Table 3.
Diagnostic performance of biopsy criteria by the modified K-TIRADS and five risk stratification systems in small nodules (≤2 cm) (n=2,385)
| Ultrasound risk stratification systems | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | LR+ | LR- | DOR | AUC | Reduction rate of unnecessary biopsies (%)a) |
|---|---|---|---|---|---|---|---|---|---|
| Modified K-TIRADS | 86.6 (344/397) | 67.6 (1,344/1,988) | 34.8 (344/988) | 96.2 (1,344/1,397) | 2.67 | 0.20 | 13.55 | 0.771 | 67.6 |
| [82.9-89.8] | [65.5-69.7] | [31.8-37.9] | [95.1-97.1] | [2.48-2.88] | [0.15-0.25] | [9.99-18.36] | [0.754-0.788] | [65.5-69.7] | |
| AACE/ACE/AME | 79.6 (316/397) | 66.6 (1,325/1,988) | 32.3 (316/979) | 94.2 (1,325/1,406) | 2.39 | 0.31 | 7.80 | 0.731 | 66.6 |
| [75.3-83.5] | [64.5-68.7] | [29.4-35.3] | [92.9-95.4] | [2.20-2.58] | [0.25-0.37] | [6.00-10.12] | [0.713-0.749] | [64.6-68.7] | |
| ACR TI-RADS | 76.1 (302/397) | 76.3 (1,517/1,988) | 39.1 (302/773) | 94.1 (1,517/1,612) | 3.21 | 0.31 | 10.24 | 0.762 | 76.3 |
| [71.6-80.2] | [74.4-78.2] | [35.6-42.6] | [92.8-95.2] | [2.92-3.54] | [0.26-0.37] | [7.95-13.18] | [0.744-0.779] | [74.4-78.2] | |
| ATA | 85.4 (339/397) | 55.2 (1,098/1,988) | 27.6 (339/1,229) | 95.0 (1,098/1,156) | 1.91 | 0.26 | 7.21 | 0.703 | 55.2 |
| [81.5-88.7] | [53.0-57.4] | [25.1-30.2] | [93.6-96.2] | [1.79-2.03] | [0.21-0.34] | [5.38-9.66] | [0.684-0.721] | [53.0-57.4] | |
| EU-TIRADS | 84.1 (334/397) | 54.2 (1,077/1,988) | 26.8 (334/1,245) | 94.5 (1,077/1,140) | 1.84 | 0.29 | 6.27 | 0.692 | 54.2 |
| [80.2-87.6] | [52.0-56.4] | [24.4-29.4] | [93.0-95.7] | [1.72-1.96] | [0.23-0.37] | [4.72-8.32] | [0.673-0.710] | [52.0-56.4] | |
| K-TIRADS | 96.2 (382/397) | 27.4 (544/1,988) | 20.9 (382/1,826) | 97.3 (544/559) | 1.32 | 0.14 | 9.59 | 0.618 | 27.4 |
| [93.8-97.9] | [25.4-29.4] | [19.1-22.9] | [95.6-98.5] | [1.28-1.37] | [0.08-0.23] | [5.67-16.22] | [0.598-0.637] | [25.4-29.4] |
Values in parentheses are number of nodules; values in square brackets are 95% confidence intervals.
K-TIRADS, Korean Thyroid Imaging Reporting and Data System; PPV, positive predictive value; NPV, negative predictive value; LR+, likelihood ratio for positive results; LR-, likelihood ratio for negative results; DOR, diagnostic odds ratio; AUC, area under the receiver operating characteristic curve; AACE/ACE/AME, American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi Medical Guidelines; ACR TI-RADS, American College of Radiology Thyroid Imaging Reporting and Data System; ATA, American Thyroid Association Management Guideline; EU-TIRADS, European Thyroid Imaging Reporting and Data System.
The reduction rate of unnecessary biopsies indicates the proportion of nodules not indicated for biopsy among all benign nodules.