1. Articles from masato ohmi

    1-21 of 21
    1. Analysis of sweating by optical coherence tomography in patients with palmoplantar hyperhidrosis

      Analysis of sweating by optical coherence tomography in patients with palmoplantar hyperhidrosis

      Optical coherence tomography (OCT) is a high-resolution tomographic imaging technique that uses optical interference. OCT has enabled the non-invasive three-dimensional analysis of individual acrosyringia in the stratum corneum in human skin. However, no report on the measurement of sweating by OCT using clinical data from humans has been published to date. Twenty patients with hyperhidrosis and twenty healthy subjects were included in this study. Imaging of acrosyringia in the stratum corneum using OCT and measurement of the sweat rate using the ventilated capsule method were performed simultaneously. The hand grip exercise of the right hand was used as a load ...

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    2. High frame-rate en face optical coherence tomography system using KTN optical beam deflector

      High frame-rate en face optical coherence tomography system using KTN optical beam deflector

      We developed high frame-rate en face optical coherence tomography (OCT) system using KTa 1-x Nb x O 3 (KTN) optical beam deflector. In the imaging system, the fast scanning was performed at 200 kHz by the KTN optical beam deflector, while the slow scanning was performed at 800 Hz by the galvanometer mirror. As a preliminary experiment, we succeeded in obtaining en face OCT images of human fingerprint with a frame rate of 800 fps. This is the highest frame-rate obtained using time-domain (TD) en face OCT imaging. The 3D-OCT image of sweat gland was also obtained by our imaging ...

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    3. Application to skin physiology using optical coherence tomography

      Application to skin physiology using optical coherence tomography

      Background and aims: The sweat glands and peripheral vessels beneath the skin surface act as minute organs governed by the skin sympathetic nerves and have important physiological functions for body temperature control and nutrition support along with maintenance of a peripheral organization. Dynamics of the mental sweating of sweat glands and the peripheral vessels reflect the activity of a sympathetic nerve. The purpose of this paper is to study the dynamic observation and analysis of sweat glands and a peripheral vessels by optical coherence tomography (OCT). Materials and Methods: In the dynamic analysis of mental sweating of sweat glands, after ...

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      Mentions: Osaka University
    4. Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images

      Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images

      No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography ( μ CT ) for the same sample. The purpose of this study was to clarify both OCT and μ CT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior ...

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      Mentions: Osaka University
    5. Precise measurement of volume of eccrine sweat gland in mental sweating by optical coherence tomography

      Precise measurement of volume of eccrine sweat gland in mental sweating by optical coherence tomography

      We have demonstrated dynamic analysis of the physiological function of eccrine sweat glands underneath skin surface by optical coherence tomography (OCT). In this paper, we propose a method for extraction of the specific eccrine sweat gland by means of the connected component extraction process and the adaptive threshold method, where the en face OCT images are constructed by the swept-source OCT. In the experiment, we demonstrate precise measurement of the volume of the sweat gland in response to the external stimulus.

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      Mentions: Osaka University
    6. Development of novel high-speed en face optical coherence tomography system using KTN optical beamdeflector

      Development of novel high-speed en face optical coherence tomography system using KTN optical beamdeflector

      We developed a novel high-speed en face optical coherence tomography (OCT) system using a KTa 1– x Nb x O 3 (KTN) optical beam deflector. Using the imaging system, fast scanning was performed at 200 kHz by the KTN beam deflector, while slow scanning was performed at 400 Hz by the galvanometer mirror. In a preliminary experiment, we obtained en face OCT images of a human fingerprint at 400 fps. This is the highest speed reported in time-domain en face OCT imaging and is comparable to the speed of swept-source OCT. A 3D-OCT image of a sweat gland was also ...

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    7. Nondestructive observation of teeth post core space using optical coherence tomography: a pilot study

      Nondestructive observation of teeth post core space using optical coherence tomography: a pilot study

      Coronal tooth lesions, such as caries, enamel cracking, and composite resin restoration cavities, have been observed by optical coherence tomography (OCT). This pilot study was performed to verify whether OCT could reveal details of root canals filled with resin core build-up. A dual-cure, one-step, self-etch adhesive system-bonding agent (Clearfil Bond SE ONE, Kuraray Noritake Dental) and dual-cure resin composite core material (Clearfil DC Core Automix ONE, Kuraray Noritake Dental) were used according to the manufacturer’s instructions in root canals. OCT was performed at three stages of the core build-up: after the post space preparation, after bonding application, and after ...

