Table 1.
Demographic and ultrasound characteristics of prospectively enrolled patients
| Characteristics | Training cohort (n =109) | Test cohort (n= 39) | P value | Validation cohort (n = 70) | P value |
|---|---|---|---|---|---|
| Lymph node metastasis | 0.64 | 0.67 | |||
| No. of metastases | 55 (50.5) | 18 (46.2) | 33 (47.1) | ||
| No. of no metastases | 54 (49.5) | 21 (53.8) | 37 (52.9) | ||
| Age, years (median ± SD) | 42.7 ± 11.7 | 40.7 ± 9.9 | 0.34 | 45.0 ± 11.6 | 0.20 |
| Gender | 0.16 | 0.16 | |||
| No. of males | 24 (22.0) | 13 (33.3) | 22 (31.4) | ||
| No. of females | 85 (78.0) | 26 (66.7) | 48 (68.6) | ||
| No. of tumors | 0.59 | 0.79 | |||
| 1 | 79 (72.5) | 30 (76.9) | 52 (74.3) | ||
| > 1 | 30 (27.5) | 9 (23.1) | 18 (25.7) | ||
| Tumor size, cm (median [IQR]) | 1.21 ± 0.73 | 1.20 ± 0.62 | 0.93 | 0.98 ± 0.66 | 0.03 |
| Location | 0.86 | 0.13 | |||
| Left lobe | 40 (36.7) | 15 (38.5) | 29 (41.4) | ||
| Right lobe | 40 (36.7) | 14 (35.9) | 31 (44.3) | ||
| Isthmus | 5 (4.6) | 3 (7.7) | 4 (5.7) | ||
| Bilateral | 24 (22.0) | 7 (17.9) | 6 (8.6) | ||
| Echogenicity | > 0.99 | 0.08 | |||
| Hypoechoic | 108 (99.1) | 39 (100.0) | 66 (94.3) | ||
| Iso/hyperechoic | 1 (0.9) | 0 (0) | 4 (5.7) | ||
| Margin | 0.29 | 0.06 | |||
| Clear | 32 (29.4) | 8 (20.5) | 12 (17.1) | ||
| Unclear | 77 (70.6) | 31 (79.5) | 58 (82.9) | ||
| Shape | |||||
| Regular | 9 (8.3) | 1 (2.6) | 0.29 | 6 (8.6) | 0.94 |
| Irregular | 100 (91.7) | 38 (97.4) | 64 (91.4) | ||
| Height-to-width ratio | 0.82 | < 0.001 | |||
| Taller than wide (> 1) | 47 (43.1) | 16 (41.0) | 51 (72.9) | ||
| Wider than tall (< 1) | 62 (56.9) | 23 (59.0) | 19 (27.1) | ||
| Calcification | 0.75 | 0.08 | |||
| No calcification | 26 (23.9) | 7 (17.9) | 13 (18.6) | ||
| Macro-calcification | 21 (19.3) | 8 (20.5) | 24 (34.3) | ||
| Micro-calcification | 62 (56.9) | 24 (61.5) | 33 (47.1) | ||
| US suspicious lymph node | 0.07 | 0.06 | |||
| No. of positives | 43 (39.4) | 9 (23.1) | 18 (25.7) | ||
| No. of negatives | 66 (60.6) | 30 (76.9) | 52 (74.3) | ||
| Hashimoto thyroiditis | 0.49 | 0.49 | |||
| No. of negatives | 93 (85.3) | 35 (89.7) | 57 (81.4) | ||
| No. of positives | 16 (14.7) | 4 (10.3) | 13 (18.6) | ||
| Clinical T stage | 0.43 | 0.38 | |||
| T1 | 102 (93.6) | 35 (89.7) | 63 (90.0) | ||
| T2–T3 | 7 (6.4) | 4 (10.3) | 7 (10.0) | ||
| Clinical N stage | 0.26 | 0.07 | |||
| N0 | 63 (57.8) | 26 (66.7) | 49 (70.0) | ||
| N1a | 12 (11.0) | 1 (2.6) | 10 (14.3) | ||
| N1b | 34 (31.2) | 12 (30.8) | 11 (15.7) | ||
| Pathological T stage | 0.31 | 0.95 | |||
| T1 | 103 (94.5) | 35 (89.7) | 66 (94.3) | ||
| T2–T3 | 6 (5.5) | 4 (10.3) | 4 (5.7) | ||
| Type of thyroidectomy | 0.89 | 0.07 | |||
| Lobectomy | 24 (22.0) | 9 (23.1) | 24 (48.6) | ||
| Total thyroidectomy | 85 (78.0) | 30 (76.9) | 46 (51.4) | ||
| Type of lymph node dissection | 0.75 | 0.27 | |||
| CLND | 81 (74.3) | 30 (76.9) | 57 (81.4) | ||
| CLND + LLND | 28 (25.7) | 9 (23.1) | 13 (18.6) | ||
Unless otherwise specified, data in parentheses are percentages. SD, standard deviation; CLND, central lymph node dissection; LLND, lateral lymph node dissection