Fig. 2

Integrated discrimination improvement analysis of TSH alone as compared to ITA-PSV and TSH to predict increase in LT4 ≥ 50 μg. The predictability of an increase in LT4 ≥ 50 μg based on both ITA-PSV and TSH was significantly increased (27.9%, p = 0.009) as compared to TSH alone. Abbreviations: TSH, thyroid stimulating hormone; ITA-PSV, inferior thyroid artery peak systolic velocity; LT4, levothyroxine