1. Articles from Tapio Fabritius

    1-14 of 14
    1. Effect of solvent lamination on roll-to-roll hot-embossed PMMA microchannels evaluated by optical coherence tomography

      Effect of solvent lamination on roll-to-roll hot-embossed PMMA microchannels evaluated by optical coherence tomography

      Manufacturing of microfluidic based diagnostic devices requires small tolerances and uniform quality to guarantee reliable and repeatable test results. This work describes characterization of morphological changes that occur to a hot embossed PMMA microfluidic channel after solvent lamination with a PMMA lid. A non-contact cross-sectional analysis of the lidded microfluidic device was performed by optical coherence tomography (OCT). The solvent induced morphology change led to a porous structure in bottom corners of hot-embossed channels, which allowed a fluid to absorb in the material. The measurements of solvent diffusion showed faster diffusion rate at the corners of the channel, in which ...

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    2. Quantification of cell-free layer thickness and cell distribution of blood by optical coherence tomography

      Quantification of cell-free layer thickness and cell distribution of blood by optical coherence tomography

      A high-speed optical coherence tomography (OCT) with 1 - μ m axial resolution was applied to assess the thickness of a cell-free layer (CFL) and a spatial distribution of red blood cells (RBC) next to the microchannel wall. The experiments were performed in vitro in a plain glass microchannel with a width of 2 mm and height of 0.2 mm. RBCs were suspended in phosphate buffered saline solution at the hematocrit level of 45%. Flow rates of 0.1 to 0.5    ml / h were used to compensate gravity induced CFL. The results indicate that OCT can be efficiently used for ...

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    3. Choroidal thickness measurement in healthy Japanese subjects by three-dimensional high-penetration optical coherence tomography

      Choroidal thickness measurement in healthy Japanese subjects by three-dimensional high-penetration optical coherence tomography

      Background We performed retinal and choroidal thickness mapping by three-dimensional high-penetration optical coherence tomography (OCT) and evaluated the choroidal thickness distribution throughout the macula in healthy eyes. Methods Forty-three eyes of 43 healthy Japanese volunteers were evaluated by 1060-nm swept-source OCT. The eyes were scanned with a three-dimensional raster scanning protocol, and the mean retinal and choroidal thicknesses of the posterior sectors were obtained. The sectors were defined by the Early Treatment Diabetic Study (ETDRS) layout. These data were compared by age (23–56 years), spherical equivalent refractive error (between +0.9 D and −10.3 D), and axial length ...

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    4. Fast retinal layer identification for optical coherence tomography images

      Fast retinal layer identification for optical coherence tomography images

      Fast method for identifying the internal limiting membrane (ILM) and retinal pigment epithelium (RPE) from optical coherence tomography images is demonstrated. To avoid unnecessary increment of calculation time, a strong downsampling of the original data set is performed to reduce a number of processed pixels. In ILM segmentation, the obtained data cube is filtered with two different kinds of parameters and two estimates for the position of ILM is determined. A simple smoothness value is determined for both estimates and better estimate is used for future processing. A smaller portion of pixels around estimated ILM are extracted from the down ...

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    5. Wettability characterization method based on optical coherence tomography imaging

      Wettability characterization method based on optical coherence tomography imaging
      A novel method for surface wetting characterization based on contact angle measurements is presented. Three dimensional structural imaging of a droplet on a substrate is performed using optical coherence tomography (OCT) which provides micrometer resolution images without contact with the sample. An automatic OCT intensity variation based, layer segmentation method was implemented to identify air-droplet, droplet-substrate and air-substrate interfaces. A glycerol droplet on a rough tilted glass substrate was used as a test sample to demonstrate the applicability of the proposed method for wetting characterization. Results show that the contact angle of any observation angle can be obtained. In addition ...
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    6. Automated segmentation of the macula by optical coherence tomography

      Automated segmentation of the macula by optical coherence tomography
      This paper presents optical coherence tomography (OCT) signal intensity variation based segmentation algorithms for retinal layer identification. Its main ambition is to reduce the calculation time required by layer identification algorithms. Two algorithms, one for the identification of the internal limiting membrane (ILM) and the other for retinal pigment epithelium (RPE) identification are implemented to evaluate structural features of the retina. Using a 830 nm spectral domain OCT device, this paper demonstrates a segmentation method for the study of healthy and diseased eyes.
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    7. Automated retinal pigment epithelium identification from optical coherence tomography images

      Simple and robust method for identifying the retinal pigment epithelium (RPE) from optical coherence tomography images is demonstrated. At first, the maximum intensity value of each A-scans were determined and the depth position of those pixels are identified. The obtained 2D matrix is used as first ... [Proc. SPIE 7168, 716827 (2009)] published Fri Feb 20, 2009.
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    8. Blood flow imaging at deep posterior human eye using 1 um spectral-domain optical coherence tomography

      Blood flow imaging of deep posterior eye has been demonstrated by using 1-um spectral-domain optical coherence tomography. The high contrast imaging of deep posterior eye, such as the choroid and the sclera, enables blood flow imaging of choroidal vessels and short posterior ciliary arteries. Opt ... [Proc. SPIE 7168, 716808 (2009)] published Thu Feb 19, 2009.
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    9. Automated retinal shadow compensation of optical coherence tomography images

