How the TI-RADS System Works: Understanding Thyroid Nodule Scoring
Keywords: how TI-RADS works, ACR TI-RADS explained, TI-RADS thyroid ultrasound, TI-RADS scoring system, thyroid nodule risk classification, ACR TI-RADS calculator
What Is TI-RADS?
The Thyroid Imaging Reporting and Data System (TI-RADS) is a standardized method developed by the American College of Radiology (ACR) to classify thyroid nodules found on ultrasound.
Its goal is simple: make thyroid nodule reporting consistent, evidence-based, and easy to interpret across sonographers, radiologists, and referring clinicians.
Instead of vague terms like “slightly suspicious” or “needs follow-up,” TI-RADS assigns points to specific ultrasound features. These points add up to a category (TR1–TR5) that reflects the likelihood of malignancy and helps determine whether fine-needle aspiration (FNA) or follow-up imaging is recommended.
If you’d like to review the official source, you can read the
👉 ACR TI-RADS guidelines on Radiopaedia
for full scoring tables and management recommendations.
The Five Key Features of TI-RADS
The ACR system evaluates five ultrasound features, each worth a certain number of points:
Composition: Cystic (0), Spongiform (0), Mixed (1), Solid (2)
Echogenicity: Anechoic (0), Hyperechoic/Isoechoic (1), Hypoechoic (2), Very Hypoechoic (3)
Shape: Wider than tall (0), Taller than wide (3)
Margin: Smooth (0), Ill-defined (0), Lobulated/Irregular (2), Extrathyroidal extension (3)
Echogenic Foci: None (0), Large comet tail (0), Macrocalcifications (1), Peripheral/rim calcifications (2), Punctate echogenic foci (3)
Each selected option contributes to the total score.
TI-RADS Categories and What They Mean
TR1 – Benign (0 points)
Likelihood of malignancy: ~0%
Recommendation: No FNA or follow-up.
TR2 – Not Suspicious (2 points)
Likelihood of malignancy: ~1.5%
Recommendation: No FNA or follow-up.
TR3 – Mildly Suspicious (3 points)
Likelihood of malignancy: ~4.8%
Recommendation: Follow-up ≥1.5 cm; FNA ≥2.5 cm.
TR4 – Moderately Suspicious (4–6 points)
Likelihood of malignancy: ~9.1%
Recommendation: Follow-up ≥1.0 cm; FNA ≥1.5 cm.
TR5 – Highly Suspicious (≥7 points)
Likelihood of malignancy: ~35%
Recommendation: Follow-up ≥0.5 cm; FNA ≥1.0 cm.
These thresholds are based on the ACR TI-RADS guidelines and can help reduce unnecessary biopsies while ensuring significant nodules are properly investigated.
Why TI-RADS Is Important
Before TI-RADS, thyroid ultrasound reports varied dramatically between practitioners.
Now, using TI-RADS:
Sonographers and radiologists speak a common language.
Patients receive clear, evidence-based follow-up recommendations.
Clinics minimize over-biopsy and streamline workflows.
This consistency improves communication with referring physicians and ultimately leads to better patient outcomes.
How to Apply It in Practice
When performing a thyroid ultrasound:
Identify and document each nodule’s five core features.
Use the TI-RADS Calculator to assign points and automatically determine the category.
Include the category (e.g., TR4) and recommended action in your report.
For follow-up, note the time interval (e.g., TR3 nodules > 1.5 cm → repeat at 1, 3, and 5 years).
Over time, applying TI-RADS consistently will sharpen your diagnostic accuracy and help you build stronger clinical confidence.
Want to Calculate a Score Instantly?
👉 Try the ACR TI-RADS Calculator — a free, easy-to-use tool built by a fellow sonographer to simplify your thyroid reporting workflow.
