1. Articles from Marco Bonesi

    1-15 of 15
    1. Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography

      Comprehensive vascular imaging using optical coherence tomography-based angiography and photoacoustic tomography

      Studies have proven the relationship between cutaneous vasculature abnormalities and dermatological disorders, but to image vasculature noninvasively in vivo , advanced optical imaging techniques are required. In this study, we imaged a palm of a healthy volunteer and three subjects with cutaneous abnormalities with photoacoustic tomography (PAT) and optical coherence tomography with angiography extension (OCTA). Capillaries in the papillary dermis that are too small to be discerned with PAT are visualized with OCTA. From our results, we speculate that the PA signal from the palm is mostly from hemoglobin in capillaries rather than melanin, knowing that melanin concentration in volar skin ...

      Read Full Article
    2. Dove prism based rotating dual beam bidirectional Doppler OCT

      Dove prism based rotating dual beam bidirectional Doppler OCT

      Traditional Doppler OCT is highly sensitive to motion artifacts due to the dependence on the Doppler angle. This limits its accuracy in clinical practice. To overcome this limitation, we use a bidirectional dual beam technique equipped with a novel rotating scanning scheme employing a Dove prism. The volume is probed from two distinct illumination directions with variable controlled incidence plane, allowing for reconstruction of the true flow velocity at arbitrary vessel orientations. The principle is implemented with Swept Source OCT at 1060nm with 100,000 A-Scans/s. We apply the system to resolve pulsatile retinal absolute blood velocity by performing ...

      Read Full Article
    3. Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser

      Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser

      We present a novel, high-speed, polarization-sensitive, optical coherence tomography set-up for retinal imaging operating at a central wavelength of 1060 nm which was tested for in vivo imaging in healthy human volunteers. We use the system in combination with a Fourier domain mode locked laser with active spectral shaping which enables the use of forward and backward sweep in order to double the imaging speed without a buffering stage. With this approach and with a custom designed data acquisition system, we show polarization-sensitive imaging with an A-scan rate of 350 kHz. The acquired three-dimensional data sets of healthy human volunteers ...

      Read Full Article
    4. High-speed polarization sensitive optical coherence tomography scan engine based on Fourier domain mode locked laser

      High-speed polarization sensitive optical coherence tomography scan engine based on Fourier domain mode locked laser

      We report on a new swept source polarization sensitive optical coherence tomography scan engine that is based on polarization maintaining (PM) fiber technology. The light source is a Fourier domain mode locked laser with a PM cavity that operates in the 1300 nm wavelength regime. It is equipped with a PM buffer stage that doubles the fundamental sweep frequency of 54.5 kHz. The fiberization allows coupling of the scan engine to different delivery probes. In a first demonstration, we use the system for imaging human skin at an A-scan rate of 109 kHz. The system illuminates the sample with ...

      Read Full Article
    5. High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source

      High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source

      Optical coherence tomography (OCT) in the 1060nm range is interesting for in vivo imaging of the human posterior eye segment (retina, choroid, sclera), as it permits a long penetration depth. Complementary to structural images, polarization-sensitive OCT (PS-OCT) images visualize birefringent, polarization-maintaining or depolarizing areas within the sample. This information can be used to distinguish retinal layers and structures with different polarization properties. High imaging speed is crucial for imaging ocular structures in vivo in order to minimize motion artifacts while acquiring sufficiently large datasets. Here, we demonstrate PS-OCT imaging at 350 kHz A-scan rate using a two-channel PS-OCT system in ...

      Read Full Article
    6. Feature Of The Week 4/29/12: Medical University of Vienna Demonstrates Automated Measurement of Choroidal Thickness in the Human Eye by PS-OCT

      Feature Of The Week 4/29/12: Medical University of Vienna Demonstrates Automated Measurement of Choroidal Thickness in the Human Eye by PS-OCT

      Researchers at the Medical University of Vienna have a long history of outstanding contributions to the field of Optical Coherence Tomography dating back 25 years.  This week work by Dr. Hitzenberger, one of the pioneers of the field, and his colleagues is featured demonstrating automated measurement of choroidal thickness in the human eye by polarization sensitive optical coherence tomography. Below is a summary of their work.Imaging of retinal layers and quantitative measurements of their thickness are among the most important applications of OCT. E.g., the total retinal thickness is an important quantity for diagnosis of diabetic retinopathy, the ...