      We present an automated numerical method of compensating for retinal shadows in the choroid. In this method, signal extinction caused by retinal vessels is estimated by subtracting median A-scans obtained from beneath the retinal vessels and A-scans from the surrounding area. Adding the obtained offset vector to A-scans from beneath the retinal vessels allows compensating for shadows in the choroid. In vivo imaging of the human eye was performed by 840-nm-band standard resolution spectral domain optical coherence tomography (SD-OCT), and choroidal vasculature projection images were calculated. Removal of retinal shadows distinctly improved the readability of choroidal images
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    10. Full-range, high-speed, high-resolution 1 mu m spectral-domain optical coherence tomography with BM-scan method for the human posterior eye imaging

      High-speed, high-resolution full-range 1 [mu]m spectral-domain optical coherence tomography has been demonstrated. The axial resolution of 7 [mu]m and the depth range of 2.6 mm in tissue are achieved with the line rate of 46,900 Hz. The sensitivity of 98 dB is obtained with full-range imaging. These ... [Proc. SPIE 7139, 713914 (2008)] published Tue Dec 30, 2008.
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    11. Full-range, high-speed, high-resolution 1μm spectral-domain optical coherence tomography using BM-scan for volumetric imaging of the human posterior eye

      An alternative optical coherence tomography (OCT) to clinical ophthalmic 830 nm spectral-domain OCTs (SD-OCT) is demonstrated. An axial resolution of 7.4 µm, ranging depth of 4.2 mm in tissue, sensitivity of 98.5 dB, and detection speed of 38,300 axial scans/s have been achieved. These are comparable or superior to those of recently commercially available ophthalmic 830 nm SD-OCTs in clinics. In addition, fast volumetric imaging for the in vivo human posterior eye with high-contrast of the choroid is achieved. A broadband 1.04 µm light source enables the high-contrast and high resolution imaging of the ...

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    12. Quantitative retinal-blood flow measurement with three-dimensional vessel geometry determination using ultrahigh-resolution Doppler optical coherence angiography

      Shuichi Makita, Tapio Fabritius, Yoshiaki Yasuno. Retinal blood flow quantification by retinal vessel segmentation with Doppler optical coherence angiography is presented. Vessel diameter, orientation, and position are determined in an en face vessel image and two representative cross-sectional flow images of the vessel. Absolute blood flow ... [Opt. Lett. 33, 836-838 (2008)]
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    13. Retinal blood flow measurement by using optical coherence tomography

      Shuichi Makita, Tapio Fabritius, Masahiro Miura et al. Quantification of the three-dimensional (3D) retinal vessel structure and blood flow is demonstrated. 3D blood flow distribution is obtained by Doppler optical coherence angiography (D-OCA). Vessel parameters, i.e. diameter, orientation, and position, are determined in an en face vessel image. The D ... [Proc. SPIE Int. Soc. Opt. Eng. 6847, 68470J (2008)] published Mon Feb 18, 2008.
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    14. Optical method for liquid sorption measurements in paper (Thesis)

      Optical method for liquid sorption measurements in paper (Thesis)
      This thesis presents an effective optical method for measuring liquid sorption into paper. From the two tested methods, based on a streak-camera and optical coherence tomography (OCT), the last-mentioned proved very promising for investigating dynamical paper-liquid interactions as spatially and temporally dependent processes. The streak-camera measurements were performed to explore the relationship between paper properties and light migration in dry and refractive index matched paper in general. Based on streak-camera measurements, a novel procedure for determining the average refractive index of cellulose fibre tissue was also presented here. In addition, the streak camera method lent itself to paper porosity determination ...
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    1-14 of 14
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  2. Topics in the News

    1. (14 articles) Tapio E. J. Fabritius
    2. (13 articles) University of Oulu
    3. (11 articles) University of Tsukuba
    4. (11 articles) Shuichi Makita
    5. (11 articles) Yoshiaki Yasuno
    6. (6 articles) Risto A. Myllylä
    7. (5 articles) Masahiro Miura
    8. (3 articles) Tokyo Medical University
    9. (2 articles) Janne Lauri
    10. (1 articles) Korea Advanced Institute of Science and Technology
    11. (1 articles) Kawasaki Medical School
    12. (1 articles) Harbin Medical University
    13. (1 articles) Hector M. Garcia-Garcia
    14. (1 articles) Bo Yu
    15. (1 articles) Ron Waksman
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    Automated segmentation of the macula by optical coherence tomography Wettability characterization method based on optical coherence tomography imaging Choroidal thickness measurement in healthy Japanese subjects by three-dimensional high-penetration optical coherence tomography OCT parameters of the optic nerve head and the retina as surrogate markers of brain volume in a normal population, a pilot study Choroidal vessel density in unilateral hyperopic amblyopia using en-face optical coherence tomography Association between food and nutrients intakes and coronary plaque vulnerability in patients with coronary heart disease: An optical coherence tomography study Optical Coherence Tomography based treatment approach for patients with Acute Coronary Syndrome Using OCT Fixation Shift to Assess Eccentric Fixation in Children With Residual Amblyopia Intraretinal microvascular changes after ERM and ILM peeling using SSOCTA Image sensor for spectral-domain optical coherence tomography on a chip Identifying Diabetic Macular Edema and Other Retinal Diseases by Optical Coherence Tomography Image and Multiscale Deep Learning Factors Associated with Changes in Retinal Layers Following Acute Optic Neuritis: A Longitudinal Study Using Optical Coherence Tomography