Objective: Nodular disease of the thyroid is a common endocrinologic disorder. Five to fifteen percentage of all thyroid nodules are thought to be malignant. Current diagnostic modality of choice for characterization of thyroid nodules is fine needle aspiration biopsy (FNAB). We aimed to this study was to evaluate the color Doppler ultrasonography (CDUS) findings of patients with thyroid nodules and also to detect the role of CDUS differantiation between malignant and benign thyroid nodules.

Material and Method: One hundred and twenty nine nodules were included this study. These nodules were divided into benign and malignant nodules, according to their histopathologic and cytologic results. Localization of nodules, size and internal structure were investigated. CDUS were used to evaluate the type of vascularization, Peak systolic Velocity, peak diastolic velocity, systole/diastole (S/D) ratio, pulsatility index (PI), resistive index (RI), acceleration index (AI) and acceleration time (AT) of the nodules.

Results: Vascularization type were statistically significant different between benign and malignant nodules. There were also statistically significant differences between benign and malignant nodules at the S/D ratio, PI, RI, AI.

Conclusion: We think using together with US and RDUS may be contribution for the diagnosis and differentiating between nodules of benign and malign. It also prevented unnecessary FNAB.