ACR TI-RADS

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. Defined the five-category points system, the TR1–TR5 levels, and the size thresholds for FNA and ultrasound follow-up by TR level used here.

Tessler FN, Middleton WD, Grant EG. Thyroid Imaging Reporting and Data System (TI-RADS): A User’s Guide. Practical application of the chart, including its footnotes: a spongiform nodule scores 0 with no points added for other features, "anechoic" applies only to cystic or almost completely cystic nodules, and so no correctly scored nodule totals exactly 1 point. TI-RADS does not apply to a nodule already selected for FNA on other grounds (e.g. a growing nodule, suspicious lymph nodes, or a patient with a relevant history) — those still warrant sampling regardless of the TR level or size. Size is the largest diameter on ultrasound. TR1 and TR2 nodules are not recommended for FNA at any size.