Gray Scale and Colour Doppler Sonography in the Evaluation of Follicular Neoplasms of Thyroid

Abstract

Introduction: Follicular neoplasms of the thyroid gland include benign follicular adenoma and follicular carcinoma. Currently, a follicular carcinoma cannot be distinguished from a follicular adenoma based on cytologic, sonographic, or clinical features alone. Aim: To evaluate the gray scale and colour Doppler findings in differentiation of follicular carcinoma from follicular adenoma of thyroid. Materials and Methods: From January 2013 through December 2013, ultrasound images of 40 patients with histopathologically proven diagnosis of follicular carcinoma and follicular adenoma were studied retrospectively. The following characteristics of each nodule were evaluated: margins, internal contents, echo texture, halo, presence and pattern of calcification, pattern of vascularity, Resistive Index (RI) of intranodular/ perinodular vessels. The frequencies of the ultrasound features were compared by χ2 tests. The relative risk of malignancy was determined using logistic regression analysis. Results: Lobulated/poorly defined margins, predominantly solid composition, hypoechoic echotexture and thick incomplete or absent halo were associated with follicular carcinoma (p0.7 were more frequently observed in follicular carcinoma subgroup. Logistic regression analysis demonstrated that lobulated/poorly defined margins, predominantly solid contents, thick incomplete or absent halo, Central/ central > peripheral pattern of vascularity and Resistive Index (RI) of > 0.7 in intranodular/perinodular vessels were associated with significant increase in the relative risk of follicular carcinoma. Conclusion: Gray scale and colour Doppler sonographic characteristics provide useful information for differentiating follicular carcinoma from follicular adenoma of thyroid.

Keywords

• cytology
• follicular adenoma
• follicular carcinoma
• imaging features