Subject and nodule characteristics
| Centre A | Centre B | |||
| Benign (695) | Malignant (177) | Benign (710) | Malignant (264) | |
| Age in years, mean (SD) | 61 (12) | 65 (9) | 63 (10) | 64 (9) |
| Sex (%) | ||||
| Male | 434 (62) | 89 (50) | 413 (58) | 157 (59) |
| Female | 261 (38) | 88 (50) | 297 (42) | 107 (41) |
| Emphysema (%) | ||||
| No | 436 (63) | 61 (34) | 555 (78) | 148 (56) |
| Yes | 259 (37) | 116 (66) | 155 (22) | 116 (44) |
| Nodule type (%) | ||||
| Non-solid | 84 (12) | 4 (2) | 50 (7) | 11 (4) |
| Part-solid | 23 (3) | 26 (15) | 42 (6) | 20 (8) |
| Solid | 588 (85) | 147 (83) | 617 (87) | 233 (88) |
| Nodule size (mm) | ||||
| Median | 5.2 | 17.2 | 8.0 | 20.3 |
| IQR | 4.3–8.6 | 11.5–27.8 | 5.9–11.6 | 13.7–31.2 |
| Location (%) | ||||
| Lower lobe | 368 (53) | 60 (34) | 378 (53) | 99 (37) |
| Upper lobe | 327 (47) | 117 (66) | 332 (47) | 165 (63) |
| Nodule count | ||||
| Median | 4 | 3 | 6 | 2 |
| IQR | 2–5 | 1.5–4 | 2–11 | 1–3 |
| Spiculation (%) | ||||
| No | 694 (99.9) | 156 (88) | 702 (99) | 193 (73) |
| Yes | 1 (0.1) | 21 (12) | 8 (1) | 71 (27) |
IQR from the 25th to the 75th percentile.