ACR TI-RADS (Thyroid Nodule Risk Stratification)

ACR TI-RADS assigns points for composition, echogenicity, shape, and margin (single most suspicious choice per category), plus echogenic foci, for which multiple findings may be summed. The total determines the TR level: 0 points TR1 (benign), up to 2 points TR2 (not suspicious), 3 points TR3 (mildly suspicious), 4-6 points TR4 (moderately suspicious), and 7 or more points TR5 (highly suspicious). Purely cystic and spongiform nodules are benign by definition and are assigned TR1 without further scoring. Biopsy and surveillance are size dependent: FNA is suggested for TR3 nodules at 2.5 cm or larger, TR4 at 1.5 cm or larger, and TR5 at 1.0 cm or larger, with ultrasound follow-up at lower thresholds (TR3 >= 1.5 cm; TR4 >= 1.0 cm; TR5 >= 0.5 cm).