High risk history is not defined by the SRU. ATA definition is of thyroid cancer in one or more first degree relatives, history of external beam radiation as a child, exposure to ionizing radiation in childhood or adolescence, prior hemithyroidectomy with discovery of thyroid cancer, FDG avidity on prior PET, MEN2/FMTC-associated protooncogene mutation, or calcitonin > 100 pg/mL.
Abnormal lymph nodes: Short axis < 10 mm in zone 2 is defined as normal at our institution. SRU definition is of > 7 mm short axis, heterogeneous echotexture or cystic areas, calcifications, rounded morphology, and causing mass effect. ATA definition is of > 5 mm short axis, cystic areas, calcifications, peripheral vascularity, rounded morphology, absent fatty hilus, and hypoechogenicity.