1. Articles from Antonius F. W. van der Steen

    1-19 of 19
    1. Motorized capsule for shadow-free OCT imaging and synchronous beam control

      Motorized capsule for shadow-free OCT imaging and synchronous beam control

      We demonstrate a tethered motorized capsule for unobstructed optical coherence tomography (OCT) imaging of the esophagus. By using a distal reflector design, we avoided the common shadow artifact induced by the motor wires. A synchronous driving technique features three types of beam-scanning modes of the capsule, i.e., circumferential beam scanning, localized beam scanning, and accurate beam positioning. We characterized these three modes and carried out ex vivo imaging experiments using the capsule. The results show that the capsule can potentially be a useful tool for diagnostic OCT imaging and OCT-guided biopsy and therapy of the esophagus.

      Read Full Article
    2. Feature Of The Week 09/10/2017: Thermo-elastic Optical Coherence Tomography

      Feature Of The Week 09/10/2017: Thermo-elastic  Optical Coherence Tomography

      The conventional OCT image contrast is derived from elastic scattering, and shows the internal structure of the sample. The determination of the tissue type in OCT images usually depends on the interpretation by the image reader. More accurate tissue type contrast may be achieved by new OCT-based imaging modalities, with sensitivity to other physical parameters than scattering alone. Phase-sensitive OCT can detect tissue motion on nanometer-to- micrometer length scales using the phase of the OCT signal. Depending on the nature of the excitation, different functional images can be reconstructed: a mechanical stimulus yields images of tissue elasticity (optical coherence elastography ...

      Read Full Article
    3. Thermo-elastic optical coherence tomography

      Thermo-elastic optical coherence tomography

      The absorption of nanosecond laser pulses induces rapid thermo-elastic deformation in tissue. A sub-micrometer scale displacement occurs within a few microseconds after the pulse arrival. In this Letter, we investigate the laser-induced thermo-elastic deformation using a 1.5 MHz phase-sensitive optical coherence tomography (OCT) system. A displacement image can be reconstructed, which enables a new modality of phase-sensitive OCT, called thermo-elastic OCT. An analysis of the results shows that the optical absorption is a dominating factor for the displacement. Thermo-elastic OCT is capable of visualizing inclusions that do not appear on the structural OCT image, providing additional tissue type information.

      Read Full Article
    4. EuroIntervention Automated characterisation of lipid core plaques in vivo by quantitative optical coherence tomography tissue type imaging

      EuroIntervention Automated characterisation of lipid core plaques in vivo by quantitative optical coherence tomography tissue type imaging

      Aims: Qualitative criteria for plaque tissue characterisation by OCT are well established, but quantitative methods lack systematic validation in vivo . High optical attenuation coefficient µ t has been associated with unstable plaque features, such as lipid core. The purpose of this study was to validate optical coherence tomography (OCT) attenuation imaging for tissue characterisation in vivo , specifically to detect lipid core in coronary atherosclerotic plaques, and to evaluate quantitatively the ability of OCT attenuation imaging to differentiate thin-cap (TCFA) and thick-cap fibroatheroma (FA). Methods and results: We prospectively enrolled 85 patients undergoing imaging of a native coronary segment by both OCT ...

      Read Full Article
    5. Optical coherence tomography attenuation imaging for lipid core detection: an ex-vivo validation study

      Optical coherence tomography attenuation imaging for lipid core detection: an ex-vivo validation study

      Lipid-core atherosclerotic plaques are associated with disease progression, procedural complications, and cardiac events. Coronary plaque lipid can be quantified in optical coherence tomography (OCT) pullbacks by measurement of lipid arcs and lipid lengths; parameters frequently used in clinical research, but labor intensive and subjective to analyse. In this study, we investigated the ability of quantitative attenuation, derived from intravascular OCT, to detect plaque lipid. Lipid cores are associated with a high attenuation coefficient. We compared the index of plaque attenuation (IPA), a local quantitative measure of attenuation, to the manually measured lipid score (arc and length) on OCT images, and ...

