ACR TI-RADS Calculator
Thyroid nodule ultrasound risk stratification based on ACR TI-RADS 2017 guidelines
What is ACR TI-RADS?
The American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) is an evidence-based, standardized risk stratification system for thyroid nodules detected on ultrasound. Published in 2017, it helps radiologists communicate nodule findings consistently and guides clinical decisions about fine-needle aspiration (FNA) biopsy.
How TI-RADS Scoring Works
Points are assigned based on five ultrasound feature categories. The total determines the TI-RADS level (TR1-TR5) and corresponding malignancy risk:
| Category | Points | Suspicion Level | Malignancy Risk |
|---|---|---|---|
| TR1 | 0 | Benign | ≤0.3% |
| TR2 | 2 | Not suspicious | ≤1.5% |
| TR3 | 3 | Mildly suspicious | ≤4.8% |
| TR4 | 4-6 | Moderately suspicious | ≤9.1% |
| TR5 | ≥7 | Highly suspicious | ≤35% |
FNA Recommendations by Category
FNA recommendations depend on both TI-RADS category and nodule size:
- TR1 & TR2: No FNA recommended regardless of size
- TR3: FNA if ≥2.5 cm; follow-up if ≥1.5 cm
- TR4: FNA if ≥1.5 cm; follow-up if ≥1.0 cm
- TR5: FNA if ≥1.0 cm; follow-up if ≥0.5 cm
Key Features to Assess
- Composition: Cystic, spongiform, mixed, or solid
- Echogenicity: Anechoic to very hypoechoic
- Shape: Wider-than-tall (benign) vs. taller-than-wide (suspicious)
- Margin: Smooth, ill-defined, lobulated, or extra-thyroidal
- Echogenic foci: Comet-tail, macro/peripheral calcifications, or punctate foci
References
Tessler FN, Middleton WD, Grant EG, Hoang JK, Berland LL, Teefey SA, 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(5):587-595. doi:10.1016/j.jacr.2017.01.046 PMID: 28372962
Grant EG, Tessler FN, Hoang JK, Langer JE, Beland MD, Berland LL, et al. Thyroid Ultrasound Reporting Lexicon: White Paper of the ACR Thyroid Imaging, Reporting and Data System (TIRADS) Committee. J Am Coll Radiol. 2015;12(12 Pt A):1272-1279. doi:10.1016/j.jacr.2015.07.011 PMID: 26419308
Middleton WD, Teefey SA, Reading CC, Langer JE, Beland MD, Szabunio MM, et al. Multiinstitutional Analysis of Thyroid Nodule Risk Stratification Using the American College of Radiology Thyroid Imaging Reporting and Data System. AJR Am J Roentgenol. 2017;208(6):1331-1341. doi:10.2214/AJR.16.17613 PMID: 28267342