| Project/Area Number |
02670495
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Radiation science
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| Research Institution | Osaka University |
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Principal Investigator |
IKEZOE Junpei (1991) Osaka University, Radiology, Asst. Professor, 医学部, 講師 (70115989)
森本 静夫 (1990) 大阪大学, 医学部, 講師 (60116118)
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| Co-Investigator(Kenkyū-buntansha) |
ARISAWA Jun Osaka University, Radiology, Research Asst., 医学部, 助手 (40144513)
池添 潤平 大阪大学, 医学部, 講師 (70115989)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1990: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | gravity-depend Atelectasis / nonradioactive Xenon / dynamic Inhalation CT / ゼノンガス混合酸素 / 呼吸不全 |
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| Research Abstract |
Reduction, in lung volume and shallow breathing produce progressive atelectasis in the dorsal lung(gravity-dependent atelectasis : GDA). We have developed an animal model of GDA(Invest Radiol 24 : 522, 1'989). The purpose of this study is to determine whether airway occlusion is a key factor for GDA.
Methods : Dynamic inhalation CT was performed in ten rabbits, using 50%'iionradioactive xenon in oxygen on high frequency oscillatory ventilation(HFOV). Time-CT value curves were. -assumed to be described as exponential function, C=C_o(1-e^<-Kt>)(Kety's model). K value, which is equal to alveolar ventilation /alveolar volume, was calculated with re. gres. sion analysis. I. n experimental group(n=5)lung volume was reduced with artificial pneumoperitoneus of 10 cmH_2, while control group(n=5)did not have pneuxoperitoneum. Both groups were placed on HFOV for six hours and K values were calculated every one hour.
Results : In all of the experimental group GDA was formed. In the dorial regions. wash-in of xenon. was observed and' K values increased just before GDA appeared'' Meanwhile K values in the ventral regions did not change significantly. The control group did not reveal-GDA'and K values did not change in either region.
Conclusions : GDA is. related to the increase in alveolar ventilation /alveolar volume ratio. This result suggests that GDA is not caused. by airway occlusion. By means of this procedure-we can. diagnose GDA before"' the decrease in arterial oxygen pressure or. detection on CT images.
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