Learning Curve for CT-Guided Percutaneous Transthoracic Needle Biopsy: Retrospective Evaluation Among 17 Thoracic Imaging Fellows at a Tertiary Referral Hospital.

. CT-guided percutaneous transthoracic needle biopsy (PTNB) is widely used for evaluation of indeterminate pulmonary lesions, although guidelines are lacking regarding the experience needed to gain sufficient skill. . The purpose of our study was to investigate the learning curve among a large number of operators in a tertiary referral hospital and to determine the number of procedures required to obtain acceptable performance. . This retrospective study included CT-guided PTNBs with coaxial technique performed by 17 thoracic imaging fellows from March 2, 2011, to August 8, 2017, who were novices in the procedure. A maximum number of 200 consecutive procedures per operator were included. The cumulative summation method was used to assess learning curves for diagnostic accuracy, false-negative rate, pneumothorax rate, and hemoptysis rate. Operators were assessed individually and in a pooled analysis. Pneumothorax risk was also assessed in a model adjusting for risk factors. Acceptable failure rates were defined as 0.1 for diagnostic accuracy and false-negative rate, 0.45 for pneumothorax rate, and 0.05 for hemoptysis rate. . The study included 3261 procedures in 3134 patients (1876 men, 1258 women; mean age, 67.7 ± 12.1 [SD] years). Overall diagnostic accuracy was 94.2% (2960/3141). All 17 operators achieved acceptable diagnostic accuracy (37 procedures required in the pooled analysis; median, 33 procedures required [range, 19-67 procedures required]). Overall false-negative rate was 7.6% (179/2370). All 17 operators achieved acceptable false-negative rate (52 procedures required in the pooled analysis; median, 33 procedures required [range, 19-95 procedures required]). Pneumothorax occurred in 32.6% of the procedures (1063/3261 procedures), and hemoptysis occurred in 2.7% of the procedures (89/3261 procedures). All 17 operators achieved acceptable pneumothorax rate (20 procedures required in the pooled analysis; median, 19 procedures required [range, 7-63 procedures required]). In the risk-adjusted model, 15 operators achieved acceptable pneumothorax rate (54 procedures required in the pooled analysis; median, 36 procedures required [range, 10-192 procedures required]). Sixteen operators achieved acceptable hemoptysis rate (67 procedures required in the pooled analysis; median, 55 procedures required [range, 41-152 procedures required]). . For CT-guided PTNB, at least 37 and 52 procedures are required to achieve acceptable diagnostic accuracy and false-negative rate, respectively. Not all operators achieved acceptable complication rates. . The findings may help set standards for training, supervision, and ongoing assessment of operator proficiency for this procedure.