ACR TI-RADS Calculator — Thyroid Nodule Risk Stratification
The American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) is a standardized classification system for thyroid nodules based on ultrasound features. It assigns points for composition, echogenicity, shape, margin, and echogenic foci to stratify malignancy risk and guide FNA decisions.
About
The American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) was introduced in 2017 to standardize the reporting of thyroid nodules on ultrasound and provide evidence-based recommendations for fine-needle aspiration (FNA) biopsy. The system assigns points across five ultrasound feature categories: composition (cystic/spongiform, mixed cystic-solid, solid), echogenicity (anechoic, isoechoic, hypoechoic, very hypoechoic), shape (wider-than-tall, taller-than-wide), margin (smooth, ill-defined, lobulated/irregular, extrathyroidal extension), and echogenic foci (none, large comet-tail, macrocalcifications, peripheral/rim calcifications, punctate echogenic foci). The total points determine the TI-RADS level from TR1 (benign, 0-1 points) to TR5 (highly suspicious, 7+ points). The TR level then guides FNA recommendations based on nodule size: TR3 (≥2.5 cm), TR4 (≥1.5 cm), TR5 (≥1.0 cm). TR1 and TR2 do not require FNA. The ACR TI-RADS system has been validated extensively with high inter-observer agreement and malignancy risk stratification: TR1 (<2%), TR2 (<2%), TR3 (5-10%), TR4 (10-20%), TR5 (>20%). The system reduces unnecessary FNA procedures by 40-60% compared to alternative classification systems while maintaining high sensitivity for detecting clinically significant thyroid cancers. ACR TI-RADS is endorsed by the American College of Radiology, the American Thyroid Association (ATA), and the European Thyroid Association.
Formula
Total Points = Composition + Echogenicity + Shape + Margin + Echogenic Foci. TR1 (0-1): Benign. TR2 (2): Not suspicious. TR3 (3): Mildly suspicious. TR4 (4-6): Moderately suspicious. TR5 (7+): Highly suspicious.
The TI-RADS score is calculated by summing points from five ultrasound feature categories. Composition: cystic/spongiform (0), mixed cystic-solid (1), solid (2). Echogenicity: anechoic (0), isoechoic (1), hypoechoic (2), very hypoechoic (3). Shape: wider-than-tall (0), taller-than-wide (3). Margin: smooth/ill-defined (0), lobulated/irregular (2), extrathyroidal extension (3). Echogenic foci: none/large comet-tail (0), macrocalcifications (1), peripheral/rim (2), punctate (3). Total score determines the TR level and corresponding FNA size threshold.
Score Interpretation
ACR TI-RADS has transformed the management of thyroid nodules by providing a standardized, evidence-based approach to risk stratification. Its clinical significance lies in reducing unnecessary FNA procedures by 40-60% compared to earlier classification systems (e.g., ATA guidelines) while maintaining high sensitivity for clinically significant thyroid cancers (>95% for cancers >1 cm). The system improves inter-observer agreement compared to non-standardized reporting and provides clear, actionable recommendations. ACR TI-RADS is now the most widely used thyroid nodule classification system in the United States and is increasingly adopted internationally.
TR1 — Benign — 0–1
TI-RADS 0-1. Benign nodule. Malignancy risk <2%. No FNA indicated.
Management: No FNA. Routine follow-up per clinical guidelines. Reassess if nodule grows >50% volume or new suspicious features develop.
TR2 — Not Suspicious — 2–2
TI-RADS 2. Not suspicious. Malignancy risk <2%. No FNA indicated.
Management: No FNA. Routine follow-up. Reassess if nodule grows >50% volume.
TR3 — Mildly Suspicious — 3–3
TI-RADS 3. Mildly suspicious. Malignancy risk 5-10%. FNA if nodule ≥2.5 cm.
Management: FNA if nodule ≥2.5 cm. Follow-up in 1, 3, and 5 years if no FNA performed. Consider ultrasound surveillance.
TR4 — Moderately Suspicious — 4–6
TI-RADS 4-6. Moderately suspicious. Malignancy risk 10-20%. FNA if nodule ≥1.5 cm.
Management: FNA if nodule ≥1.5 cm. Follow-up in 1, 2, 3, and 5 years if no FNA performed.
TR5 — Highly Suspicious — 7+
TI-RADS 7+. Highly suspicious for malignancy. Malignancy risk >20%. FNA if nodule ≥1.0 cm.
Management: FNA if nodule ≥1.0 cm. Consider diagnostic lobectomy if high clinical suspicion even with negative FNA.
Reference Ranges
| Population | Normal Range | Notes |
|---|---|---|
| Adults with thyroid nodules on ultrasound | TR1 (0-1 points) to TR5 (7+ points) | Higher TR level = higher malignancy risk. TR1-2: <2%, TR3: 5-10%, TR4: 10-20%, TR5: >20% |
Dr. Khaled Hassan
Dr. Khaled is a cardiology consultant with experience in acute cardiac care.
View medical review board & editorial policy →Example Calculation
A 45-year-old woman presents with a 2.8 cm thyroid nodule found incidentally on carotid ultrasound. Dedicated thyroid ultrasound shows: a solid nodule (2 points), hypoechoic (2 points), wider-than-tall (0 points), smooth margins (0 points), with punctate echogenic foci (3 points). Total TI-RADS score = 2+2+0+0+3 = 7 points = TR5 (Highly suspicious). Malignancy risk >20%. FNA is recommended since the nodule is ≥1.0 cm. The patient undergoes FNA which shows Bethesda Category V (suspicious for malignancy). Consult endocrine surgery for lobectomy.
Related Conditions
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Common Mistakes
Using TI-RADS for nodules <1 cm without considering clinical risk factors
ACR TI-RADS is designed for nodules ≥1 cm. For nodules <1 cm, FNA is generally not recommended unless there is high-risk clinical context (family history of thyroid cancer, prior radiation, suspicious lymphadenopathy, or concerning features on ultrasound). TI-RADS can still be reported for nodules <1 cm but FNA thresholds should not be applied rigidly.
Assigning points for multiple echogenic foci types in the same nodule
In ACR TI-RADS, only the HIGHEST-scoring echogenic foci feature is counted, not the sum of multiple types. For example, if a nodule has both macrocalcifications (1 point) and punctate echogenic foci (3 points), assign only 3 points for punctate foci, not 4. The highest-risk feature takes precedence.
Substituting TI-RADS for cytological or histological diagnosis
TI-RADS is a risk stratification tool, not a diagnostic test. It guides the decision to perform FNA but cannot replace cytological diagnosis (Bethesda classification) or histological confirmation. Even TR5 nodules have a 20-30% chance of being benign at surgical pathology.
Frequently Asked Questions
What is the malignancy risk for each TI-RADS level?
What is the recommended follow-up for TI-RADS categories?
How does ACR TI-RADS compare to ATA Guidelines for thyroid nodules?
References
- Tessler FN, Middleton WD, Grant EG, 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. PubMed
- Middleton WD, Teefey SA, Reading CC, 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. PubMed
- Grant EG, Tessler FN, Hoang JK, 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. PubMed