Purpose of ACR TI-RADS

The American College of Radiology Thyroid Imaging Reporting and Data System standardises ultrasound description and risk stratification of thyroid nodules. It assigns points to composition, echogenicity, shape, margins and echogenic foci, then combines category with size thresholds to guide biopsy or follow-up discussions.

It is not a home screening test and cannot determine whether a nodule is cancer. A trained sonographer or radiologist must obtain and interpret images in multiple planes. This calculator is suitable for checking arithmetic from documented features, not for labelling a photograph or feeling a neck lump.

Composition points

Cystic or almost completely cystic and spongiform nodules receive zero composition points. Mixed cystic and solid nodules receive one, and solid or almost completely solid nodules receive two. Classification depends on the actual ultrasound appearance, not how firm a lump feels.

If composition cannot be determined because of calcification or image limitations, the official lexicon and professional judgement must be used. The dropdown does not include an indeterminate shortcut because assigning zero would falsely lower the score.

Echogenicity points

Anechoic receives zero, hyperechoic or isoechoic receives one, hypoechoic receives two and very hypoechoic receives three. Echogenicity is assessed relative to surrounding thyroid tissue and, for very hypoechoic findings, the neck musculature under the ACR definitions.

Display settings, artefact, thyroid heterogeneity and experience affect interpretation. A text label copied from a non-ACR report may not map perfectly. Use the reporting radiologist’s ACR feature choice where available rather than translating unfamiliar terminology unaided.

Shape and margin points

Wider-than-tall shape receives zero and taller-than-wide receives three, assessed on the transverse image. Smooth or ill-defined margins receive zero, lobulated or irregular margins two and extra-thyroidal extension three. Ill-defined is not the same as irregular in this scoring system.

Extra-thyroidal extension is a high-consequence feature that should not be selected from uncertainty. It requires professional interpretation and can influence management beyond the web result. Suspicious lymph nodes and invasion concerns also require direct clinical action rather than only nodule arithmetic.

Echogenic foci can add

Macrocalcifications add one point, peripheral or rim calcifications add two and punctate echogenic foci add three. Unlike a single-choice feature, more than one type of echogenic focus can be present, so the interface provides separate yes-or-no selections and adds their points.

Large comet-tail artefacts associated with colloid do not add points under the chart. Distinguishing punctate foci from benign artefact is an imaging task. Selecting every focus option merely because a report says calcification can over-score the nodule.

Category boundaries

Zero points is TR1. One or two points are TR2. Three is TR3, four through six are TR4 and seven or more are TR5. The category indicates increasing suspicion under this system but is not a percentage diagnosis for an individual.

A higher category does not mean immediate surgery, and a lower category does not explain symptoms. Cytology, molecular tests and surgical decisions use additional systems and evidence. Preserve the category label with the ultrasound date and nodule identifier because a thyroid can contain several different nodules.

Size thresholds

For TR3, ACR thresholds are follow-up at 1.5 cm and FNA at 2.5 cm. For TR4, they are 1.0 cm and 1.5 cm. For TR5, they are 0.5 cm and 1.0 cm. TR1 and TR2 do not receive routine FNA or follow-up from the point/size chart.

These are management guidance thresholds, not proof that a smaller nodule is harmless or a larger nodule malignant. Maximum diameter must come from the official ultrasound measurement. Entering millimetres as centimetres creates a tenfold error, so convert 12 mm to 1.2 cm.

Context can override a simple output

Clinical decisions can change with suspicious lymph nodes, compressive symptoms, radiation history, familial risk, PET avidity, prior cytology, significant growth, pregnancy, comorbidity and ability to follow up. The ACR itself provides FAQs and reporting resources because real cases require judgement.

A patient should follow the radiologist and treating clinician’s recommendation rather than choosing between FNA and follow-up from this calculator. If a report recommends urgent review, do not delay because a self-entered field produces a lower category.

Follow-up is longitudinal

When follow-up is recommended, comparison should use the same nodule and record dimensions, imaging characteristics and date. Growth is assessed by defined dimensional criteria, not by rounding one maximum diameter. A different operator or plane can produce small measurement differences.

Keep reports and images accessible to the care team. Missing prior imaging can lead to unnecessary uncertainty. The calculator does not schedule intervals or count years of stability; use the formal recommendation on the report and current clinical plan.

Communication and anxiety

Thyroid nodules are common, and many are benign. A point score can still cause anxiety when read without context. Ask the clinician to explain the feature, category, absolute concern, options and timing. Write questions before the visit rather than repeatedly changing dropdowns.

Seek prompt medical assessment for a new neck mass, rapid growth, breathing or swallowing difficulty, persistent voice change or concerning lymph nodes. Emergency symptoms require urgent care. Online arithmetic must never replace examination, diagnostic ultrasound or a needed biopsy.

Use the original ultrasound report

Transcribe descriptors only from a report prepared by a qualified imaging professional and keep the nodule size and date with the score. Do not infer composition, echogenicity, shape, margins or echogenic foci from a phone photograph. If the report wording does not map clearly to the categories, ask the radiologist or treating clinician rather than guessing points.