalence, Features, and Prognosis of Artery-to-Artery Embolic ST-Segment-Elevation Myocardial Infarction: An Optical Coherence Tomography Study

      Background The major underlying mechanisms contributing to acute coronary syndrome are plaque rupture, plaque erosion, and calcified nodule. Artery-to-artery embolic myocardial infarction (AAEMI) was defined as ST-segment-elevation myocardial infarction caused by migrating thrombus formed at the proximal ruptured plaque. The aim of this study was to investigate the prevalence and clinical features of AAEMI by using optical coherence tomography. Methods and Results This study retrospectively enrolled 297 patients with ST-segment-elevation myocardial infarction who underwent optical coherence tomography before percutaneous coronary intervention. Patients were divided into 4 groups consisting of plaque rupture, plaque erosion, calcified nodule, and AAEMI according to optical ...

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    9. NIRS-IVUS for Differentiating Coronary Plaque Rupture, Erosion and Calcified Nodule in Acute Myocardial Infarction

      NIRS-IVUS for Differentiating Coronary Plaque Rupture, Erosion and Calcified Nodule in Acute Myocardial Infarction

      Objectives This study sought to investigate the ability of combined near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS) to differentiate plaque rupture (PR), plaque erosion (PE), or calcified nodule (CN) in acute myocardial infarction (AMI). Background Most acute coronary syndromes occur from coronary thrombosis based on PR, PE, or CN. In vivo differentiation among PR, PE, and CN is a major challenge for intravascular imaging. Methods The study enrolled 244 patients with AMI who had a de novo culprit lesion in a native coronary artery. The culprit lesions were assessed by both NIRS-IVUS and optical coherence tomography (OCT). Maximum lipid core burden ...

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    10. Supporting evidence for ST-segment elevation myocardial infarction from optical coherence tomography

      Supporting evidence for ST-segment elevation myocardial infarction from optical coherence tomography

      A 56-year-old male with current smoking and dyslipidemia was admitted to our hospital because of anterior ST-segment elevation myocardial infarction (STEMI). Echocardiogram showed akinesis in the apex of the left ventricle, and the ejection fraction was 55%. There was no evidence of atrial fibrillation, cardiac shunts or any cardiac thrombus. He had no history of the emotional stress, cocaine intake or thrombophilia. And, also there was no episode that suspected coronary spasm. After administration of aspirin 200mg and prasugrel 20mg, the emergent coronary angiogram (CAG) was performed. CAG showed the total occlusion at the distal portion of left anterior descending ...

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    11. 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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    12. OPtical Coherence Tomography Guided Coronary Stent IMplantation Compared to Angiography: A Multicenter Randomized TriaL in PCI

      OPtical Coherence Tomography Guided Coronary Stent IMplantation Compared to Angiography: A Multicenter Randomized TriaL in PCI

      AIMS: Randomized trials have demonstrated improvement in clinical outcomes with intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) compared with angiography-guided PCI. The ILUMIEN III trial demonstrated non-inferiority of an optical coherence tomography (OCT)- versus IVUS-guided PCI strategy in achieving similar post-PCI lumen dimensions. ILUMIEN IV is a large-scale, multicenter, randomized trial designed to demonstrate the superiority of OCT- versus angiography-guided stent implantation in patients with high-risk clinical characteristics (diabetes) and/or complex angiographic lesions in achieving larger post-PCI lumen dimensions and improving clinical outcomes. METHODS AND RESULTS: ILUMIEN IV is a prospective, single-blind clinical investigation that will randomize between ...

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    13. Outcomes of Optical Coherence Tomography Compared With Intravascular Ultrasound and With Angiography to Guide Coronary Stent Implantation: One-Year Results from the ILUMIEN III: OPTIMIZE PCI trial

      Outcomes of Optical Coherence Tomography Compared With Intravascular Ultrasound and With Angiography to Guide Coronary Stent Implantation: One-Year Results from the ILUMIEN III: OPTIMIZE PCI trial

      Aims: In the ILUMIEN III trial, among 450 randomised patients with non-complex lesions undergoing percutaneous coronary intervention (PCI), optical coherence tomography (OCT) guidance led to greater stent expansion than angiography guidance, similar minimal stent area compared to both intravascular ultrasound (IVUS) guidance and angiography guidance, and lower rates of uncorrected dissection and malapposition than both IVUS guidance and angiography guidance. Whether these differences impact clinical outcomes is unknown. Methods and results : OCT-guided PCI, using an external elastic lamina-based protocol, was compared to operator-directed IVUS-guided or angiography-guided PCI. Target lesion failure (TLF) and major adverse cardiovascular events (MACE) at 12 months ...

