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  • 1
    Online Resource
    Online Resource
    Doppler Signal Processing of Blood Flow Using a Wavelet Transform
    IOP Publishing ; 1996
    In:  Japanese Journal of Applied Physics Vol. 35, No. 5S ( 1996-05-01), p. 3131-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 35, No. 5S ( 1996-05-01), p. 3131-
    Abstract: In medical echography, Doppler signal analysis is one of the most important diagnostic techniques. In Doppler signal analysis, time-frequency localization techniques are necessary. Many techniques have been proposed for the analysis. Short-time Fourier transform (STFT) is one of the most popular techniques. STFT has a fixed time-frequency window making it inappropriate for analysis of signals having a wide bandwidth. On the other hand, recently, wavelet transform (WT) has received much attention. WT has a flexible time-frequency window adaptable to any time-frequency range. In this paper, we describe an application of STFT and WT to Doppler signal processing. The STFT in this study had a rectangular window and required fast Fourier transform (FFT). On the other hand, the WT with the Morlet function as the mother wavelet was modified to reduce the amount of calculation. Then, we compared the suitability of STFT and WT for application to Doppler signal processing of a simulation and an actual blood flow. In the simulation, a flow having fast and slow velocity changes was assumed. The simulation revealed that the WT could reproduce the fast change of flow velocity, while the STFT could not. Then, a blood flow Doppler signal was measured at a point near the mitral valve in the left ventriculus. Only the WT was capable of reproducing the fast change of flow velocity in the heart. The WT is expected to be useful for analyzing blood flow disorders such as regurgitation.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.35.3131
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 1996
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
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    Online Resource
  • 2
    Online Resource
    Online Resource
    Visualization of Blood Flow with Two-Dimensional Moving Target Indication
    IOP Publishing ; 1995
    In:  Japanese Journal of Applied Physics Vol. 34, No. 9R ( 1995-09-01), p. 5006-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 34, No. 9R ( 1995-09-01), p. 5006-
    Abstract: Based on high-frame-rate digital subtraction echography (HFDSE), we developed a new imaging method to visualize blood flow, i.e., two-dimensional moving target indication (2D-MTI). This method reveals blood flow on a plane by extracting a moving target in the blood flow from ultrasonic B-mode images and tracking it on successive images. Experiments were performed using a model flow path. The results show that particles were extracted from ultrasonic B-mode images, and flow was visualized.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.34.5006
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 1995
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
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    Online Resource
  • 3
    Online Resource
    Online Resource
    Visualization and Analysis of Myocardial Transition by Cardiac Ultrasound Images
    IOP Publishing ; 1995
    In:  Japanese Journal of Applied Physics Vol. 34, No. 5S ( 1995-05-01), p. 2844-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 34, No. 5S ( 1995-05-01), p. 2844-
    Abstract: In this paper we present a technique for visualization and analysis of cardiac wall motion, i.e., myocardial transition abnormalities, by digital cardiac ultrasound B-mode images. This technique is based on the correspondence analysis of characteristic points, called landmarks, extracted from endocardial boundary locations and can be used for wall motion analysis of the heart. The algorithm for this technique is that first, cardiac images are segmented into the myocardium and the background image using the gradient relaxation method and endocardial boundary locations are extracted. Next, the landmarks with geometric features are specified, and correspondence analysis is performed with landmarks of the next image. Functional diagnosis of moving organs can be performed by classifying the endocardial boundary into some appropriate colors and superimposing on the original B-mode image.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.34.2844
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 1995
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
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    Online Resource
  • 4
    Online Resource
    Online Resource
    3D Dynamic Echocardiography with a Digitizer
    IOP Publishing ; 1998
    In:  Japanese Journal of Applied Physics Vol. 37, No. 5S ( 1998-05-01), p. 3097-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 37, No. 5S ( 1998-05-01), p. 3097-
