Clinical value of contrast-enhanced ultrasonography in focal hypoechogenic lesions of thyroid

Objective The objectives of this study were to analyze the accuracy of contrast-enhanced ultrasonography (CE-US) in diagnosing focal hypoechogenic lesions of the thyroid (FHLT), and to explore the clinical value of CE-US in the diagnosis of FHLT. Methods Patients undergoing CE-US and ultrasound-guided fine needle aspiration (US-FNA) of FHLT at First Hospital of China Medical University between January 2017 and December 2018 were selected for the study; this included patients with papillary thyroid carcinoma (PTC), subacute thyroiditis (SAT) and focal Hashimoto thyroiditis (FHT). All patients underwent color Doppler ultrasonography (CD-US) after which thyroid image reporting and data system (TI-RADS) grading were done. Then, each patient underwent CE-US and US-FNA. The results of the CE-US were analyzed using descriptive statistics. The cytopathological results from the US-FNAs were the gold standard used to confirm the diagnoses. Results A total of 56 patients were selected for the study. In the PTC group (n = 16), grading was as follows: TI-RADS4a, n = 3; TI-RADS4b, n = 12; and TI-RADS4c, n = 1. More patients with PTC showed heterogeneous hypoenhancement (n = 15) than heterogeneous isoenhancement (n = 1) on CE-US. In the SAT group (n = 24), grading was as follows: TI-RADS3, n = 1; TI-RADS4a, n = 18; TI-RADS4b, n = 5. Fewer patients with SAT showed heterogeneous hypoenhancement (n = 2) than heterogeneous isoenhancement (n = 22) on CE-US. In the FHT group (n = 16), grading was as follows: TI-RADS3, n = 1; TI-RADS4a, n = 11; TI-RADS4b, n = 4. Of those in the FHT group, one patient showed heterogeneous isoenhancement, one patient showed heterogeneous hypoenhancement, and 14 showed uniform isoenhancement on CE-US. The diagnostic accuracy of CD-US alone differed significantly from that of CD-US + CE-US (p < 0.05). Conclusion CE-US has a high diagnostic accuracy for FHLT and can be used to identify PTC, SAT, and FHT.