Medical Imaging Technology
Online ISSN : 2185-3193
Print ISSN : 0288-450X
ISSN-L : 0288-450X
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Volume 33, Issue 5
Displaying 1-9 of 9 articles from this issue
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Selected Papers from the JAMIT 2015 Annual Meeting ‹Work-in-progress›
  • Automatic Detection Method for Architectural Distortion Using Iris Filter Together with Gabor Filter in the Breast X-ray Image
    Mizuki YAMAZAKI, Tomoko OTSUKA, Atsushi TERAMOTO, Hiroshi FUJITA
    2015 Volume 33 Issue 5 Pages 197-202
    Published: 2015
    Released on J-STAGE: November 27, 2015
    DOIhttps://doi.org/10.11409/mit.33.197
    JOURNAL FREE ACCESS
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    In recent years, computer-aided diagnosis (CAD) has been expecting to improve the diagnostic performance and to reduce the oversight of a lesion. CAD is used for breast X-ray images. However, there is a challenge about the poor detection accuracy of architectural distortion that is the most missing findings. In this study, we propose the hybrid detection method that integrates two detection methods of massive patterns and architectural distortion to improve the lesion detection sensitivity. We applied to the adaptive Gabor filter for the detection of the architectural distortion and to the iris filter for the detection of the mass. Candidate regions are obtained by calculation of the concentration index using filtered images. In the experiments, we compared the results of proposed method and physician interpretation report using 200 images (63 architectural distortions) of digital database of screening mammography. As a result, the conventional method had true positive rate (TPR) of 73.0% and the number of false positives (FPs) of 0.65 per image. Whereas TPR of proposed method was 79.4% and FPs were 1.88 per image. These results indicate that our method may be effective to improve the performance of computer aided detection in breast X-ray images.
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  • Observation of Rat's Testis by Crystal-based Phase Contrast X-ray CT
    Kei TERAZAKI, Thet Thet Lwin, Akio YONEYAMA, Hiroko MARUYAMA, Kazuyuki ...
    2015 Volume 33 Issue 5 Pages 203-207
    Published: 2015
    Released on J-STAGE: November 27, 2015
    DOIhttps://doi.org/10.11409/mit.33.203
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    Conventional X-ray absorption imaging method detects the difference of the linear absorption coefficient. The absorption difference of the soft tissue consisting of light elements is very small, so the discrimination of inner structure is difficult without contrast agent. On the other hand, the sensitivity for the light element of the phase contrast method, is higher approximately 1000 times than the X-ray absorption imaging method. Using crystal-based phase contrast X-ray technique, biological soft tissue can be visualized non-destructively, and the formalin fixed normal rat's testis was observed in this study. Crystal-based phase contrast X-rays CT depicted 100-200 μm seminiferous tubules, septa testis, albuginea and an epididymis in a testis. CT images were similar to an optical microscope with HE staining. Thus, the testicular structure including seminiferous tubule might be assessed by crystal-based phase contrast X-rays CT easily.
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Papers
  • Extract Cell Body Region from Microscopic Image of Podocyte and a Trial of Discrimination of Cellular Degeneration by Signal Regulatory Protein α and Diabetes Mellitus
    Shusuke MOTOKAWA, Tsutomu MATSUURA, Takeo AOKI
    2015 Volume 33 Issue 5 Pages 208-216
    Published: 2015
    Released on J-STAGE: November 27, 2015
    DOIhttps://doi.org/10.11409/mit.33.208
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    In evaluation of image, the results provided by image processing and statistical processing are more objective than those which are judged by visual observation. We propose a method to create a binary image of cell body region from a local area image of Podocyte. The structure of Podocyte is changed by disease. In order to capture this change, we use electron microscope image of Podocyte and select five kinds of mice; wild type, mouse with diabetes mellitus, aged mouse, knockin mouse and knockin mouse with diabetes mellitus. We use contrast adjustment and opening of mathematical morphology for preprocessing to define outline of a cell. And for getting the binary image, we adopt Sauvola method which is a kind of dynamic thresholding. After that we calculate area and circularity of cell body regions to examine difference among five types of mice. From this calculation we can find that the features of wild type mice get near to those of knockin mice as they become diabetic or old. This study includes trial-and error procedure when we should decide some parameters in image processing. To decide these suitable parameters by calculation is a future task.
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  • One-dimensional Noise Power Spectrum Measurement in PROPELLER MR Imaging
    Yuki ICHINOSEKI, Kota MIYAMOTO, Toshiki SAITO, Issei MORI, Yoshio MACH ...
    2015 Volume 33 Issue 5 Pages 217-222
    Published: 2015
    Released on J-STAGE: November 27, 2015
    DOIhttps://doi.org/10.11409/mit.33.217
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    From results of a previous study examining a two-dimensional Noise Power Spectrum (2D NPS) of a PROPELLER MR image, we have been presented that the 2D NPS reflects the k-space data sampling density and shows agreement with the k-space trajectory shape. In X-ray imaging, one-dimensional NPS (1D NPS) is also used because it can easily accommodate and analyze the NPS data numerically. As described herein, we studied the 1D NPS of a PROPELLER MR image using two typical measuring methods: “radial frequency method” and “hypothetical slit method”. Results showed that the 1D NPS generated using the latter method reflects the change of the NPS values on the 2D NPS along with a direction of slit scanning, whereas the 1D NPS by the former method shows the averaged NPS values with the same spatial frequency. We also confirmed the measuring precision of the NPS values. The radial frequency method assures high precision.
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Tutorial
  • The Latest Technology Trends in CT Screening (1): Exposure Dose Control in CT Screening
    Rikuta ISHIGAKI, Yoshito TABATA, Masato MORI
    2015 Volume 33 Issue 5 Pages 223-226
    Published: 2015
    Released on J-STAGE: November 27, 2015
    DOIhttps://doi.org/10.11409/mit.33.223
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    CT scanning can be expected to provide not only a qualitative diagnosis, but also early disease detection. Accordingly, these advantages from CT screening have an important role in preventive medicine. On the other hand, CT examination unavoidably involves a high dose of radiation exposure. As such exposures would be considered disadvantageous for healthy individuals who are recommended to receive annual CT screenings, the dose of radiation is expected to be kept to the minimum essential level. On the subject of radiation dose control, this paper reports on the trends, standards, operations and applications, how the CT screening quality control system is integrated within the practice, and efforts made in Japan and the United States.
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Editors’ Note
Cumulative Index Vol. 33
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