RESUMO
Objective To study the value of reverse CT scan in eliminating the respiratory motion artifacts in the thoracic CT of the patients with chronic obstructive pulmonary diseases(COPD).Methods Fourty patients with COPD were randomly selected and underwent chest CT examinations with the technique of GR-Helical including directive and reverse CT scans.The images were blindly evaluated by three experienced doctors.Results In 40 cases,the respiratory motion artifacts were present in 17 cases,among them,70.59%(12/17) artifacts was in lower lung field,and 64.7%(11/17) artifacts occurred in the people over 60 years of age.The rate of artifact was 35% at directive scan,while it was reduced to 7.5% at reverse scan,the image quality was improved at 27.5%.There was statistical significance in eliminating respiratory motion artifacts between two scanning method (P＜0.05).Conclusion Reverse CT scanning can effectively eliminating or reducing the respiratory motion artifacts in lower lung field,it is the best choice of scanning mode in elderly patients with COPD.