Iodine Concentration on Dual-energy Contrast Enhanced CT in Differential Diagnosis of Thyroid Nodules / 中国医学影像学杂志

ABSTRACT

Purpose To investigate the clinical application of iodine concentration using dual-energy contrast enhanced CT in distinguishing malignant from benign thyroid nodules. Materials and Methods Patients with a total of 90 pathology proven thyroid nodules (60 malignant, 30 benign) underwent dual-energy contrast enhanced CT scanning. The iodine concentration and CT value were measured in arterial phase and venous phase, then the normalized iodine concentration (NICnod) and the normalized CT value were calculated. All results were compared in each groups, while morphology and capsule of these nodules on iodine image were analyzed. Results The morphology and capsule of nodules on iodine image were significantly different between benign and malignant nodules (Z=- 4.55, P<0.05). On iodine image, the sensitivity of partial capsule diagnosing malignant nodules was 78.33% with specificity of 66.67%. The NICnod and normalized CT value for normal group, benign group and malignant group showed significant differences in arterial phase and venous phase (F=36.87-69.89, P<0.05); the NICnod and normalized CT value between benign group and malignant group showed statistic difference in arterial phase (Z=- 3.48- -2.33, P<0.05), and those among normal group, benign group and malignant group also showed statistic differences (Z= -7.01- - 4.87, P<0.05). NICnod had significant correlation with normalized CT value in each phases (r=0.89, 0.74 and 0.75, P<0.05). When using NICnod and normalized CT value of 0.76 and 0.79 to differentiate malignant thyroid nodules, the area under ROC curve values were 0.91 and 0.92. NIC and normalized CT value showed a good consistency with iodine map in venous phase (Kappa=0.762 and 0.768), Combining morphology and capsule of nodules on iodine image, the sensitivity was 90.01% and the specificity was 93.60%. Conclusion Iodine concentration with dual-energy contrast enhanced CT scanning can differentiate malignant from benign thyroid nodules; combining morphology and capsule of nodules improves the accuracy of diagnosis.