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    14. Optical Coherence Tomography Comparison of Percutaneous Coronary Intervention Among Plaque Rupture, Erosion, and Calcified Nodule in Acute Myocardial Infarction

      Optical Coherence Tomography Comparison of Percutaneous Coronary Intervention Among Plaque Rupture, Erosion, and Calcified Nodule in Acute Myocardial Infarction

      Background: Acute myocardial infarction (AMI) is caused by coronary plaque rupture (PR), plaque erosion (PE), or calcified nodule (CN). We used optical coherence tomography (OCT) to compare stent expansion immediately after primary percutaneous coronary intervention (PCI) in patients with AMI caused by PR, PE, or CN. Methods and Results: In all, 288 AMI patients were assessed by OCT before and immediately after PCI, performed with OCT guidance according to OPINION criteria for stent sizing and optimization. The frequency of OCT-identified PR (OCT-PR), OCT-PE, and OCT-CN was 172 (60%), 82 (28%), and 34 (12%), respectively. Minimum stent area was smallest in ...

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    15. Extent of the difference between microcatheter and pressure wire-derived fractional flow reserve and its relation to optical coherence tomography-derived parameters

      Extent of the difference between microcatheter and pressure wire-derived fractional flow reserve and its relation to optical coherence tomography-derived parameters

      Background Although previous studies demonstrated that microcatheter-derived fractional flow reserve (mc-FFR) tends to overestimate lesion severity compared to pressure wire-derived FFR (pw-FFR), the clinical utility of mc-FFR remains obscure. The extent of differences between the two FFR systems and its relation to a lesion-specific parameter remain unknown. In this study, we sought to compare mc-FFR with pw-FFR and determine the lower and upper mc-FFR cut-offs predicting ischemic and non-ischemic stenosis, using an ischemic and a clinical FFR threshold of 0.75 and 0.80 as references, respectively. We further explored optical coherence tomography (OCT) parameters influencing the difference in FFR ...

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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. A Local Multi-Layer Model for Tissue Classification of in-vivo Atherosclerotic Plaques in Intravascular Optical Coherence Tomography

      A Local Multi-Layer Model for Tissue Classification of in-vivo Atherosclerotic Plaques in Intravascular Optical Coherence Tomography

      Clinical researches show that the morbidity of coronary artery disease (CAD) is gradually increasing in many countries every year, and it causes hundreds of thousands of people all over the world dying for each year. As the optical coherence tomography with high resolution and better contrast applied to the lesion tissue investigation of human vessel, many more micro-structures of the vessel could be easily and clearly visible to doctors, which help to improve the CAD treatment effect. Manual qualitative analysis and classification of vessel lesion tissue are time-consuming to doctors because a single-time intravascular optical coherence (IVOCT) data set of ...

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    18. Expert consensus statement for quantitative measurement and morphological assessment of optical coherence tomography

      Expert consensus statement for quantitative measurement and morphological assessment of optical coherence tomography

      In this document, the methods for the quantitative measurement and morphological assessment of optical coherence tomography (OCT)/optical frequency domain imaging images (OFDI) are briefly summarized. The focus is on the clinical application of OCT/OFDI to guide percutaneous coronary interventions.

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    19. Intracoronary pressure increase due to contrast injection for optical coherence tomography imaging

      Intracoronary pressure increase due to contrast injection for optical coherence tomography imaging

      Background Optical coherence tomography (OCT) requires intracoronary injection of contrast media to remove blood from the field of view during image acquisition. Contrast injection may cause a temporal increase in intracoronary pressure. The aim of this study was to compare the intracoronary pressure during contrast injection between OCT and coronary angiography . Methods We measured intracoronary pressure by using a pressure guidewire during contrast injection for OCT and angiography in 30 coronary arteries (mean fractional flow reserve = 0.90 ± 0.03). Contrast media was injected into coronary artery through the guiding catheter by using a mechanical injector pump. Results Intracoronary pressure ...

