American College of Radiology TI-RADS Reporting System
Reportability/Date of diagnosis--Thyroid: Is category Thyroid imaging reporting and data system (TI-RADS) 4 (4a/4b) or TI-RADS 5 on imaging diagnostic of thyroid cancer, and if so, can we use the date of the impression on the scan that states either of these categories as the diagnosis date?
TI-RADS 5 is reportable for thyroid cancer unless disproven by other documentation and the date of the TI-RADS 5 scan may be used as the date of diagnosis if this is the earliest mention of the malignancy. TI-RADS 5 is "probably malignant nodules (>80% malignancy)."
TI-RADS 4 (including 4a and 4b) is not reportable for thyroid cancer. TI-RADS 4 is "suspicious nodules (5-80% malignancy)." TI-RADS 4b is "suspicious (10-80% malignancy)."