ABSTRACT
Objective To study the window technique in evaluating the chronic obstructive emphysema and pulmonary residual volume in long-term smoker without symptoms.Methods 50 cases with chronic obstructive emphysema proved clinically,50 long-term smokers were undergone spiral CT scan of chest and compared with 30 health volunteer,the images were designed using the mean CT value in smoking group as window level and two times of ?2 as window width.Results The white imaging was appeared in the most of the group of volunteer,the images were dark on different degree in group one,while the images were as ground glass on different degree in group two.Conclusion This window technique is helpful in evaluating the chronic obstructive emphysema and residual volume of lung in long-term smoker