      Read Full Article
    6. Heartbeat OCT and Motion-Free 3D In Vivo Coronary Artery Microscopy

      Heartbeat OCT and Motion-Free 3D In Vivo Coronary Artery Microscopy

      Intravascular optical coherence tomography (IV-OCT) has gained widespread use over the past few years, offering highly detailed images of coronary artery pathologies and interventions (1) . In contrast to the cross-sectional view, longitudinal sections and 3-dimensional (3D) renderings are affected by cardiac motion artifacts and undersampling, complicating interpretation and measurements (2) . We developed Heartbeat OCT, a new OCT method that achieves up to 4,000 frames/s imaging speed for isotropically sampled volume datasets acquired within the diastolic phase of 1 cardiac cycle to restore 3D IV-OCT image fidelity. In this research letter, we present the first in vivo data acquired ...

      Read Full Article
    7. Hybrid intravascular imaging: recent advances, technical considerations, and current applications in the study of plaque pathophysiology

      Hybrid intravascular imaging: recent advances, technical considerations, and current applications in the study of plaque pathophysiology

      Cumulative evidence from histology-based studies demonstrate that the currently available intravascular imaging techniques have fundamental limitations that do not allow complete and detailed evaluation of plaque morphology and pathobiology, limiting the ability to accurately identify high-risk plaques. To overcome these drawbacks, new efforts are developing for data fusion methodologies and the design of hybrid, dual-probe catheters to enable accurate assessment of plaque characteristics, and reliable identification of high-risk lesions. Today several dual-probe catheters have been introduced including combined near infrared spectroscopy-intravascular ultrasound (NIRS-IVUS), that is already commercially available, IVUS-optical coherence tomography (OCT), the OCT-NIRS, the OCT-near infrared fluorescence (NIRF) molecular ...

      Read Full Article
    8. Feature Of The Week 12/06/2015: Heartbeat Optical Coherence Tomography

      Feature Of The Week 12/06/2015: Heartbeat Optical Coherence Tomography

      Intravascular optical coherence tomography (IV-OCT) has gained widespread use over the past few years, offering highly detailed images of the coronary artery pathologies and interventions. In contrast to the cross-sectional view, longitudinal sections and three-dimensional (3D) renderings are affected by cardiac motion artifacts and undersampling, complicating interpretation and measurements. We developed Heartbeat OCT, a new OCT method that overcomes these issues. This study aims to demonstrate in vivo Heartbeat OCT in a preclinical setting, imaging eliminating cardiac motion artifacts, undersampling and non-uniform rotational distortion, to generate high-quality OCT volumes. Using a micro motor actuated catheter and a MHz sweep rate ...

      Read Full Article
    9. A Micromotor Catheter for Intravascular Optical Coherence Tomography

      A Micromotor Catheter for Intravascular Optical Coherence Tomography

      We have developed a new form of intravascular optical coherence tomography (IV-OCT) that allows the extremely fast acquisition of high-resolution images of the coronary arteries. This process leads to much better image quality by eliminating cardiac motion artefacts and undersampling. It relies on a catheter that incorporates a synchronous micromotor with a diameter of 1.0 mm and a rotational speed of up to 5600 revolutions per second, enabling an IV-OCT frame rate of 5.6 kHz. This speed is matched by a wavelength-swept laser that generates up to 2.8 million image lines per second. With this setup, our ...

      Read Full Article
    10. Mapping Intravascular Ultrasound Controversies in Interventional Cardiology Practice

      Mapping Intravascular Ultrasound Controversies in Interventional Cardiology Practice

      Intravascular ultrasound is a catheter-based imaging modality that was developed to investigate the condition of coronary arteries and assess the vulnerability of coronary atherosclerotic plaques in particular. Since its introduction in the clinic 20 years ago, use of intravascular ultrasound innovation has been relatively limited. Intravascular ultrasound remains a niche technology; its clinical practice did not vastly expand, except in Japan, where intravascular ultrasound is an appraised tool for guiding percutaneous coronary interventions. In this qualitative research study, we follow scholarship on the sociology of innovation in exploring both the current adoption practices and perspectives on the future of intravascular ...

