How to read this calculator
Enter the measurements, or press Simulate to load a case from the reviewed validation catalog. The calculator then shows:
- Results: the ACR TI-RADS level, total points and maximum diameter.
- ACR TI-RADS level: the ACR TI-RADS level for the total points lights up in its status colour.
How ACR TI-RADS scores a nodule
ACR white paper: “When assessing a nodule, the reader selects one feature from each of the first four categories and all the features that apply from the final category and sums the points.”
ACR white paper: “Note that although it is possible for a nodule to be awarded zero points and hence be characterized as TR1, all other nodules merit at least two points because a nodule that has a mixed cystic and solid composition (one point) will also gain at least one more point for the echogenicity of its solid component.”
ACR white paper: “Nodules that are cystic or almost completely cystic merit no points because they are almost universally benign”. Cystic or almost completely cystic: other features are not scored (ACR TI-RADS). Spongiform: other features are not scored (ACR TI-RADS).
ACR TI-RADS Atlas: “Spongiform is a benign finding. If there is concern for irregular margins or suspicious echogenic foci, reconsider your choice of spongiform.”
ACR white paper: “In nodules with calcifications that cause strong acoustic shadowing that precludes or limits assessment of internal characteristics, particularly echogenicity and composition, it is best to assume that the nodule is solid and assign two points for composition and one point for echogenicity.”
ACR white paper, on punctate echogenic foci: “This category includes echogenic foci that are associated with small comet-tail artifacts in solid components, as distinguished from the large comet-tail artifacts described earlier”.
ACR white paper: “practitioners should exercise caution when reporting minimal ETE, particularly for otherwise benign-appearing nodules.” In this calculator, Extra-thyroidal extension (3 points) means definite invasion, not mere contact, abutment or contour bulging.
Points by feature
| Feature | Points | ACR definition |
|---|---|---|
| Composition | ||
| Cystic or almost completely cystic | 0 | Entirely or nearly entirely cystic Anechoic: Applies to cystic or almost completely cystic nodules. |
| Spongiform | 0 | Composed predominantly (>50%) of small cystic spaces. Do not add further points for other categories. |
| Mixed cystic and solid | 1 | Assign points for predominant solid component. |
| Solid or almost completely solid | 2 | Composed entirely or nearly entirely of soft tissue, with only a few tiny cystic spaces |
| Cannot be determined because of calcification | 2 | Assign 2 points if composition cannot be determined because of calcification. |
| Echogenicity | ||
| Anechoic | 0 | Applies to cystic or almost completely cystic nodules. |
| Hyperechoic or isoechoic | 1 | Compared to adjacent parenchyma. |
| Hypoechoic | 2 | Decreased echogenicity relative to thyroid tissue |
| Very hypoechoic | 3 | More hypoechoic than strap muscles. |
| Cannot be determined | 1 | Assign 1 point if echogenicity cannot be determined. |
| Shape | ||
| Wider-than-tall | 0 | |
| Taller-than-wide | 3 | |
| Margin | ||
| Smooth | 0 | Uninterrupted, well-defined, curvilinear edge typically forming a spherical or elliptical shape |
| Ill-defined | 0 | Border of the nodule is difficult to distinguish from thyroid parenchyma |
| Lobulated or irregular | 2 | Lobulated: Protrusions into adjacent tissue. Irregular: Jagged, spiculated, or sharp angles. |
| Extra-thyroidal extension | 3 | Nodule extends through the thyroid margin Extrathyroidal extension: Obvious invasion = malignancy. |
| Cannot be determined | 0 | Assign 0 points if margin cannot be determined. |
| Echogenic foci (choose all that apply) | ||
| None | 0 | |
| Large comet-tail artifacts | 0 | Large comet-tail artifacts: V-shaped, >1 mm, in cystic components. |
| Macrocalcifications | 1 | Cause acoustic shadowing. |
| Peripheral (rim) calcifications | 2 | Complete or incomplete along margin. |
| Punctate echogenic foci | 3 | May have small comet-tail artifacts. |
Decision steps
ACR white paper: “When assessing a nodule, the reader selects one feature from each of the first four categories and all the features that apply from the final category and sums the points.”
| Step | Criterion | Meaning |
|---|---|---|
| TR1 | 0 Points | Benign |
| TR2 | 2 Points | Not Suspicious |
| TR3 | 3 Points | Mildly Suspicious |
| TR4 | 4 to 6 Points | Moderately Suspicious |
| TR5 | 7 Points or More | Highly Suspicious |
Size thresholds and follow-up
ACR white paper: “Nodules should be measured in three axes: (1) maximum dimension on an axial image, (2) maximum dimension perpendicular to the previous measurement on the same image, and (3) maximum longitudinal dimension on a sagittal image” and “Measurements should also include the nodule’s halo, if present.”
The calculator compares the maximum diameter with the thresholds exactly as entered, without rounding: 1.45 cm is below 1.5 cm.
ACR white paper: “Imaging can stop at 5 years if there is no change in size”.
