Qualitative and quantitative evaluation of solitary thyroid nodules with contrast-enhanced ultrasound: initial results

To assess the feasibility of contrast-enhanced ultrasound (CEUS) of the thyroid gland and to evaluate the potential of this method for characterising solitary thyroid nodules.18 patients affected by solitary thyroid nodules (size range: 0.6 to 3.6 cm; mean: 1.8 cm) confirmed by surgery (nine papillary carcinomas, four follicular carcinomas, three hyperplasias, one follicular adenoma and one Plummer's adenoma) underwent pulse inversion US at low M.I. (0.06 to 0.08) after i.v. injection of a 2.4-mL bolus of SonoVue. Baseline echogenicity and the dynamic enhancement pattern of each nodule, in comparison with adjacent thyroid parenchyma, were assessed. Signal intensity values on grey-scale images were also calculated at baseline, 30 s, 60 s and 120 s after SonoVue administration. Following administration of SonoVue, malignant nodules showed absent (4 out of 13), faint dotted (4 out of 13) and diffuse (5 out of 13) contrast enhancement, in this last case inhomogeneous (4 out of 5 cases) or homogeneous (1 out of 5). Benign nodules showed diffuse contrast enhancement, both homogeneous (3 out of 5) and heterogeneous (2 out of 5). Quantitative data have confirmed subjective findings, but CEUS never modified precontrast analysis. CEUS of thyroid gland is a feasible technique, but overlapping findings seem to limit the potential of this technique in the characterization of thyroid nodules.