The Application Of Low Dose CT Scanning In Solitary Pulmonary Nodules Biopsy

Objective: To investigate the feasibility and clinical value of the low dose CT scanning guided percutaneous isolated lung nodule biopsy.Methods: Eighty patients with isolated lung nodule were included in this study. Before taking spiral CT guided percutaneous lung nodule biopsy, all patients were randomly divided into two groups: low dose group(120 k V, 20 m As), and regular dose group(120 k V, automated tube current), 40 patients in each group. In all the patients, the maximum diameter of lesions were 8.6 ~29.8 mm(20.8 mm in average) and the weight of patients was 42 ~ 98 kg(62 kg in average). There were 27, 30, 6, 8, 9 cases in right upper lobe, left upper lobe, right middle lobe, right lower lobe and left lower lobe respectively, in which 8 cases in left lingular segment. The final diagnosis were all confirmed by surgically pathologic result or follow-up. The biopsy result was defined as positive if it was concordant with the final diagnosis..Results: There was no statistically significant differences in age(t=0.21, P>0.05), gender(c2=0.53, P>0.05), lesion to pleural depth(c2=0.53, P>0.05), nodule size(c2=0.53, P>0.05) and lesion location(P>0.05) between two groups. The ratio of image quality level 2 of the low dose group was lower than that of the conventional dose group, but there was no significant differences in the ratio of biopsy guarding capable image(≧level 2) between two groups. The CTDIvol index and effective radiation dose in low dose group was 20% and19.8% of that of conventional group, respectively. The variance analysis showed that effective radiation dose was significantly different between two groups. There was 37 true-positive cases and 3 false-negative cases in low dose group, and biopsy accuracy was 92.5%. There was 38 true-positive cases and 2 false-negative cases in conventional dose group, and biopsy accuracy was 95.0%. The total complication rate, the incidence of pneumothorax and the incidence of pulmonary hemorrhage were 12.5%(5/40) and 10%(4/40), 7.5% and 5.0%, and 5.0% and 5.0% in low dose group and conventional group, respectively. There was no severe complication in these two groups. There was no statistically significant difference in biopsy positive rate(c2=0.213, P=0.644), the incidence of pneumothorax(c2=0.188,P=0.664) and pulmonary hemorrhage(c2=0, P=1.002) between two groups.Conclusions:Low-dose spiral CT guided percutaneous lung biopsy is an accurate, efficient, safe and minimally invasive method, reducing the radiation dose, keeping the relatively high puncture success rate and low complication rate, therefore this technique has high clinical application value.