To compare the outcome measures of interest between the two biopsy methods, continuous variables are summarized by median (inter-quartile range; IQR) and tested by the Wilcoxon-rank-sum test, and categorical variables are summarized by frequency (percentage) and tested by Fisher’s exact test, with \(p\)-values less than 0.05 considered statistically significant. To ensure that the sample of patients who received CTF had location and size proportions that matched those observed in the electromagnetic navigation patients, a stratified random sampling scheme was utilized where location and size was the stratum. Due to this sampling scheme, the statistical inference resulting from the two-group comparisons described above does not generalize to the overall patient population, but rather it more appropriately generalizes to the population that provided the electromagnetic navigation sample.
| EMN (N=50) | CTF (N=100) | p-value | |
|---|---|---|---|
| Sex - female | 22 (44%) | 35 (35%) | 0.291 |
| Sex - male | 28 (56%) | 65 (65%) | |
| Age (years) | 65 (58, 70.8) | 65 (58.5, 73) | 0.596 |
| Target size (cm) | 2 (1.5, 2.9) | 2.1 (1.5, 2.9) | 0.751 |
| Skin-to-target distance (cm) | 11.4 (9.4, 13.4) | 10.7 (9.1, 12.6) | 0.195 |
| Technical success - No | 1 (2%) | 0 (0%) | 0.333 |
| Technical success - Yes | 49 (98%) | 100 (100%) | |
| No. of cores | 3 (2, 4) | 3 (2, 4) | 0.64 |
| Intro needle - 17 | 45 (90%) | 77 (77%) | 0.074 |
| Intro needle - 19 | 5 (10%) | 23 (23%) | |
| Nondiagnostic - No | 49 (98%) | 95 (95%) | 0.664 |
| Nondiagnostic - Yes | 1 (2%) | 5 (5%) | |
| Benign - No | 35 (70%) | 78 (78%) | 0.318 |
| Benign - Yes | 15 (30%) | 22 (22%) | |
| False negative - No | 50 (100%) | 99 (99%) | 1 |
| False negative - Yes | 0 (0%) | 1 (1%) | |
| Complications - No | 49 (98%) | 95 (95%) | 0.664 |
| Complications - Yes | 1 (2%) | 5 (5%) | |
| Patient effective dose (mSv) | 21.1 (14.7, 40.1) | 5.5 (2.9, 10.1) | <0.001 |
| Radiation dose to operator (µGy) | 0 (0, 0) | 0.9 (0.6, 1.5) | <0.001 |
| Procedure time (min) | 33 (27.2, 40.8) | 31 (22, 40) | 0.274 |
| No. of CTF scans | 0 (0, 0) | 24 (18, 35) | <0.001 |
| No. of helical scans | 4 (3, 5) | 1.5 (1, 3) | <0.001 |
| CT tilt out of plane - No | 50 (100%) | 97 (97%) | 0.551 |
| CT tilt out of plane - Yes | 0 (0%) | 3 (3%) | |
| Angle out of plane | 10.3 (3.6, 18.2) | NA | – |
Categorical variables are summarized by N (%) and quantitative variables by median (IQR). p-value is based on Wilcoxon-rank-sum test for quantitative variables and Fisher’s exact test for categorical variables.