      Read Full Article
    7. High-Speed Retinal Imaging with Polarization-Sensitive OCT at 1040 nm

      High-Speed Retinal Imaging with Polarization-Sensitive OCT at 1040 nm

      Purpose. To demonstrate the ability of a new high-speed polarization-sensitive optical coherence tomography (PS-OCT) system for retinal imaging at 1040 nm. Methods. A new polarization-sensitive swept source OCT system in the 1 [mu]m wavelength range is used to image the retina of healthy volunteers. The instrument is operated at an A-scan rate of 100 kHz which is about three times faster than previously reported PS-OCT instruments in this wavelength region. The increased imaging speed can be used to record densely sampled volumes of the retina. Moreover, it enables averaging of several B-scans recorded at the same location to obtain ...

      Read Full Article
    8. Automated measurement of choroidal thickness in the human eye by polarization sensitive optical coherence tomography

      Automated measurement of choroidal thickness in the human eye by polarization sensitive optical coherence tomography

      We present a new method to automatically segment the thickness of the choroid in the human eye by polarization sensitive optical coherence tomography (PS-OCT). A swept source PS-OCT instrument operating at a center wavelength of 1040 nm is used. The segmentation method is based entirely on intrinsic, tissue specific polarization contrast mechanisms. In a first step, the anterior boundary of the choroid, the retinal pigment epithelium, is segmented based on depolarization. In a second step, the choroid-sclera interface is found by using the birefringence of the sclera. The method is demonstrated in five healthy eyes. The mean repeatability (standard deviation ...

      Read Full Article
    9. Visualization of microvasculature by dual-beam phase-resolved Doppler optical coherence tomography

      Visualization of microvasculature by dual-beam phase-resolved Doppler optical coherence tomography

      We present a dual-beam Doppler optical coherence tomography system for visualizing the microvasculature within the retina. The sample arm beams from two identical spectral domain optical coherence tomography (SD-OCT) systems are combined such that there is a small horizontal offset between them at the retina. Thereby we record two tomograms which are slightly separated in time. Phase-resolved Doppler analysis is performed between these two data sets. This system allows blood capillary imaging with high flow sensitivity and variable velocity range. To demonstrate the performance of our system we present images of the microvascular network around the fovea and around the ...

      Read Full Article
    10. Sample motion-insensitive, full-range, complex, spectral-domain optical-coherence tomography

      Sample motion-insensitive, full-range, complex, spectral-domain optical-coherence tomography

      We present a full-range, complex, spectral-domain optical-coherence-tomography (SD-OCT) system that is based on a double-beam scanning approach. The sample beams of two identical SD-OCT setups are combined collinearly by a bulk optic beam splitter before illuminating the object. The required phase shift for the complex signal reconstruction comes from the phase difference between both interferometers. Because of the double-beam scanning approach, our system is completely insensitive to sample motion. To demonstrate the performance of our setup, we present images of the human optic nerve head in vivo and of a human tooth.

      Read Full Article
    11. Quantum Dot Superluminescent Diodes for Optical Coherence Tomography: Device Engineering

      Quantum Dot Superluminescent Diodes for Optical Coherence Tomography: Device Engineering

      We present a 18 mW fiber-coupled single-mode superluminescent diode with 85 nm bandwidth for application in optical coherence tomography (OCT). First, we describe the effect of quantum dot (QD) growth temperature on optical spectrum and gain, highlighting the need for the optimization of epitaxy for broadband applications. Then, by incorporating this improved material into a multicontact device, we show how bandwidth and power can be controlled. We then go on to show how the spectral shape influences the autocorrelation function, which exhibits a coherence length of <11 $mu$m, and relative noise is found to be 10 dB lower than that of a thermal source. Finally, we apply the optimum device to OCT of in vivo skin and show the improvement that can be made with higher power, wider bandwidth, and lower noise, respectively.

