Number of passes Number of cases Pneumothorax Negative Positive NA Rates of pneumothorax 1 or 2 79 53 22 4 29.3 % (22/75) 3 or 4 94 60 28 6 31.8 % (28/88) 5 or above 42 27 14 1 34.1% (14/41)

Table 4: Comparison of core needle biopsies with different number of passes.