Table 1. Demographic characteristics.
| Basic characteristics | Total | Benign | Malignant | P value |
|---|---|---|---|---|
| Patient | 1,004 (100.0) | 724 (72.11) | 280 (27.89) | – |
| Sex | 0.10 | |||
| Female | 828 (82.47) | 606 (83.70) | 222 (79.29) | |
| Male | 176 (17.53) | 118 (16.30) | 58 (20.71) | |
| Age (years) | 48.00 (38.00, 57.00) | 49.00 (38.00, 58.00) | 47.00 (37.50, 55.50) | 0.07 |
| Nodule | 1,228 (100.0) | 936 (76.22) | 292 (23.78) | – |
| Size (mm) | 25.00 (13.00, 35.00) | 28.50 (18.25, 37.00) | 12.00 (8.00, 18.00) | <0.001 |
| Composition | ||||
| Solid or purely solid | 697 (56.76) | 420 (44.87) | 277 (94.86) | <0.001 |
| Mixed | 510 (41.53) | 495 (52.88) | 15 (5.14) | <0.001 |
| Cystic, purely cystic or spongiform | 21 (1.71) | 21 (2.25) | 0 (0.00) | 0.007 |
| Echogenicity | ||||
| Very hypoechoic | 82 (6.68) | 19 (2.03) | 63 (21.58) | <0.001 |
| Hypoechoic | 752 (61.24) | 539 (57.59) | 213 (72.95) | <0.001 |
| Hyperechoic or isoechoic | 374 (30.46) | 358 (38.25) | 16 (5.48) | <0.001 |
| Anechoic | 20 (1.62) | 20 (2.13) | 0 (0.00) | 0.007 |
| Shape | ||||
| Taller than wider (on transverse section) | 117 (9.53) | 25 (2.67) | 92 (31.51) | 0.91* |
| Wider than taller (on transverse section) | 1,111 (90.47) | 911 (97.33) | 200 (68.49) | <0.001 |
| Taller than wider (on transverse or longitudinal section) | 132 (10.75) | 29 (3.10) | 103 (35.27) | |
| Wider than taller (on transverse or longitudinal section) | 1,096 (89.25) | 907 (96.90) | 189 (64.73) | <0.001 |
| Margin | ||||
| Extrathyroidal extension | 34 (2.77) | 6 (0.64) | 28 (9.59) | <0.001 |
| Irregular or lobulated | 242 (19.71) | 44 (4.70) | 198 (67.81) | <0.001 |
| Smooth or ill-defined | 952 (77.52) | 886 (94.66) | 66 (22.60) | <0.001 |
| Echogenic foci | ||||
| Microcalcifications and macrocalcifications | 1 (0.08) | 0 (0) | 1 (0.34) | 0.24 |
| Microcalcifications | 211 (17.18) | 45 (4.81) | 166 (56.85) | <0.001 |
| Peripheral calcifications | 29 (2.36) | 24 (2.56) | 5 (1.71) | 0.40 |
| Macrocalcifications | 93 (7.56) | 66 (7.05) | 27 (9.25) | 0.22 |
| None or large comet-tail artifacts | 894 (72.80) | 801 (85.58) | 93 (31.85) | <0.001 |
| Multifocal high-suspicion nodules† | 0.08 | |||
| Yes | 293 (23.86) | 212 (22.65) | 81 (27.74) | |
| No | 935 (76.14) | 724 (77.35) | 211 (72.26) | |
| Immediately adjacent to the capsule, trachea or the recurrent laryngeal nerve | <0.001 | |||
| Yes | 692 (56.35) | 480 (51.28) | 212 (72.60) | |
| No | 536 (43.65) | 456 (48.72) | 80 (27.40) | |
| Cervical metastatic lymph nodes | <0.001 | |||
| Yes | 9 (0.73) | 0 (0.00) | 9 (3.08) | |
| No | 1,219 (99.27) | 936 (100.0) | 283 (96.92) |
Data are presented as number (%) or median (interquartile range). *, the P value reflects the difference between the ratio of thyroid nodules with a taller-than-wider shape only on transverse section and that on transverse or longitudinal section; †, the nodules were considered multifocal high-suspicion nodules if they were multiple and classified as 4A, 4B, 4C or 5 based on C-TIRADS. C-TIRADS, Chinese Thyroid Imaging Reporting and Data System.