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    20. Clinical use of intracoronary imaging. Part 2: acute coronary syndromes, ambiguous coronary angiography findings, and guiding interventional decision-making: an expert consensus document of the European Association of Percutaneous Cardiovascular Intervent

      Clinical use of intracoronary imaging. Part 2: acute coronary syndromes, ambiguous coronary angiography findings, and guiding interventional decision-making: an expert consensus document of the European Association of Percutaneous Cardiovascular Intervent

      This consensus document is the second of two reports summarizing the views of an expert panel organized by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) on the clinical use of intracoronary imaging including intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near infrared spectroscopy (NIRS)-IVUS. Beyond guidance of stent selection and optimization of deployment, invasive imaging facilitates angiographic interpretation and may guide treatment in acute coronary syndrome. Intravascular imaging can provide additional important diagnostic information when confronted with angiographically ambiguous lesions and allows assessment of plaque morphology enabling identification of vulnerability characteristics. This second document focuses on useful ...

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    21. Early and mid-term vascular responses to optical coherence tomography guided everolimus-eluting stent implantation in stable coronary artery disease

      Early and mid-term vascular responses to optical coherence tomography guided everolimus-eluting stent implantation in stable coronary artery disease

      Background Analysis of pooled clinical data has shown the safety of 3 months of dual antiplatelet therapy (DAPT) with everolimus-eluting cobalt–chromium stents (Co-Cr EESs). This study evaluated early and mid-term vascular responses to Co-Cr EESs in patients with stable coronary artery disease (CAD). Methods The MECHANISM-Elective trial (NCT02014818) is a multicenter optical coherence tomography (OCT) registry. Enrolled patients were evaluated by OCT immediately after EES implantation (post), were prospectively allocated to either 1 month (n = 50) or 3 months (n = 50) OCT follow-up, and then received a 12 months OCT evaluation. The incidences of intrastent thrombus (IS-Th) and irregular ...

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    22. Plaque burden can be assessed using intravascular optical coherence tomography and a dedicated automated processing algorithm: a comparison study with intravascular ultrasound

      Plaque burden can be assessed using intravascular optical coherence tomography and a dedicated automated processing algorithm: a comparison study with intravascular ultrasound

      Aims Plaque burden (PB) measurement using intravascular optical coherence tomography (IVOCT) is currently thought to be inferior to intravascular ultrasound (IVUS). We developed an automated IVOCT image processing algorithm to enhance the external elastic lamina (EEL) contour. Thus, we investigated the accuracies of standard IVOCT and an IVOCT enhancement algorithm for measuring PB using IVUS as the reference standard. Methods and results The EEL-enhancement algorithm combined adaptive attenuation compensation, exponentiation, angular registration, and image averaging using three sequential frames. In two different laboratories with intravascular imaging expertise, PB was quantified on 200 randomized, matched IVOCT and IVUS images by four ...

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    23. Imaging assessment and accuracy in coronary artery autopsy: comparison of frequency-domain optical coherence tomography with intravascular ultrasound and histology

      Imaging assessment and accuracy in coronary artery autopsy: comparison of frequency-domain optical coherence tomography with intravascular ultrasound and histology

      ptical coherence tomography (OCT) is a coronary artery imaging technique with high resolution. Second-generation frequency-domain OCT (FD-OCT) technology allows safer and faster clinical application compared with first-generation time-domain OCT (TD-OCT). Only limited validation studies compare FD-OCT with other modes of analysis: histology, which is the current gold standard, and intravascular ultrasound (IVUS). This study therefore aims to demonstrate the accuracy of FD-OCT images compared with IVUS and histology. FD-OCT and IVUS images were acquired from 203 segments from 31 coronary arteries obtained at autopsy from 20 cadavers. Of these, 30 randomly-selected pairs were used to create three classifications of plaque ...

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    24. Optical coherence tomography in varying aetiologies of renal artery stenosis: a case series

      Optical coherence tomography in varying aetiologies of renal artery stenosis: a case series

      Background Renal artery stenosis (RAS) is a common cause of secondary hypertension. The most common aetiology is atherosclerosis; however, other causes like fibromuscular dysplasia (FMD) and Takayasu arteritis (TA) are also frequently encountered. The lesion characteristics and its response to percutaneous intervention depend upon the aetiology of RAS. Optical coherence tomography (OCT) is an excellent imaging modality to analyse coronary lesions during percutaneous coronary interventions. The data regarding the utility of OCT in renal artery imaging is limited, consisting of a few case reports. Case summary We hereby report four cases of RAS, each of different aetiology (atherosclerotic, FMD, post-transplant ...

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