Role of color Doppler ultrasonography in the preoperative management of cold thyroid nodules.

OBJECTIVE To evaluate the application of color flow Doppler (CFD) sonography in the preoperative management of benign and malignant cold thyroid nodules. DESIGN Eighty-five patients with a cold thyroid nodule larger than 1cm were examined with CFD sonography prior to thyroidectomy. The histological examination revealed that 18 (21%) patients had malignant nodules and 67 (79%) had benign ones. The sonographic characteristics of the nodules used for evaluation were: a) absence of vascularization, b) presence of peripheral vascularization, c) presence of central vascularization and d) size of the nodule. The correlations between the pre-operative sonographic characteristics, as defined above, and the histological findings of the nodules were determined. results: The results showed that the vascular signals were absent in 4/18 (22%) of malignant nodules and 16/67 (23%) of benign ones. The smaller nodules (<2.5 cm.) were more frequently avascular (15/37=40%) compared to the larger ones (5/48=10%) (p<0.05). Moreover, for the nodules with vascularization, the peripheral distribution of vascularization was more frequently encountered in benign nodules (p<0.01 specificity=0.77, sensitivity=0.46), while central vascularization was more frequent in malignant ones (p<0.01, specificity=0.70, sensitivity=0.66). Thus, absence of vascularization in a nodule does not exclude the probability of malignancy, since vascularization depends on the size rather than the histological features of the nodule. Furthermore, for the vascularized nodules, peripheral distribution of vascularization is a characteristic of benignancy with high specificity, while central distribution is a characteristic of malignancy with medium specificity. CONCLUSIONS CFD sonography contributes to the differential diagnosis of the large vascularized nodules, but it is less helpful in the smaller non-vascularized ones.