ACR TI-RADS thyroid nodule calculator
Score a thyroid nodule with the ACR TI-RADS 2017 system. Choose the ultrasound features, add the size, and get the TR level, the FNA and follow-up thresholds, and a report line you can paste straight into your findings.
Compare with a prior study
Enter the prior measurements in the same order. The check applies the ACR growth rule: a 20% and 2 mm increase in at least two dimensions, or a 50% volume increase (all three dimensions needed for volume).
Report line
How ACR TI-RADS 2017 works
TI-RADS adds points across five ultrasound features. The total decides the risk level and whether fine-needle aspiration (FNA) or follow-up ultrasound is advised, based on the nodule's largest diameter.
| Level | Points | Est. malignancy | FNA | Follow-up US |
|---|---|---|---|---|
| TR1 | 0 | 0.3% | None | None |
| TR2 | 1–2 | 1.5% | None | None |
| TR3 | 3 | 4.8% | ≥2.5 cm | ≥1.5 cm (1, 3, 5 yr) |
| TR4 | 4–6 | 9.1% | ≥1.5 cm | ≥1.0 cm (1, 2, 3, 5 yr) |
| TR5 | ≥7 | ≥35% | ≥1.0 cm | ≥0.5 cm (annually to 5 yr) |
Chart notes the calculator applies: a spongiform nodule takes no further points; composition that cannot be determined because of calcification scores 2, echogenicity that cannot be determined scores 1, and a margin that cannot be determined scores 0. Mixed cystic and solid nodules are scored on the solid component.
Source: Tessler FN et al., ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee, J Am Coll Radiol 2017;14:587–595. ACR has not replaced the 2017 system.
Worked example: a follow-up scan
A synthetic case. A right mid pole nodule is solid (2), hypoechoic (2), wider-than-tall (0), with a smooth margin (0) and no echogenic foci (0). That is 4 points, TR4. It measures 14 × 10 × 9 mm. The largest diameter, 1.4 cm, is above the 1.0 cm follow-up threshold and below the 1.5 cm FNA threshold, so follow-up ultrasound is advised.
The prior study measured 11 × 8 × 7 mm. The transverse dimension grew 3 mm (27%), AP 2 mm (25%) and longitudinal 2 mm (29%), so all three meet the 20% and 2 mm rule. The ellipsoid volume roughly doubled (+105%). This is significant enlargement. The nodule still sits below the TR4 FNA threshold, so follow-up continues. If it had been TR3 on the prior study, the level increase alone means the next sonogram is due in 1 year.
Questions radiologists ask
How do you score a feature that cannot be determined?
The ACR chart assigns 2 points when composition cannot be determined because of calcification, 1 point when echogenicity cannot be determined, and 0 points when the margin cannot be determined.
Do spongiform nodules get points for other features?
No. A spongiform nodule is composed predominantly (more than 50%) of small cystic spaces. The ACR chart says to add no further points for other categories, so it scores 0 points, TR1. Small echogenic foci in a spongiform nodule are not suspicious.
What counts as significant thyroid nodule growth under ACR TI-RADS?
A 20% increase in at least two nodule dimensions with a minimal increase of 2 mm, or a 50% or greater increase in volume. The new size then decides management for the nodule's TR level. If the TR level increases, the next sonogram should be in 1 year, regardless of the initial level. Compare with earlier scans too, because slow growth can hide between consecutive studies.
When can thyroid nodule follow-up stop?
Imaging can stop at 5 years if there is no change in size. Follow-up intervals are 1, 3 and 5 years for TR3, 1, 2, 3 and 5 years for TR4, and every year for up to 5 years for TR5.
How many thyroid nodules should be biopsied or followed?
ACR recommends FNA of no more than two nodules, chosen by the highest point totals rather than size, and formal follow-up of no more than four nodules that fall below the FNA size threshold.
What about a 5–9 mm TR5 nodule?
ACR advises against routine FNA below 1 cm. FNA may still be appropriate after shared decision-making, so the report should say whether the nodule can be measured reproducibly and whether it abuts the trachea or the tracheoesophageal groove.
Is the TI-RADS calculator a diagnostic device?
No. It is decision-support software that reproduces the published ACR TI-RADS rules. It does not store patient data. Always confirm the result and apply clinical judgement before reporting.