[Qualitative evaluation of thyroid nodules with gray-scale contrast-enhanced ultrasound]

To assess the feasibility of gray-scale contrast-enhanced ultrasound for characterizing thyroid nodules.

Forty thyroid nodules from 35 patients were studied both by conventional techniques and gray-scale contrast-enhanced ultrasound. Of the nodules examined, 15 were benign and 25 malignant. The enhancement of echogenicity was evaluated. The diagnosis was confirmed by surgical biopsy and histopathological examination.

The study using gray-scale contrast-enhanced ultrasound showed absent contrast-enhancement in 9 of 25 malignant nodules and 1 of 11 benign solitary nodules; intense enhancement in 6 of 25 malignant nodules, with perfusion defect in the center; diffuse faint enhancement in 10 of 25 malignant nodules and 10 of 11 benign solitary nodules. Benign cystic nodules all showed absent enhancement in the cystic components and 2 of 4 intense enhancement in the solitary components.

Gray-scale contrast-enhanced ultrasonography imaging may be a useful tool for evaluating the perfusion of thyroid nodules. Solitary nodules showing absent enhancement or intense enhancement with absent enhancement in the nodular center may suggest malignant.