ACR defines significant growth as a ≥20% increase in at least two dimensions with a minimum 2 mm increase, or a ≥50% increase in volume; a higher TR level on follow-up calls for the next sonogram in one year (ACR white paper).
ACR advises following no more than four nodules with the highest point scores that warrant surveillance, and targeting no more than two nodules with the highest point totals that meet FNA criteria (ACR white paper). The calculator scores one nodule at a time.
With Extra-thyroidal extension selected, the result shows ACR's alert instead of a routine size threshold. This suppression is Radikulus policy; ACR's chart itself still scores extra-thyroidal extension and prints the same thresholds.
Threshold reference
| Level | Points | FNA | Follow | No FNA or follow-up | Follow-up timing |
|---|---|---|---|---|---|
| TR1 Benign | 0 Points | — | — | No FNA or follow-up | — |
| TR2 Not Suspicious | 2 Points | — | — | No FNA or follow-up | — |
| TR3 Mildly Suspicious | 3 Points | FNA if ≥ 2.5 cm | Follow if ≥ 1.5 cm | No FNA or follow-up if < 1.5 cm | ACR white paper: “For a TR3 lesion, follow-up imaging may be performed at 1, 3, and 5 years.” |
| TR4 Moderately Suspicious | 4 to 6 Points | FNA if ≥ 1.5 cm | Follow if ≥ 1 cm | No FNA or follow-up if < 1.0 cm | ACR white paper: “For a TR4 lesion, scans should be done at 1, 2, 3, and 5 years.” |
| TR5 Highly Suspicious | 7 Points or More | FNA if ≥ 1 cm | Follow if ≥ 0.5 cm* | No FNA or follow-up if < 0.5 cm | ACR white paper: “For a TR5 lesion, we recommend scans every year for up to 5 years.” |
*Refer to discussion of papillary microcarcinomas for 5-9 mm TR5 nodules.
Worked example
Neck ultrasound at initial presentation (Eisa 2025, Fig. 1, PMID 40384890): a 1.1 × 1.5 × 1.9 cm nodule, reported as “solid composition (2 points), hypoechoic echogenicity (2 points), wider-than-tall shape (0 points), smooth margin (0 points), and no echogenic foci (0 points)”. The maximum diameter is the largest of the three measurements, 1.9 cm.
| Item | Value |
|---|---|
| Composition | Solid or almost completely solid (2 points) |
| Echogenicity | Hypoechoic (2 points) |
| Shape | Wider-than-tall (0 points) |
| Margin | Smooth (0 points) |
| Echogenic foci (choose all that apply) | None (0 points) |
| ACR TI-RADS points | 4 |
| Maximum diameter | 1.9 cm |
| ACR TI-RADS level | TR4 Moderately Suspicious |
ACR TI-RADS: FNA if ≥ 1.5 cm
For adult thyroid nodules assessed on ultrasound. Prior biopsy, abnormal cervical nodes and other clinical circumstances can change management; see limitations.
This illustrates the calculation, not the reported patient’s management.
Papillary microcarcinomas
ACR white paper: “biopsy of 5- to 9-mm TR5 nodules may be appropriate under certain circumstances”. The determination to perform FNA will involve shared decision making between the referring physician and the patient.
What the levels mean
No descriptor is a pathological diagnosis; no risk percentage is implied by the label alone.
ACR white paper: “Partial analysis showed cancer risk levels of no more than 2% for TR1 and TR2 nodules, 5% for TR3 nodules, 5% to 20% for TR4 nodules, and at least 20% for TR5 nodules”. These are not individual probabilities.
Feature assignment can vary between readers and change the TR level (Hoang 2021).
Limitations
ACR white paper: “The committee did not address follow-up for previously sampled nodules.” ACR TI-RADS FAQ: “We give an ACR TI-RADS classification for previously-biopsied nodules, but say that management should be at least partially guided by the biopsy results, and don’t give a specific recommendation.”
ACR white paper: “any history of prior FNA or ethanol ablation should be sought, as these procedures may lead to a suspicious appearance at follow-up ultrasound”.
Suspicious cervical nodes and FDG-PET-positive thyroid nodules require assessment beyond this nodule score; see the ACR guidance (white paper, FAQ-111).
The categories are ultrasound features. A nodule first seen on CT or MRI can be scored on a dedicated thyroid ultrasound; for incidental thyroid nodules on CT, MRI and other imaging, see the ACR Incidental Thyroid Findings Committee white paper.
Other systems
EU-TIRADS, K-TIRADS and ATA use different sonographic categories and biopsy thresholds; this calculator uses ACR TI-RADS (ETA 2023, K-TIRADS 2021).
ATA 2015 Recommendation 8 recommends FNA at ≥1 cm for high/intermediate-suspicion patterns and ≥1.5 cm for low-suspicion patterns, and considers FNA at ≥2 cm for very-low-suspicion patterns, for which observation is also reasonable (ATA 2015, Recommendation 8).