    Abstract: In this paper, a three-dimensional (3D) dynamic ultrasound (US) imaging system, where a US brightness-mode (B-mode) image triggered with an R-wave of electrocardiogram (ECG) was obtained with an ultrasound diagnostic device and the location and orientation of the US probe were simultaneously measured with a 3D digitizer, is described. The obtained B-mode image was then projected onto a virtual 3D space with the proposed interpolation algorithm using a Gaussian operator. Furthermore, a 3D image was presented on a cathode ray tube (CRT) and stored in virtual reality modeling language (VRML). We performed an experiment to reconstruct a 3D heart image in systole using this system. The experimental results indicate that the system enables the visualization of the 3D and internal structure of a heart viewed from any angle and has potential for use in dynamic imaging, intraoperative ultrasonography and tele-medicine.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.37.3097
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 1998
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
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  • 5
    Online Resource
    Online Resource
    Dynamic Three-Dimensional Echocardiography
    IOP Publishing ; 2000
    In:  Japanese Journal of Applied Physics Vol. 39, No. 8R ( 2000-08-01), p. 5028-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 39, No. 8R ( 2000-08-01), p. 5028-
    Abstract: Conventional three-dimensional (3D) ultrasound imaging equipment for diagnosis requires much time to reconstruct 3D images or fix the view point for observing the 3D image. Thus, it is inconvenient for cardiac diagnosis. In this paper, we propose a new dynamic 3D echocardiography system. The system produces 3D images in real-time and permits changes in view point. This system consists of ultrasound diagnostic equipment, a digitizer and a computer. B-mode images are projected to a virtual 3D space by referring to the position of the probe of the ultrasound diagnosis equipment. The position is obtained by the digitizer to which the ultrasound probe is attached. The 3D cardiac image is constructed from B-mode images obtained simultaneously in the cardiac cycle. To obtain the same moment of heartbeat in the cardiac cycle, this system uses the electrocardiography derived from the diagnosis equipment. The 3D images, which show various scenes of the stage of heartbeat action, are displayed sequentially. The doctor can observe 3D images cut in any plane by pushing a button of the digitizer and zooming with the keyboard. We evaluated our prototype system by observation of a mitral valve in motion.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.39.5028
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2000
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
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    Online Resource
  • 6
    Online Resource
    Online Resource
    An Optimization Method for Ultrasonic Beamforming with a Synthetic Aperture
    IOP Publishing ; 1998
    In:  Japanese Journal of Applied Physics Vol. 37, No. 5S ( 1998-05-01), p. 3013-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 37, No. 5S ( 1998-05-01), p. 3013-
    Abstract: Ultrasonic beamforming with a synthetic aperture is widely used in underwater and underground visualizations, but often suffers from visualization results with elliptically symmetric artifacts, due to lack of measurement points or transducers. We propose a newly-developed optimization method for ultrasonic beamforming. The aim of this method is to sharpen the distribution of the point spread function with a limited number of transducers. The characteristic of the point spread function is useful for evaluating the beamforming performance. This optimized beamforming method employs a visualization result by the conventional beamforming method as the initial guess. In the recursive calculation of this optimization method, the initial visualization result is modified by reducing and enhancing the weights of the discretized points in the measurement area. To evaluate this method, we tested it using a computer simulation and an actual measurement experiments, with a limited number of transducers. As the results of the experiments, this method successfully derives a sharp distribution of the point spread function.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.37.3013
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 1998
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
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    Online Resource
  • 7
    Online Resource
    Online Resource
    Three-Dimensional (3D) High-Frequency Ultrasound Images of Skin and an Eye
    IOP Publishing ; 2001
    In:  Japanese Journal of Applied Physics Vol. 40, No. 5S ( 2001-05-01), p. 3931-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 40, No. 5S ( 2001-05-01), p. 3931-
