Japanese Journal of Radiological Technology
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
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Volume 69, Issue 8
Displaying 1-10 of 10 articles from this issue
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  • Development of Temporal Subtraction Method for Chest Radiographs by Using Pixel Matching Technique
    Aiko Sugimoto, Shigehiko Katsuragawa, Yoshikazu Uchiyama, Junji Shirai ...
    2013 Volume 69 Issue 8 Pages 855-863
    Published: August 20, 2013
    Released on J-STAGE: August 21, 2013
    DOIhttps://doi.org/10.6009/jjrt.2013_JSRT_69.8.855
    JOURNAL FREE ACCESS
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    A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can enhance interval changes on a chest radiograph by removal of most normal structures. However, subtraction artifacts, which tend to reduce its effectiveness in the detection of interval changes, were still included in the conventional method. In this study, we have developed a pixel matching technique to reduce artifacts in the temporal subtraction images. With this technique, the pixel value in a nonlinearly warped previous image is replaced by a pixel value within a kernel, which is closest to the pixel value on a current image. For evaluation of the proposed method, one hundred temporal subtraction images with a simulated nodule were used. When the kernel size of 3×3 was employed in the pixel matching technique, the misregistration artifacts decreased by 72%, and the contrast-to-noise ratio of the simulated lung nodules was increased by 5% in comparison with the conventional method. However, the area of the simulated nodule on the subtraction image decreased by 6%. Our results indicated that the pixel matching technique can enhance simulated nodules, with a substantial reduction of misregistration artifacts in comparison with conventional subtraction images. Therefore, we believe that the temporal subtraction method with the pixel matching technique would assist radiologists’ diagnoses for detection of lung nodules in digital chest radiography.
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  • Proposal for Contrast-amplified Image Reconstruction Methods by Adjusting Computed Tomography Value Scale in Three-dimensional Image Processing
    Ryo Watanabe, Masato Ogawa, Masataka Shiotani, Takahiro Aoki, Mizuho H ...
    2013 Volume 69 Issue 8 Pages 864-872
    Published: August 20, 2013
    Released on J-STAGE: August 21, 2013
    DOIhttps://doi.org/10.6009/jjrt.2013_JSRT_69.8.864
    JOURNAL FREE ACCESS
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    To create three-dimensional computed tomography angiography (3D-CTA) images of blood vessels, it is important to acquire a high-contrast original image of the blood vessels and the surrounding tissues. However, reexamination is likely to be needed if, due to the condition of the examinee, insufficient contrast enhancement is achieved. This prompted us to design a method of amplifying image contrast using software that simply adds the CT value to each corresponding pixel of the original image, i.e., the same image is added after the scan. This prevents spatial and time discontinuities with the original image. The CT value of the original image can also be increased arbitrarily to any value by adjusting the weighting level of the added image. The difference in CT values between the pixels can thus be amplified without changing the contours of the original image. Since this method enables the original image’s contrast to be amplified by post-processing, i.e., without increasing radiation load exposure or employing additional contrast medium, it is a technique with high clinical utility.
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Note
  • Influence of Heart Rhythm, Breathing and Arm Position during Computed Tomography Scanning on the Registration Accuracy of Electro Anatomical Map (EAM) Images, Left Atrium Three-dimensional Computed Tomography Angiography Images, and Fluoroscopy Time during Ablation to Treat Atrial Fibrillation
    Taiki Chono, Shinya Shimoshige, Kenta Yoshikawa, Kazuhusa Mizonobe, Ke ...
    2013 Volume 69 Issue 8 Pages 873-878
    Published: August 20, 2013
    Released on J-STAGE: August 21, 2013
    DOIhttps://doi.org/10.6009/jjrt.2013_JSRT_69.8.873
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    Background: In CARTOMERGE® for treatment of atrial fibrillation (AF) by ablation, by integrating electro anatomical map (EAM) and left atrium three-dimensional computed tomography angiography (3D-CTA) images, identification of the ablation points is simplified and the procedure can be made carried out more rapidly. However, the influence that heart rhythm, breathing and arm position during CT scanning have on registration accuracy and fluoroscopy time is not clear. Purpose: To clarify the influence on registration accuracy and fluoroscopy time of heart rhythm, breathing and arm position during CT scanning. Methods: The patients were CT-scanned during both sinus rhythm (SR) and AF in each study subject. We evaluated the registration accuracy of images reconstructed between the cardiac cycle and assessed the registration accuracy and fluoroscopy time of images obtained during inspiratory breath-hold, expiratory breath-hold and up and down position of the arm. Results: Although the registration accuracy of the EAM image and left atrium 3D-CTA image showed a significant difference during SR, no significant difference was seen during AF. Expiratory breath-hold and down position of the arm resulted in the highest registration accuracy and the shortest fluoroscopy time. However, arm position had no significant effect on registration accuracy. Conclusions: Heart rhythm and breathing during CT scanning have a significant effect on the registration accuracy of EAM images, left atrium 3D-CTA images, and fluoroscopy time.
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Data
  • Abbreviations of Special Terms for Presentation/Paper Titles in Magnetic Resonance Study
    Masanori Komi, Junji Shiraishi
    2013 Volume 69 Issue 8 Pages 879-883
    Published: August 20, 2013
    Released on J-STAGE: August 21, 2013
    DOIhttps://doi.org/10.6009/jjrt.2013_JSRT_69.8.879
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    Purpose: A large number of abbreviations have been created for various special terms, and used in magnetic resonance (MR) study. However, the use of these abbreviations in the paper title has been restricted by the majority of societies and journals. In this study, we investigated the use of various abbreviations for special terms in MR study in order to clarify which abbreviation could be used in the paper title without spelling. Materials and Methods: We used two journals, Magnetic Resonance in Medicine (MRM) and Journal of Magnetic Resonance Imaging (JMRI) published by the International Society for Magnetic Resonance in Medicine (ISMRM), which has been considered to be the most advanced society for MR study in the world, as the reference standard for use of the abbreviations. Results: Except for some basic abbreviations and specific abbreviations that were used on a long-term basis, the majority of abbreviations were used in the paper title with its full spelling in order to ensure generality. Conclusion: It is preferable that abbreviations not be used in the title of the or title of the paper.
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Educational Lecture—Statistical Methods for Radiologic Research
Basic Lecture—Three-dimensional Computer Graphics
Basic Lecture—Heart Disease: From Diagnosis to Treatment
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