      Read Full Article
    12. Quantum Dot Superluminescent Diodes for Optical Coherence Tomography: Skin Imaging

      Quantum Dot Superluminescent Diodes for Optical Coherence Tomography: Skin Imaging

      We present a high-power (18 mW continuous wave exiting a single-mode fiber and 35 mW exiting the facet), broadband (85 nm full-width at half-maximum) quantum dot-based superluminescent diode, and apply it to a time-domain optical coherence tomography (OCT) setup. First, we test its performance with increasing optical feedback. Then we demonstrate its imaging properties on tissue-engineered (TE) skin and in vivo skin. OCT allows the tracking of epidermal development in TE skin, while the higher power source allows better sensitivity and depth penetration for imaging of in vivo skin layers.

      Read Full Article
    13. Using swept-source optical coherence tomography to monitor the formation of neo-epidermis in tissue-engineered skin

      Using swept-source optical coherence tomography to monitor the formation of neo-epidermis in tissue-engineered skin

      There is an increasing need for a robust, simple to use, non-invasive imaging technology to follow tissue-engineered constructs as they develop. Our aim was to evaluate the use of swept-source optical coherence tomography (SS-OCT) to image tissue-engineered skin as it developed over several weeks. Tissue-engineered skin was produced using both de-epithelialized acellular dermis (DED) and amorphous collagen gels. In both cases the epidermis could be readily distinguished from the neodermis, based on a comparison with standard destructive histology of samples. Constructs produced with DED showed more epidermal/dermal maturation than those produced using collagen. The development of tissue-engineered skin based ...

      Read Full Article
    14. Application of Doppler Optical Coherence Tomography in rheological studies: Blood flow and vessels mechanical properties evaluation

      Doppler Optical Coherence Tomography (DOCT) is a noninvasive optical diagnostic technique, which is well suited for the quantitative mapping of microflow velocity profiles and the analysis of flow-vessel interactions. The noninvasive imaging and quantitative analysis of blood flow in the complex-structured vascular bed is required in many biomedical applications, including those where the determination of mechanical properties of vessels or the knowledge of the mechanic interactions between the flow and the housing medium plays a key role. The change of microvessel wall elasticity could be a potential indicator of cardiovascular disease at the very early stage, whilst monitoring the blood ...

      Read Full Article
    15. Determination of 3D optic axis orientation in cartilage by polarization-sensitive optical coherence tomography

      Nadya Ugryumova, Marco Bonesi, and Stephen J. Matcher Polarization-sensitive optical coherence tomography has been used to solve fast-axis fibre orientation in three dimension space. Previously we have demonstrated that the apparent variations in polar angle orientation of collagen fibers along sagittal ridge of equine third metacarpophalangeal joint e ... [Proc. SPIE Int. Soc. Opt. Eng. 6858, 68580I (2008)] published Wed Feb 6, 2008.

      Read Full Article
    1-15 of 15
  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. (14 articles) Marco Bonesi
    2. (12 articles) Medical University of Vienna
    3. (8 articles) Michael Pircher
    4. (8 articles) Teresa Torzicky
    5. (8 articles) Christoph K. Hitzenberger
    6. (8 articles) Erich Götzinger
    7. (7 articles) Stefan Zotter
    8. (5 articles) Steven J. Matcher
    9. (4 articles) University of Sheffield
    10. (3 articles) Robert A. Huber
  3. Popular Articles

  4. Picture Gallery

    Using swept-source optical coherence tomography to monitor the formation of neo-epidermis in tissue-engineered skin Quantum Dot Superluminescent Diodes for Optical Coherence Tomography: Skin Imaging Quantum Dot Superluminescent Diodes for Optical Coherence Tomography: Device Engineering Sample motion-insensitive, full-range, complex, spectral-domain optical-coherence tomography Visualization of microvasculature by dual-beam phase-resolved Doppler optical coherence tomography Automated measurement of choroidal thickness in the human eye by polarization sensitive optical coherence tomography High-Speed Retinal Imaging with Polarization-Sensitive OCT at 1040 nm Feature Of The Week 4/29/12: Medical University of Vienna Demonstrates Automated Measurement of Choroidal Thickness in the Human Eye by PS-OCT High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source Intravitreal Ranibizumab Monotherapy or Combined with Laser for Diabetic Macular Edema (OCT guided study) Prospective evaluation of drug eluting self‐apposing stent for the treatment of unprotected left main coronary artery disease: 1‐year results of the TRUNC study Clinical validation of the RTVue optical coherence tomography angiography image quality indicators