How this instrument works
The ACR Thyroid Imaging, Reporting and Data System comes from a 2017 white paper by Tessler, Middleton, Grant, and the ACR TI-RADS Committee, published in the Journal of the American College of Radiology. It follows the same logic as BI-RADS for mammography: describe what is seen on the image using a fixed vocabulary, convert that description into points, and use the points to sort the finding into a small number of risk categories that different radiologists will reach consistently.
Five features are scored independently. Composition runs 0 to 2 points, from cystic or spongiform up to solid. Echogenicity runs 0 to 3, from anechoic up to very hypoechoic. Shape is scored 0 for wider-than-tall or 3 for taller-than-wide, with no points in between. Margin runs 0 to 3, from smooth or ill-defined up to extra-thyroidal extension. Echogenic foci run 0 to 3, from none or large comet-tail artifacts up to punctate echogenic foci. The five scores are added into one points total.
That total maps onto five tiers: 0 points is TR1, 1 to 2 points is TR2, exactly 3 points is TR3, 4 to 6 points is TR4, and 7 or more is TR5. The system deliberately separates two questions that are easy to conflate — how suspicious does this nodule look, which is what the points measure, and what should be done about it, which the TR level only partly answers. The full ACR TI-RADS system pairs the TR level with the nodule's size on a separate lookup table, not reproduced in this calculator, to decide between fine-needle aspiration biopsy, follow-up ultrasound, or no further action.
That last step matters because TR level alone is not a management decision. A TR5 nodule under about 1 cm and a TR3 nodule several centimetres across can call for different next steps once size is factored in — the points and category from this calculator are one half of the ACR's actual recommendation, and should be read alongside the nodule's measured diameter, not in place of it.
- Set Composition (cystic/spongiform, mixed, or solid).
- Set Echogenicity (anechoic, hyper/isoechoic, hypoechoic, or very hypoechoic).
- Set Shape (wider than tall, or taller than wide) and Margin (smooth/ill-defined, lobulated/irregular, or extra-thyroidal).
- Set Echogenic foci (none/comet-tail, macrocalcifications, peripheral, or punctate).
- Read the total points and the resulting TR level (TR1 through TR5).
Worked example — solid, hypoechoic, irregular margin, macrocalcification
A nodule described as solid (2 points), hypoechoic (2 points), wider than tall (0 points), with lobulated or irregular margins (2 points) and a macrocalcification (1 point). Summed: 2 + 2 + 0 + 2 + 1 = 7 points. Because 7 is at or above the 7-point threshold, this nodule lands in TR5, the ACR system's highest-suspicion category, where even a relatively small nodule can meet the size threshold for biopsy on the accompanying size table.
Strip every suspicious feature away and the same five categories score 0 across the board — purely cystic or spongiform, with no worrying echogenicity, shape, margin, or calcification — for a total of 0 points and TR1, the lowest category, for which the ACR system recommends no biopsy regardless of size. A solid nodule that is otherwise unremarkable, with hyper- or isoechoic echogenicity and nothing concerning about its shape, margin, or calcifications, scores 2 + 1 + 0 + 0 + 0 = 3 points, landing in TR3 — mildly suspicious, where biopsy is recommended only once the nodule reaches a larger size on the accompanying table.
Questions
Does a high TI-RADS points total by itself mean a nodule needs a biopsy?
No. The points total only produces a TR level (TR1 through TR5), and the ACR TI-RADS system's actual biopsy recommendation combines that TR level with the nodule's measured size on a separate lookup table this calculator does not include. A TR5 nodule under roughly 1 cm may only need follow-up ultrasound, while a TR3 nodule several centimetres across can meet the threshold for biopsy — level and size have to be read together, not the level alone.
What is the practical difference between TR4 and TR5?
TR4 covers totals of 4 to 6 points, TR5 covers totals of 7 or more — a single point can move a nodule from one category to the other. Swapping a macrocalcification (1 point) for punctate echogenic foci (3 points) on an otherwise identical nodule, for example, adds 2 points and can be exactly the difference between a TR4 and a TR5 read, with different size thresholds attached to each on the accompanying biopsy table.
Why do some categories score up to 3 points and shape only scores 0 or 3?
The point ranges reflect how strongly each feature predicted malignancy in the data behind the white paper. Composition, echogenicity, margin, and echogenic foci each show a graded relationship with risk, so they carry a spread of point values. Shape's taller-than-wide appearance was found to behave more like a binary flag than a gradient — a nodule either shows that growth pattern or it doesn't — so it is scored as all 3 points or none, with no intermediate value.
Can TI-RADS points be assigned from a CT or MRI scan instead of ultrasound?
No. Every category in ACR TI-RADS — composition, echogenicity, shape, margin, and echogenic foci — describes an ultrasound appearance specifically, and the point values were derived from ultrasound-based studies. A nodule described only on CT or MRI cannot be scored with this system without a dedicated ultrasound to characterize it using the ACR's standardized lexicon.
Who decides the point value for each category?
The radiologist reading the ultrasound images assigns each of the five scores, using the ACR's standardized lexicon of terms for composition, echogenicity, shape, margin, and echogenic foci. Because some features, especially margin and echogenic foci, involve judgment calls on borderline images, inter-reader agreement is good but not perfect, and a second radiologist reviewing the same images can occasionally land on an adjacent TR level.
What happens to a nodule with more than one type of echogenic focus?
The echogenic foci category takes the single highest-scoring feature present rather than adding multiple types together — a nodule with both macrocalcifications (1 point) and punctate echogenic foci (3 points) is scored 3 for that category, not 4. The same highest-value rule is why the category tops out at 3 points regardless of how many concerning focus types appear.
References
- Tessler et al. 2017, J Am Coll Radiol — ACR TI-RADS white paper (PubMed)
- American College of Radiology — official ACR TI-RADS resource page
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.