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      Mentions: Osaka University
    8. Dynamic Analysis of Mental Sweating by the Time-Sequential Piled-Up En-Face OCT Images

      Dynamic Analysis of Mental Sweating by the Time-Sequential Piled-Up En-Face OCT Images

      In this paper, the dynamic analysis of mental sweating for sound stimulus of a few tens of eccrine sweat glands is per- formed by the time-sequential piled-up en-face optical coherence tomography (OCT) images with the frame spacing of 3.3 sec. In the experiment, the amount of excess sweat can be evaluated simultaneously for a few tens of sweat glands by piling up of all the en-face OCT images. Strong non-uniformity is observed in mental sweating where the amount of sweat in response to sound stimulus is different for each sweat gland. Furthermore, the amount of sweat is significantly increased ...

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      Mentions: Osaka University
    9. High-Speed Optical Coherence Tomography System Using a 200-kHz Swept Light Source with a KTN Deflector

      High-Speed Optical Coherence Tomography System Using a 200-kHz Swept Light Source with a KTN Deflector

      We demonstrate a high-speed swept-source optical coherence tomography (SS-OCT) system, which is based on a high- speed swept light source and a Mach-Zehnder interferometer with a high-speed photodetector. The light source is an external-cavity laser tuned by a KTN electro-optic deflector, which exhibits a very fast response and large deflection. The scanning wavelength range is almost 80 nm up to 200 kHz with a ±400-V deflector driving voltage. The system acquires 1 mm × 1 mm images consisting of 200 × 200 pixels within few milliseconds. We present preliminary SS-OCT images of an in-vitro human nail and an in-vivo finger pad.

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    10. Dynamic imaging of a small artery underneath skin surface of a human finger by optical coherence tomography

      Dynamic imaging of a small artery underneath skin surface of a human finger by optical coherence tomography

      OCT is a powerful tool for detection of physiological functions of micro organs underneath the human skin surface, besides the clinical application to ophthalmology, as recently demonstrated by the authors’ group. In particular, dynamics of peripheral vessels can be observed clearly in the time-sequential OCT images. Among the vascular system, only the small artery has two physiological functions both for the elastic artery and for muscle-controlled one. It, therefore, is important for dynamic analysis of blood flow and circulation. In the time-sequential OCT images obtained with 25 frames/sec, it is found that the small artery makes a sharp ...

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      Mentions: Osaka University
    11. Dynamic analysis for mental sweating of a group of eccrin sweat glands on a human fingertip by optical coherence tomography

      Dynamic analysis for mental sweating of a group of eccrin sweat glands on a human fingertip by optical coherence tomography
      OCT is highly potential for in vivo observation of human sweating dynamics which affects activity of the sympathetic nerve. In this paper, we demonstrate dynamic OCT analysis of mental sweating of a group of eccrin sweat glands. The sweating dynamics is tracked simultaneously for nineteen sweat glands by time-sequential piled-up en-face OCT images with the frame spacing of 3.3 sec. Strong non-uniformity is observed in mental sweating where the amount of excess sweat is different for each sweat gland although the sweat glands are adjacent to each other. The non-uniformity should be necessary to adjust as precisely the total ...
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      Mentions: Osaka University
    12. Dynamic analysis of a small artery of a human finger by optical coherence tomography

      Dynamic analysis of a small artery of a human finger by optical coherence tomography

      OCT is highly potential for development of a new field of dynamic skin physiology, as recently reported by the authors. In this paper, we demonstrate dynamic analysis of a small artery of a human finger by the SS-OCT. Among the vascular system, only the small artery has two physiological functions both for the elastic artery (like main and middle arteries) and for muscle-controlled one (like arterioles). It, therefore, is important for dynamic analysis of blood flow and circulation. In the time-sequential OCT images obtained with 25 frames/s, it is found that the small artery makes a sharp response to ...