      Read Full Article
    11. Effect of temperature and fixation on the optical properties of atherosclerotic tissue: a validation study of an ex-vivo whole heart cadaveric model

      Effect of temperature and fixation on the optical properties of atherosclerotic tissue: a validation study of an ex-vivo whole heart cadaveric model

      Atherosclerotic plaque composition can be imaged using the optical attenuation coefficient derived from intravascular optical coherence tomography (OCT) data. The relation between optical properties and tissue type has been established on autopsy tissues. In this study, we validate an ex-vivo model for the effect of temperature and tissue fixation on optical parameters. We studied the optical attenuation of human coronary arteries at three temperatures, before and after formalin fixation. We developed an en-face longitudinal display of attenuation data of the OCT pullbacks. Using the unfixed, body-temperature condition image as a standard, and after extensive registration with other condition images, we ...

      Read Full Article
    12. Quantitative optical coherence tomography tissue-type imaging for lipid-core plaque detection

      Quantitative optical coherence tomography tissue-type imaging for lipid-core plaque detection

      Comparison Between OCT Attenuation Imaging and NIRS for 3 Sites (A) NIRS/IVUS images; (B) OCT and (C) Attenuation coefficient analyzed from the OCT data (color coded 0–12 mm-1). Scale bars are 1 mm. Site 1 (refer to Fig. 1 ): a mixed lesion contains calcifications (bright echos on IVUS with dorsal shadowing; 3–5 o'clock) and lipid-rich tissue (5–10 o'clock). High attenuation (red-orange-yellow) in the plaque (white arrow) coincides with the yellow in the NIRS data. The calcification (marked by c) identified on IVUS and OCT has low attenuation (blue) . Site 2: an eccentric lipid-core plaque ...

      Read Full Article
    13. Feature Of The Week 6/30/13: Ultrafast Intravascular Optical Coherence Tomography Imaging

      Feature Of The Week 6/30/13: Ultrafast Intravascular Optical Coherence Tomography Imaging

      The fastest commercial intravascular optical coherence tomography (OCT) systems acquire 160 frames/second with 500 lines/frame, and the pullback speed is limited to 40 mm∕s. In this situation, the images are under sampled in the pullback direction: Only 12% of the lumen is sampled because the sampling interval of 250 μm is much larger than the transverse resolution, which is approximately 30 μm. In clinical situations, the cardiac motion also affects the OCT acquisition. The pullback procedure for the whole artery takes several seconds. The cardiac motion during acquisition will cause inaccuracy in frame spacing and possibly frame ...

      Read Full Article
    14. Ultrahigh-speed intravascular optical coherence tomography imaging at 3200 frames per second

      Ultrahigh-speed intravascular optical coherence tomography imaging at 3200 frames per second

      We demonstrated intravascular OCT imaging with frame rate up to 3.2 kHz (192,000 rpm scanning). This was achieved by using a custom-built catheter in which the circumferential scanning was actuated by a 1.0 mm diameter synchronous motor. The OCT system was based on a Fourier Domain Mode Locked laser operating at an A-line rate of 1.6 MHz. The diameter of the catheter was 1.1 mm at the tip. Ex vivo images of human coronary artery (~78.4 mm length) were acquired at a pullback speed of 100 mm/s. True 3D volumetric imaging of the ...

      Read Full Article
    15. Intravascular optical coherence tomography imaging at 3200 frames per second

      Intravascular optical coherence tomography imaging at 3200 frames per second

      We demonstrate intravascular optical coherence tomography (OCT) imaging with frame rate up to 3.2 kHz (192,000 rpm scanning). This was achieved by using a custom-built catheter in which the circumferential scanning was actuated by a 1.0 mm diameter synchronous motor. The OCT system, with an imaging depth of 3.7 mm (in air), is based on a Fourier domain mode locked laser operating at an A-line rate of 1.6 MHz. The diameter of the catheter is 1.1 mm at the tip. Ex vivo images of human coronary artery (78.4 mm length) were acquired at ...

