Comparison of low-dose and standard-dose helical CT in the evaluation of pulmonary

The purpose of this study was to investigate the diagnostic ac- curacy of low-dose helical computed tomography by comparing the num- ber of nodules detected at low- and standard-dose CT. The prospective study included 25 patients who were referred to CT scan for the assess- ment of pulmonary metastases. All patients underwent CT examinations at both standard- (200 mA, 120 kV, collimation 5 mm, table feed 10 mm per rotation) and low-dose (50 mA, 120 kV, collimation 5 mm, table feed 10 mm per rotation). The number of nodules detected at each protocol was recorded. The size of the nod- ules was measured electronically and categorized as 0.05). Four hundred ninety-one (87.7%) nodules were de- tected at both standard- or low-dose CT, 42 (7.5%) nodules were ob- served only at standard-dose CT, and 27 (4.8%) nodules were seen only at low-dose CT. The sensitivity of low- dose CT was 92.5% for all nodules, 88.1% for nodules <5 mm, and 97.4% for nodules ≥5 mm. No sig- nificant image artifact interfering with nodule detection was observed at low-dose CT. The low-dose CT protocol used in this study provided images of adequate quality; thus, it can be used reliably in the detection or exclusion of pulmonary nodules.