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      Mentions: Osaka University
    13. Real-time OCT imaging of laser ablation of biological tissue

      Real-time OCT imaging of laser ablation of biological tissue
      During laser ablation of a diseased area, the surrounding tissues and organs suffer serious damage. In order to optimize laser ablation of biological tissues, it is necessary to observe the laser ablation in situ. The real-time imaging of tissue laser ablation is realized in the fusion system of the YAG ablation laser and optical coherence tomography (OCT). A swept-source OCT (SS-OCT) is combined with a YAG-laser ablation system. In this paper, we demonstrate real-time OCT imaging of tissue laser ablation. The fiber-optic swept source OCT (SS-OCT) with 25 frames / s is used for the in situ observation where tissue laser ...
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      Mentions: Osaka University
    14. Dynamic analysis of mental sweating by optical coherence tomography

      Dynamic analysis of mental sweating by optical coherence tomography
      In the dynamic OCT of mental sweating, we have found internal mental sweating without ejection of excess sweat from the spiral lumen to the skin surface. Internal sweating occurs more often in the case where mental stress is applied to a volunteer, and it is more useful for evaluation of activity of the sympathetic nerve. Furthermore, the MIP imaging has been proposed for quick 3-D imaging of the spiral lumen of sweat glands. Using time-sequential MIP images with the frame spacing as short as 1.4 sec, several sweat glands can be tracked simultaneously to quantify sweating stimulated by a ...
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      Mentions: Osaka University
    15. Progress of OCT and its applications

      Optical coherence tomography (OCT) is the cross-sectional imaging of biological tissue based on the low-coherence interferometry, where the image resolution is around 10 m with the imaging depth of 1 to 2 mm. Since its first demonstration, OCT has been developed intensively for clinical diagnoses of ophthalmology and arteriosclerosis. Beside the clinical applications, OCT is used for analysis of physiological functions underneath the human skin surface. Recently, we proposed and demonstrated the dynamic OCT for in vivo observation of physiological functions of small organs underneath the skin surface. In the dynamic OCT, tomographic images are obtained time-sequentially for tracking of ...
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      Mentions: Osaka University
    16. Maximum intensity projection imaging for dynamic analysis of mental sweating by optical coherence tomography

      A novel 3-D image construction method with maximum intensity projection (MIP) of B-mode OCT images is proposed for in vivo dynamic analysis of mental sweating on human fingertips. Time-sequential MIP-OCT images with the frame spacing as short as 1.4 sec provide us quantitative analysis of the sweati ... [Proc. SPIE 7168, 71682D (2009)] published Fri Feb 20, 2009.
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      Mentions: Osaka University
    17. Dynamic analysis of laser ablation of biological tissue using a real-time OCT

      In laser ablation of biological tissues, tomography of the tissue surface is necessary for measurement of the crater depth and observation of the thermal damage of the tissue. Optical coherence tomography (OCT) is a very promising candidate for an in-situ observation of the tissue. We demonstrate here dynamic analysis of tissue laser ablation using a real-time OCT.
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      Mentions: Osaka University
    18. Dynamic analysis of internal and external mental sweating by optical coherence tomography

      Mental sweating is human sweating that is accelerated via the sympathetic nerve by application of mental or physical stress. In the neurosciences, there is keen interest in this type of sweating, because the amount of sweat in response to a stress applied to a volunteer directly reflects activity of the sympathetic nerve. It is therefore of particular value that optical coherence tomography (OCT) can provide clear in vivo imaging of the spiral lumen of an eccrin sweat gland in the epidermis with a spatial resolution around 10 ┬Ám. We demonstrate dynamic OCT of mental sweating of an eccrin sweat gland ...
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      Mentions: Osaka University
    19. Maximum-Intensity-Projection Imaging for Dynamic Analysis of Mental Sweating by Optical Coherence Tomography

      Authors: Hiroyuki Saigusa, Yoshihiro Ueda, Akihiro Yamada, Masato Ohmi, Makoto Ohnishi, Mitsuo Kuwabara, and Masamitsu HarunaOptical coherence tomography (OCT) shows great potential for microscopic observation of human sweating dynamics. It should be a key technology in the development of new techniques for the study of dynamic physiology. In this study, the dynamic motion of eccrin sweat glands is visualized by three-dimensional (3-D) OCT imaging, and a novel 3-D image construction method, using maximum intensity projection (MIP) of B-mode OCT images, is proposed for in vivo dynamic analysis of mental sweating on human fingertips. Time-sequential MIP-OCT images with a frame spacing ...
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      Mentions: Osaka University
    20. Maximum-intensity-projection images for dynamic analysis of mental sweating by optical coherence tomography

      Hiroyuki Saigusa, Yoshihiro Ueda, Akihiro Yamada et al. We demonstrate a novel 3-D image construction method with maximum intensity projection (MIP) of B-mode images obtained by the swept-source OCT. The time-sequential MIP images with a frame spacing of only 0.7 sec are obtained to make dynamic analysis of mental sweating on human fingertips. ... [Proc. SPIE 7004, 70040V (2008)] published Fri May 16, 2008.
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      Mentions: Osaka University
    1-21 of 21
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