      Read Full Article
    16. Numerical analysis of astigmatism correction in gradient refractive index lens based optical coherence tomography catheters

      Numerical analysis of astigmatism correction in gradient refractive index lens based optical coherence tomography catheters

      Endoscopic optical coherence tomography (OCT) catheters comprise a transparent tube to separate the imaging instrument from tissues. This tube acts as a cylindrical lens, introducing astigmatism into the beam. In this report, we quantified this negative effect using optical simulations of OCT catheter devices, and discuss possible compensation strategies. For esophageal imaging, the astigmatism is aggravated by the long working distance. For intracoronary imaging, the beam quality is degraded due to the liquid imaging environment. A nearly circular beam profile can be achieved by a curved focusing optics. We also consider the method of matching refractive indices, and it is ...

      Read Full Article
    17. Frequency domain multiplexing for speckle reduction in optical coherence tomography

      Frequency domain multiplexing for speckle reduction in optical coherence tomography

      Quantitative analysis of optical coherence tomography data can be strongly hampered by speckle. Here, we introduce a new method to reduce speckle, which leverages from Fourier-domain configurations and operates on individual axial scans. By subdividing the digitized spectrum into a number of distinct narrower windows, each with a different center frequency, several independent speckle patterns result. These can be averaged to yield a lower-resolution image with strongly reduced speckle. The full resolution image remains available for human interpretation; the low resolution version can be used for parametric imaging or quantitative analysis. We demonstrate this technique using intravascular optical frequency domain ...

      Read Full Article
    18. Consensus Standards for Acquisition, Measurement, and Reporting of Intravascular Optical Coherence Tomography Studies: A Report From the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation

      Consensus Standards for Acquisition, Measurement, and Reporting of Intravascular Optical Coherence Tomography Studies: A Report From the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation

      Objectives: The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the diagnosis and treatment of patients with atherosclerosis, including coronary artery disease.Background: Intravascular optical coherence tomography (IVOCT) is a catheter-based modality that acquires images at a resolution of 10 μm, enabling visualization of blood vessel wall microstructure in vivo at an unprecedented level of detail. IVOCT devices are now commercially available worldwide, there is an active user base, and ...

      Read Full Article
    19. Wavelength multiplexing for FD-OCT speckle averaging

      Wavelength multiplexing for FD-OCT speckle averaging

      Quantitative analysis of OCT data can be strongly hampered by speckle. We propose a new method to reduce speckle, operating on a single Fourier-domain optical coherence tomography (FD-OCT) A-line. The full acquired spectrum is used for image generation, exhibiting fully developed speckle. By subdividing the same acquired spectrum in a number of distinct narrower windows, each with a different center frequency, several independent speckles can be generated. These can be averaged to yield a lower-resolution image with strongly reduced speckle. The full resolution image remains available for human interpretation; the low resolution version can be used for parametric imaging. We ...

      Read Full Article
    1-19 of 19
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (19 articles) Anton F. W. van der Steen
    2. (18 articles) Gijs van Soest
    3. (16 articles) Erasmus University
    4. (10 articles) Tianshi Wang
    5. (9 articles) Evelyn Regar
    6. (8 articles) Robert A. Huber
    7. (7 articles) Delft University of Technology
    8. (7 articles) Tom Pfeiffer
    9. (7 articles) Wolfgang Wieser
    10. (6 articles) Massachusetts General Hospital
  3. Popular Articles

  4. Picture Gallery

    Wavelength multiplexing for FD-OCT speckle averaging Consensus Standards for Acquisition, Measurement, and Reporting of Intravascular Optical Coherence Tomography Studies: A Report From the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation Frequency domain multiplexing for speckle reduction in optical coherence tomography Numerical analysis of astigmatism correction in gradient refractive index lens based optical coherence tomography catheters Intravascular optical coherence tomography imaging at 3200 frames per second Ultrahigh-speed intravascular optical coherence tomography imaging at 3200 frames per second Feature Of The Week 6/30/13: Ultrafast Intravascular Optical Coherence Tomography Imaging A Micromotor Catheter for Intravascular Optical Coherence Tomography Feature Of The Week 12/06/2015: Heartbeat Optical Coherence Tomography Feature Of The Week 09/10/2017: Thermo-elastic  Optical Coherence Tomography Postdoctoral Associate Position at Duke Vision and Image Processing Laborator Anterior segment optical coherence tomography angiography