Fig. 3. Representative images.

(Good response) 46-year-old female Graves' disease patient showed mildly increased %uptake (2.6%). Notably, euthyroid patients had mean %uptake of 0.8 ± 0.5% as determined via same SPECT/CT protocol (11). Patient's initial MMI dose was 30 mg per day, and she achieved euthyroidism 130 days after initial MMI administration. Values of other variables investigated were SUVmax (98.48), SUVmean (30.03), functional thyroid mass (2330 g), T3 (400 ng/dL), free T4 (5.54 ng/dL), TSH (0.01 µIU/mL), TSHR-Ab (2.13 IU/L), and thyroid volume (77.6 mL). (Poor response) this 38-year-old female Graves' disease patient showed markedly increased %uptake of 12.66%. Initial MMI dose was 30 mg per day, but she had not achieved euthyroidism by last follow-up time-point of 167 days post-MMI administration. Values of other variables investigated were SUVmax (362.43), SUVmean (149.06), functional thyroid mass (6827 g), T3 (461 ng/dL), free T4 (17.74 ng/dL), TSH (0.05 µIU/mL), TSHR-Ab (33.14 IU/L), and thyroid volume (45.8 mL). Upper row: planar scintigraphy, middle row: SPECT (coronal and transaxial images), bottom row: SPECT/CT (coronal and transaxial images). MMI = methimazole, SPECT/CT = single-photon emission computed tomography/computed tomography, SUV = standardized uptake value, TSH = thyroid-stimulating hormone, TSHR-Ab = thyroid-stimulating hormone receptor antibody