Table 4.
Sensitivity, specificity, PPV, NPV, and hypothetical percentage of spared FNA, grouping comparable ultrasound score classes
| Risk class (expected malignancy risk) | US score classes | Sensitivity (CI 95%) | Specificity (CI 95%) | PPV (CI 95%) | NPV (CI 95%) | % spared FNA |
|---|---|---|---|---|---|---|
| Low-risk classes, < 5% | KTIRADS 2 | 57.9% (± 5.6%; 52.3–63.5%) | 44.3% (± 1.6%; 42.7–45.9%) | 7.3% (± 1.0%; 6.3–8.3%) | 93.3% (± 1.1%; 92.2–94.4%) | 44.2% |
| ATA benign–very low risk | ||||||
| AACE low | ||||||
| EUTIRADS 2–3 | ||||||
| ACRTIRADS 1–2 | ||||||
| Intermediate-risk classes, 5–20% | KTIRADS3 | 75.3% (± 2.0%; 73.3–77.3%) | 27.2% (± 0.7%; 26.5–27.9%) | 8.7% (± 0.4%; 8.3–9.1%) | 92.2% (± 0.7%; 91.5–92.9%) | 26.9% |
| ATA low–intermediate | ||||||
| AACE intermediate | ||||||
| EUTIRADS 4 | ||||||
| ACRTIRADS 3–4 | ||||||
| High-risk classes, > 20% | KTIRADS 4–5 | 98.1% (± 0.7%; 97.4–98.8%) | 0.9% (± 0.2%; 0.7–1.1%) | 15.7% (± 0.7%; 15.0–16.4%) | 72.5% (± 2.4%; 70.1–74.9%) | 1.1% |
| ATA high | ||||||
| AACE high | ||||||
| EUTIRADS 5 | ||||||
| ACRTIRADS 5 |