    Abstract: This report describes the three-dimensional (3D) visualization of skin and an eye using high-frequency ultrasound. A high-frequency ultrasound image has high resolution of the order of 10 µm and demonstrates the detailed internal structure of an organ. Therefore it is suitable for visualizing the structure of organs such as skin and the eye. The method of 3D visualization of skin and an eye we used is as follows. Initially, a high-frequency ultrasound image was obtained by using a transducer made of lead zirconate titanate (PZT) ceramics with a central frequency of 32 MHz. The spatial resolution of the image is 25 µm. Next, we applied a binarization procedure to the image and reconstructed a 3D image using a volume-rendering technique. From the results, we were able to separately image each layer of the skin and recognize the stratum corneum, epidermis and dermis. Moreover, we obtained images of the structure of the eye, that is, cornea and iris.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.40.3931
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2001
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
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    Online Resource
  • 8
    Online Resource
    Online Resource
    Intravascular Ultrasonic Imaging with a Micromotor
    IOP Publishing ; 1995
    In:  Japanese Journal of Applied Physics Vol. 34, No. 5S ( 1995-05-01), p. 2865-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 34, No. 5S ( 1995-05-01), p. 2865-
    Abstract: This paper reports a new intravascular imaging system with a micromotor, revolution characteristics of the micromotor and experimental results using a plastic tube. In this system, an ultrasonic beam is scanned radially by the micromotor instead of a scanning wire. The experimental results show that a cross-sectional image of the tube is reconstructed and that this system has a possibility of application to the observation of the inside of a blood vessel.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.34.2865
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 1995
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
    Location Call Number Limitation Availability
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    Online Resource
  • 9
    Online Resource
    Online Resource
    Three-Dimensional Display of Human Heart Motion Using Medical Ultrasonic Images
    IOP Publishing ; 1995
    In:  Japanese Journal of Applied Physics Vol. 34, No. 5S ( 1995-05-01), p. 2861-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 34, No. 5S ( 1995-05-01), p. 2861-
    Abstract: In this paper we report a method for displaying mitral valve motion of a beating heart in a three-dimensional (3-D) image reconstructed from twenty-eight different scanning plane tomograms, each of which consists of twenty successive ultrasonic B-mode images. A 3-D image consists of surface polygon sets to separate the internal and external regions of the heart. The 3-D image is smooth with lighting calculated from vertex normals of polygons. The 3-D mitral valve motion image is obtained from repeated 3-D images in phase in one cardiac cycle. In addition, we display stereoscopic heart images which have angular viewing separation for viewing images, and we obtain spatial relationships of heart anatomy from such images.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.34.2861
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 1995
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
    Location Call Number Limitation Availability
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    Online Resource
  • 10
    Online Resource
    Online Resource
    Compression and Transmission of RF Signals for Telediagnosis
    IOP Publishing ; 2000
    In:  Japanese Journal of Applied Physics Vol. 39, No. 5S ( 2000-05-01), p. 3242-
    Details
    In: Japanese Journal of Applied Physics, IOP Publishing, Vol. 39, No. 5S ( 2000-05-01), p. 3242-
    Abstract: Health care is a critical issue nowadays. Much emphasis is given to quality care for all people. Telediagnosis has attracted public attention. We propose a new method of ultrasound image transmission for telediagnosis. In conventional methods, video image signals are transmitted. In our method, the RF signals which are acquired by an ultrasound probe, are transmitted. The RF signals can be transformed to color Doppler images or high-resolution images by a receiver. Because a stored form is adopted, the proposed system can be realized with existent technology such as hyper text transfer protocol (HTTP) and file transfer protocol (FTP). In this paper, we describe two lossless compression methods which specialize in the transmission of RF signals. One of the methods uses the characteristics of the RF signal. In the other method, the amount of the data is reduced. Measurements were performed in water targeting an iron block and triangular Styrofoam. Additionally, abdominal fat measurement was performed. Our method achieved a compression rate of 13% with 8 bit data.
    Type of Medium: Online Resource
    ISSN: 0021-4922 , 1347-4065
    URL: Article
    DOI: 10.1143/JJAP.39.3242
    RVK:
    UA 4210.1
    RVK:
    UA 4210.2
    RVK:
    UA 4210
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2000
    detail.hit.zdb_id: 218223-3
    detail.hit.zdb_id: 797294-5
    detail.hit.zdb_id: 2006801-3
    detail.hit.zdb_id: 797295-7
    Location Call Number Limitation Availability
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