RT Journal Article SR Electronic T1 A new method for evaluation of severity in COPD using dynamic chest x-ray examination JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P271 VO 40 IS Suppl 56 A1 Norihisa Motohashi A1 Misako Aoki A1 Takehiko Abe A1 Yuji Shiraishi A1 Hideo Ogata A1 Shoji Kudoh YR 2012 UL http://erj.ersjournals.com/content/40/Suppl_56/P271.abstract AB Purpose: Spirometry which requires maximum effort tasks COPD patients. In this study, we purposed a new method for evaluation of severity in COPD using dynamic chest X-ray examination without effort breathing.Subjects: Dynamic chest X-ray from 29 normal volunteers, 30 mild COPD patients (GOLD Stage I or II) and 31 severe COPD patients (GOLD Stage III or IV) were obtained in the upright position in about 10 seconds of tidal breathing at rest. The dynamic image data captured at 7.5 frames per second was synchronized with the pulsed X-ray. The institutional review board approval and written informed consent were obtained in all persons.Methods: We calculated the maximal differential values in each ventilation phase at the corresponding small local area of lung in the series of dynamic chest X-ray. The regional relative flow rate ratio was obtained from the peak values of inspiratory phase divided by the peak values of expiratory phase. All groups were compared about the standard deviation of flow rate ratio.Results: The average of the ratio in normal volunteers, in mild COPD patients and in severe COPD patients were 0.21±0.03, 0.22±0.04 and 0.26±0.04 (mean±SD),respectively. Significant difference was confirmed between the normal volunteers and the severe COPD patients (p=0.00047), and between the the mild COPD patients and the severe COPD patients (p=0.0092),respectively.Conclusion: The variation of the inspiratory / expiratory flow rate ratios in COPD patients were larger than those of healthy volunteers. The new method for ventilation function has possibility to evaluate severity of COPD.