What Does Thyroid Nodule TI-RADS Mean?

Thyroid nodules are extremely common. StatPearls reports that up to 60% of adults have at least one, and that only about 5% prove to be cancer. A doctor's hands find nodules in 5% to 7% of adults. Ultrasound finds them in 20% to 76%.

That gap is the whole problem. Ultrasound finds far more nodules than are worth biopsying. TI-RADS exists to sort them.

TI-RADS stands for Thyroid Imaging Reporting and Data System. The American College of Radiology built it to do three things: guide what to do with nodules found by accident, create shared wording for describing them, and set up a standard risk score.

StatPearls notes that thyroid-stimulating hormone, or TSH, is checked early. A low TSH usually points toward a benign nodule. A normal or high TSH is more concerning, because cancer risk rises along with the TSH level.

TSH is not part of the TI-RADS score. It is a separate thread in the same decision.

ACR states that each nodule is assessed on composition, echogenicity, shape, margin, and echogenic foci. Each feature earns points. The points add up.

Composition is what the nodule is made of. Cystic, meaning fluid-filled, and spongiform score 0. A mix of solid and fluid scores 1. Fully solid scores 2.

Echogenicity is how bright the nodule looks compared with normal thyroid tissue. Hyperechoic, meaning brighter, scores 1. Isoechoic, meaning the same brightness, scores 1. Hypoechoic, meaning darker, scores 2. Markedly hypoechoic scores 3.

Shape has one question. Wider-than-tall scores 0. Taller-than-wide scores 3. A nodule growing across normal tissue planes is the concern.

Margin is the edge. Smooth scores 0. Ill-defined also scores 0. Lobulated or irregular scores 2. Extrathyroidal extension, meaning the nodule pushes beyond the gland, scores 3.

Echogenic foci are bright specks inside the nodule. None scores 0. Macrocalcifications, which are large and coarse, score 1. Peripheral or rim calcifications score 2. Punctate echogenic foci, which are tiny bright dots, score 3.

The totals map to five levels.

• TR1: 0 points. Benign.
• TR2: 2 points. Not suspicious.
• TR3: 3 points. Mildly suspicious.
• TR4: 4 to 6 points. Moderately suspicious.
• TR5: 7 or more points. Highly suspicious.

Here is the part patients rarely hear. The TR level alone does not trigger a biopsy. The level is paired with the nodule's largest measurement.

• TR1 and TR2: no fine needle aspiration, regardless of size.
• TR3: aspirate at 2.5 cm or larger. Follow with repeat ultrasound at 1.5 cm or larger.
• TR4: aspirate at 1.5 cm or larger. Follow at 1.0 cm or larger.
• TR5: aspirate at 1.0 cm or larger. Follow at 0.5 cm or larger.

So a TR5 nodule measuring 0.8 cm is watched, not biopsied. That feels wrong to many people. The reasoning is that very small thyroid cancers are common, slow, and often never cause harm, while biopsying every one of them creates far more anxiety and surgery than benefit.

A solid nodule, darker than the surrounding gland, wider than tall, with smooth edges and tiny bright dots inside. Points: solid 2, hypoechoic 2, wider-than-tall 0, smooth 0, punctate foci 3. Total 7. That is TR5. Measured at 1.2 cm, biopsy is recommended. The same nodule at 0.7 cm would be followed instead.

A part-solid, part-fluid nodule, the same brightness as the gland, wider than tall, smooth-edged, with a coarse calcification. Points: mixed 1, isoechoic 1, wider-than-tall 0, smooth 0, macrocalcification 1. Total 3. That is TR3. At 2.0 cm it is followed. At 2.6 cm it is aspirated.

RadiologyInfo describes ultrasound-guided fine needle aspiration in concrete terms. The needle is usually 25 or 27 gauge and 1.5 inches long, thinner than the needle used for most blood draws. The radiologist watches the needle on ultrasound as it enters the nodule. Cells are spread on slides for a pathologist. The whole visit is usually under 30 minutes.

StatPearls describes complications as rare. A neck hematoma, meaning a collection of blood, is the one that gets attention, but it is uncommon. Pain, brief swelling, infection, and a fainting reaction are also listed as rare. Blood thinners usually do not have to be stopped for the procedure.

The biopsy result comes back in its own system, called Bethesda. StatPearls lists the six categories. The NIH Endotext review sets out the cancer risk attached to each one, for the version that does not count NIFTP as cancer:

• Nondiagnostic: 5% to 10%
• Benign: 0% to 3%
• Atypia of undetermined significance: 10% to 30%
• Follicular neoplasm: 25% to 40%
• Suspicious for malignancy: 50% to 75%
• Malignant: 97% to 99%

A nondiagnostic result is not a benign result. It means the sample did not contain enough usable cells, and the usual answer is to repeat it.

It does not diagnose cancer. It is a picture score built from what sound waves show, nothing more.

It also says nothing about thyroid function. A nodule can be TR2 and still be making too much hormone, or TR5 in a gland that works perfectly.

Questions worth asking about your own report:

• What was the total point score, and which features earned points?
• What is the largest dimension, in centimeters?
• Given that level and that size, is biopsy or follow-up the recommendation?
• If follow-up, at what interval, and for how long?
• Are there several nodules, and was each one scored separately?

• https://www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/Reporting-and-Data-Systems/TI-RADS
• https://pmc.ncbi.nlm.nih.gov/articles/PMC8864691
• https://pmc.ncbi.nlm.nih.gov/articles/PMC9009349/
• https://www.ncbi.nlm.nih.gov/books/NBK535422/
• https://www.ncbi.nlm.nih.gov/books/NBK557883/
• https://www.radiologyinfo.org/en/info/thyroidbiopsy
• https://www.ncbi.nlm.nih.gov/books/NBK278969/table/thyroid-nod-canc-eld.T.bethesda_system_f/