The 2025 ATA guidelines for differentiated thyroid cancer do not replace ATA 2015 Recommendation 8 for initial nodule assessment, and the 2023 international lexicon (I-TIRADS, phase I) does not replace ACR TI-RADS points.
Frequently asked questions
How do you calculate an ACR TI-RADS score?
Choose one feature in each of the first four categories and every applicable echogenic-foci type, then add the points. Cystic or almost completely cystic and spongiform nodules stop at 0 points (TR1). See Points by feature.
What does TI-RADS 4 (TR4) mean?
TR4 is 4–6 points, labelled “Moderately Suspicious” by ACR TI-RADS. It describes ultrasound features, not a pathological diagnosis. See What the levels mean.
What size thyroid nodule needs a biopsy under ACR TI-RADS?
The ACR chart states: TR3, “FNA if ≥ 2.5 cm”; TR4, “FNA if ≥ 1.5 cm”; TR5, “FNA if ≥ 1 cm”. These are routine thresholds; see the threshold reference and limitations.
How often is a TI-RADS 3 nodule followed up?
For TR3 nodules in the follow-size range, ≥1.5 to <2.5 cm, the ACR white paper states: “For a TR3 lesion, follow-up imaging may be performed at 1, 3, and 5 years.” See Size thresholds and follow-up and Limitations.
What is the difference between ACR TI-RADS and EU-TIRADS?
ACR TI-RADS and EU-TIRADS use different sonographic categories and biopsy thresholds. This calculator uses ACR TI-RADS. See Other systems.
Can ACR TI-RADS be used in children?
This calculator presents ACR recommendations for adult thyroid nodules assessed on ultrasound. It does not provide pediatric management guidance. See Limitations.
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. doi:10.1016/j.jacr.2017.01.046. PMID 28372962.
- American College of Radiology Committee on TI-RADS™ (Thyroid). ACR TI-RADS Assessment Categories. Available at: https://edge.sitecorecloud.io/americancoldf5f-acrorgf92a-productioncb02-3650/media/ACR/Files/RADS/TI-RADS/TI-RADS-Assessment-Categories.pdf. American College of Radiology. Accessed on 3 November 2026.
- American College of Radiology Committee on TI-RADS™ (Thyroid). ACR TI-RADS Assessment Categories (Alternative Chart). Available at: https://edge.sitecorecloud.io/americancoldf5f-acrorgf92a-productioncb02-3650/media/ACR/Files/RADS/TI-RADS/TI-RADS-Assessment-Categories-Alternative-chart.pdf. American College of Radiology. Accessed on 3 November 2026.
- American College of Radiology. ACR Thyroid Imaging, Reporting and Data System Lexicon Directory (ACR TI-RADS Atlas). Available at: https://edge.sitecorecloud.io/americancoldf5f-acrorgf92a-productioncb02-3650/media/ACR/Files/RADS/TI-RADS/TI-RADS-Atlas.pdf. Accessed on 3 November 2026.
- American College of Radiology. TI-RADS (current release). Available at: https://www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/Reporting-and-Data-Systems/TI-RADS. Accessed on 3 November 2026.
- American College of Radiology RADS Support. ACR TI-RADS FAQ (FAQ-111 to FAQ-116). Available at: https://radssupport.acr.org/support/solutions/articles/11000071474-acr-ti-rads-faq. Accessed on 3 November 2026.
- Tessler FN, Middleton WD, Grant EG. Thyroid Imaging Reporting and Data System (TI-RADS): A User's Guide. Radiology 2018;287(1):29-36. doi:10.1148/radiol.2017171240. PMID 29558300.
- Hoang JK, Middleton WD, Tessler FN. Update on ACR TI-RADS: Successes, Challenges, and Future Directions, From the AJR Special Series on Radiology Reporting and Data Systems. AJR 2021;216(3):570-578. doi:10.2214/AJR.20.24608. PMID 33112199.
- Hoang JK, Langer JE, Middleton WD, et al. Managing incidental thyroid nodules detected on imaging: white paper of the ACR Incidental Thyroid Findings Committee. J Am Coll Radiol 2015;12(2):143-150. doi:10.1016/j.jacr.2014.09.038. PMID 25456025.
- Haugen BR, Alexander EK, Bible KC, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid 2016;26(1):1-133. doi:10.1089/thy.2015.0020. PMID 26462967.
- Durante C, Hegedüs L, Czarniecka A, et al. 2023 European Thyroid Association Clinical Practice Guidelines for thyroid nodule management. Eur Thyroid J 2023;12(5):e230067. PMC10448590.
- Ha EJ, Chung SR, Na DG, et al. 2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations. Korean J Radiol 2021;22(12):2094-2123. PMC8628155.
- Eisa N. Isolated Skin Metastasis From Papillary Thyroid Carcinoma: A Rare Presentation. JCEM Case Rep 2025;3(7):luaf106. doi:10.1210/jcemcr/luaf106. PMID 40384890.