Clinical Application of Iodine-Enhanced Image of Dual-source Computed Tomography in Distinguishing Benign and Malignant Thyroid Nodules

Objective To investigate the clinical application of iodine-enhanced image of dual-source computed tomography(DSCT) in distinguishing the benign and malignant thyroid nodules. Methods We calculated CT attenuation value and Iodine concentration of the thyroid nodules and adjacent normal thyroid tissues in 36 patients with total 47 thyroid nodules. And we utilized the receiver operating characteristic(ROC) curves by SPSS software to select the critical value of the optimum sensitivity and specificity, and compared its consistency with the diagnosis result of traditional morphology. Results The CT attenuation value and iodine concentration range of malignant nodules were 22.9-52.1 HUaverage (30.2±0.5)HUand -3.2-1.0 mg/ml(median -1.5 mg/ml), which was lower than those of benign nodules30.2-55.1 HU average (39.4± 0.7) HU and -0.5-1.8 mg/ml(median 0.9 mg/ml) (t=6.213, Z=-4.650, P=0.001, 0.000); The CT attenuation value and iodine concentration range of adjacent normal thyroid tissues of malignant nodules were 47.4~85.6 HUaverage (66.8±1.3)HU and 1.1-3.2mg/mlaverage(1.8±0.1)mg/ml, with no significant difference with those of benign nodules56.8-85.7 HU average (68.4±1.8)HU and 1.2-3.0 mg/ml average (1.7±0.1)mg/ ml), (t=3.753, 0.932, P=0.225, 0.112). There was correlation between the CT attenuation value and iodine concentration range of each group(r=0.755, 0.678, 0.813, 0.774, P=0.000). When the critical value was 0.15 mg/ml, the sensitivity was 81.50% and the specificity was 80.00%, which were in high consistency with traditional morphological diagnosis result (Kappa=0.742). Conclusion Iodine-enhanced images of DSCT with dual energy scan could measure the Iodine concentration of the thyroid nodules and adjacent normal thyroid tissues.The iodine concentration range of malignant nodules is lower than those of benign nodules. And it may be an implemental tool for the differential diagnosis of benign and malignant thyroid nodules.