Quantitative and Qualitative Assessments of Lung Destruction and Pulmonary Functional Loss from Reduced-Dose Thin-Section CT in Pulmonary Emphysema Patients

Rationale and Objectives: Academic and clinical interest in reducing radiation from computed tomography (CT) examinations has increased, and the purpose of this study was to determine the capabilities of reduced-dose multidetector-row CT (MDCT) in assessing lung destruction and pulmonary functional loss in pulmonary emphysema patients. Materials and Methods: Twenty-five consecutive smokers (15 men and 10 women; mean age 67.9 years; age range 49-86 years) underwent MDCT examinations using two different effective tube currents (standard-dose protocol [150 mAs] and reduced-dose protocol [50 mAs]). For quantitative and qualitative assessments of lung destruction in each subject, percentage of low attenuation emphysematous destruction areas (%LAAs) were computationally calculated, and visual emphysema scores (ESs) were determined for both protocols. To determine the capabilities for quantitative and qualitative assessments of lung destruction by using reduced-dose protocol, %LAAs and ESs of both protocols were compared statistically. To compare the capabilities for quantitative and qualitative assessments of pulmonary functional loss, %LAAs and ESs of both protocols were correlated with forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC). Results: %LAAs and ESs had significant correlations between both protocols (%LAAs: r = 0.95, P < .001; ESs: r = 0.97, P < .001). The limits of agreement of %LAAs were -1.8 ± 9.2%. The agreement of ESs between both protocols was substantial (κ = 0.70). %LAAs and ESs of both protocols had significant correlations with FEV1/FVC (%LAAs of 150 mAs: r = -0.49, P < .05; %LAAs of 50 mAs: r = -0.44, P < .05; ESs of 150 mAs: r = -0.67, P < .001; ESs of 50 mAs: r = -0.66, P < .001). Conclusion: Reduced-dose MDCT had a potential of substitution for standard-dose MDCT on the both assessments in pulmonary emphysema patients.