| Project/Area Number |
11470139
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Respiratory organ internal medicine
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MISHIMA Michiaki Kyoto University, Medicine, Professor, 医学研究科, 教授 (60190625)
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| Co-Investigator(Kenkyū-buntansha) |
CHIN Kazuo Kyoto University, Medicine, Associate Professor, 医学研究科, 助教授 (90197640)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Pulmonary Emphysema / Chronic Bronchitis / COPD / CT / Fractal analysis / 慢性閉塞性肺疾患 / 胸部CT / 気道病変 / 低吸収領域 / LAA% / WA% / 気道壁 / 気管 |
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| Research Abstract |
Fractal properties are defined as a self-similarity with the different size of view, and the lung perfusion and airway branching have been reported to hava fractal propertice. We found that the size of cluster of the low attenuation area (LAA clusters) corresponding to pulmonary emphysema, and the cumulative number has a linear relationship in the log-log plot. These results suggest that the distribution of LAA clusters have a fractal distribution and that the LAA% ranged from 5% to 60%, and a half of COPD group have the normal LAA% (<30%) The fractal dimension (Df) calculated from the slope of log-log plot in COPD group with normal LAA% has smaller values than those in normal group.These results prove that COPD has a langer LAA clusters, and that the Df is a better index to find early emphysema than LAA%. The simulation using an elastic spring network model was then performed to clarify the relationship between the process of emphysema and fractal dimension. The simulation indicated t
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hat the tissue between the neighboring LAA clusters was subject to the large share stress and was easy to be destroyed, and the two LAA clusters became one cluster. This process showed the little effect on the increase of LAA% whereas the Df values predominantly decreased that the same process may be developing in the practical lung with early emphysema. The visual estimation of airway dimension such as the size of airway lumen (Ai) and airway wall thickness (T) has been performed in patients with bronchial asthma.However, the visual estimation is highly subjiective,and was not perfmed for COPD. We developed the automatic system for analyzing airway dimension,and applied it to patients with COPD The right apical bronchus (B) was analyzed because the helical CT can tangentially cut the right B.COPD had smaller Ai and Ai/BSA(body surface area),and langer T,T/BSA0.5, and WA%(ratio of wall area to whole area of airway) than normal controls. The contribution of LAA%(index of emphysema) and WA%(index of bronchitis) on the lung function indicationg airflow limitation was then estimated using multiple regression analysis. It was found that LAA% and WA% determine independently the airflow limitation, which is the definition of COPD. These results suggested that we can distinguish pulmonary enphysema and chronic bronchitis from COPD patients using CT inages. Thus, the analysis of CT images may have a great contribution on the understanding the pathogenesis and developing the new therapy of COPD. Less
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