CT-guided transthoracic needle aspiration biopsy of pulmonary nodules: needle size and pneumothorax risk

Abstract

Radiology 2003;229:475–81. Geraghty PR, Kee ST, Mcfarlane G, et al. Comments: The purpose of this study was to evaluate the effect of the size of the coaxial needle on pneumothorax rate and the diagnostic accuracy of computed tomography (CT)-guided transthoracic needle aspiration biopsy (TNAB). The authors retrospectively reviewed data of 846 patients who underwent a CT-guided TNAB. Approximately 40% of patients were smokers, but the information regarding how many patients had chronic obstructive pulmonary disease is not provided. The mean diameter of the lesion was 3.02 cm. The initial 324 patients underwent the procedure with an 18-gauge needle, and the remaining 522 patients had the procedure done with an 19-gauge needle. The sensitivity, specificity, and the accuracy of the diagnosis were calculated using 18-month follow-up data from 676 patients. Overall, complications developed in 252 (30%) of 846 patients after the procedure. Pneumothorax was the most common complication, which was seen in 226 (26.7%) patients. The incidence of pneumothorax after TNAB was significantly higher with the 18-gauge needle than with the 19-gauge needle (38% vs. 23%, P <0.001), even when adjusted for other variables such as sex, age, size of the lesion, and so on. Catheter aspiration was needed in 69 patients (8.2%), and a chest tube was needed in 74 (8.6%). The incidence of chest tube placement was similar irrespective of the needle used for TNAB. No independent correlation was observed between the size of the lesion and the pneumothorax rate. Overall sensitivity, specificity, and accuracy were 95%, 100%, and 96%, respectively, for the 18-gauge needle, and 89%, 99%, and 92%, respectively, for the 19-gauge needle. The difference was not statistically significant. In the coaxial system, a larger-gauge needle is inserted to the edge of the lesion under image guidance, and a smaller needle is passed through it to obtain the specimen (Clin Chest Med 2002;23:137–58). This allows the operator to obtain specimens several times without needing to puncture the visceral pleura several times. The results from this study indicate the risk of pneumothorax is reduced by nearly 50% when the coaxial biopsy system uses an 19-gauge needle for TNAB as compared with an 18-gauge needle. The diagnostic yield was similar for both of the needles. Unfortunately, the authors do not provide information regarding the distance of the lesion from the chest wall and the proportion of patients with chronic obstructive pulmonary disease in 2 groups of patients. Difference in patient population with regard to these 2 characteristics could have confounded the study results. Nevertheless, based on the study results, it seems reasonable to choose 19-gauge needles for TNAB procedures that use the coaxial system.