Table 3.
US features of the nodules according to the reference standard diagnosis
| US feature | Total (n = 942) | Benign nodules (n = 839) | Malignant nodules (n = 103) | Positive LR (95% CI) | Negative LR (95% CI) | p value |
|---|---|---|---|---|---|---|
| Echogenicity | ||||||
| Anechoic* | 8 (0.8) | 8 (1.0) | 0 (0) | NA | 0.99 (0.9–1.0) | 1.000 |
| Hyperechoic/isoechoic* | 418 (44.4) | 417 (49.7) | 1 (1.0) | 51.2 (7.3–360.4) | 0.51 (0.5–0.6) | <0.001 |
| Mildly hypoechoic† | 357 (37.9) | 320 (38.1) | 37 (35.9) | 0.94 (0.7–1.2) | 1.04 (0.9–1.2) | 0.661 |
| Markedly hypoechoic† | 159 (16.9) | 94 (11.2) | 65 (63.1) | 5.63 (4.4–7.2) | 0.42 (0.3–0.5) | <0.001 |
| Composition | ||||||
| Solid† | 681 (72.3) | 584 (69.6) | 97 (94.2) | 1.35 (1.3–1.4) | 0.19 (0.1–0.4) | <0.001 |
| Mixed cystic and solid* | 216 (22.9) | 210 (25.0) | 6 (5.8) | 4.30 (2.0–9.4) | 0.80 (0.8–0.9) | <0.001 |
| Cystic* | 8 (0.8) | 8 (1.0) | 0 (0) | NA | 0.99 (0.9–1.0) | 1.000 |
| Spongiform* | 37 (4.0) | 37 (4.4) | 0 (0) | NA | 0.96 (0.9–1.0) | 0.027 |
| Echotexture | ||||||
| Homogeneous† | 685 (72.7) | 602 (71.8) | 83 (80.6) | 1.12 (1.0–1.3) | 0.69 (0.5–1.0) | 0.058 |
| Heterogeneous* | 257 (27.3) | 237 (28.2) | 20 (19.4) | 1.45 (1.0–2.2) | 0.89 (0.8–1.0) | 0.058 |
| Calcifications | ||||||
| Micro† | 118 (12.5) | 53 (6.3) | 65 (63.1) | 9.99 (7.4–13.5) | 0.39 (0.3–0.5) | <0.001 |
| Macro or eggshell* | 118 (12.5) | 112 (13.4) | 6 (5.8) | 2.29 (1.0–5.1) | 0.92 (0.9–1.0) | 0.029 |
| None* | 706 (75.0) | 674 (80.3) | 32 (31.1) | 2.59 (1.9–3.5) | 0.29 (0.2–0.3) | <0.001 |
| Margins | ||||||
| Smooth* | 812 (86.2) | 775 (92.4) | 37 (35.9) | 2.57 (2.0–3.3) | 0.12 (0.1–0.2) | <0.001 |
| Irregular† | 130 (13.8) | 64 (7.6) | 66 (64.1) | 8.40 (6.4–11.1) | 0.39 (0.3–0.5) | <0.001 |
| Shape | ||||||
| Oval* | 814 (86.4) | 764 (91.1) | 50 (48.5) | 1.88 (1.5–2.3) | 0.17 (0.1–0.2) | <0.001 |
| Non-oval† | 128 (13.6) | 75 (8.9) | 53 (51.5) | 5.76 (4.3–7.7) | 0.53 (0.4–0.7) | <0.001 |
| Vascularity | ||||||
| Type I/II* | 813 (86.3) | 747 (89.0) | 66 (64.1) | 1.39 (1.2–1.6) | 0.31 (0.2–0.4) | <0.001 |
| Type III† | 129 (13.7) | 92 (11.0) | 37 (35.9) | 3.28 (2.4–4.5) | 0.72 (0.6–0.8) | <0.001 |
Data in parentheses are percentages. p values are calculated using χ2 test and Fisher's exact test. Positive likelihood ratio (LR) = sensitivity/1 − specificity; negative LR = 1 − sensitivity/specificity. Oval shape = oval or round shape; non-oval shape = taller-than-wide or taller-than-long shape.
Diagnostic parameters of the US features to predict malignant nodules: the presence of the US feature in a malignant nodule was considered true positive case and the absence in a benign nodule, true negative case when sensitivity and specificity were calculated.
Diagnostic parameters of the US features to predict benign nodules: the presence of the US feature in a benign nodule was considered true positive case and the absence in a malignant nodule, true negative case when sensitivity and specificity were calculated. US, ultrasound; NA, not applicable.