Dual-energy CT iodine quantification for characterizing focal thyroid lesions.

Background To determine the usefulness of dual-energy CT (DECT) iodine quantification to classify the focal thyroid lesions. Methods We retrospectively enrolled a total of 76 cytopathologically confirmed focal thyroid lesions (mean size: 1.9 cm). After drawing a region of interest on the DECT-derived iodine maps, the obtained iodine concentration values of thyroid nodules (IC_N) and normalized IC_N were compared between 3 groups: papillary thyroid carcinoma (PTC), benign nodule, and cyst. Results From all lesions, 46, 17, and 13 were assigned to the PTC, benign nodule, and cyst groups. IC_N was the highest in the benign nodule, lower in the PTC, and the lowest in the cyst (median [interquartile range]: 4.3 [3.13-5.48], 3.15 [2.29-4.01], 0.60 [0.33-0.88], all P < .001). Similarly, the normalized IC_N values were all statistically different from each other (P < .05).The multi-class area under the curves using the optimal cutoff values were 0.931 for IC_N and 0.918, 0.920 for normalized IC, respectively. Conclusion DECT iodine quantification could be helpful to classify the focal thyroid lesions.