Application of contrast-enhanced ultrasound in minimally invasive ablation of benign thyroid nodules

OBJECTIVE: This study aimed to investigate the application value of contrast-enhanced ultrasound (CEUS) before and after minimally invasive ablation procedures for benign thyroid nodule(s) (BTN). METHODS: This prospective study included patients with BTNs scheduled to undergo ultrasound-guided minimally invasive ablation treatment. CEUS was performed before and after ablation (at 1 day, and 1, 6, and 12 months after ablation). Changes in microvascular perfusion and the volume of BTNs were noted and assessed. RESULTS: Sixty-two patients (62 BTNs), who underwent ablation procedures between June 2016 and August 2020, were included. All lesions were confirmed by biopsy, and histopathological results were obtained before ablation treatment. On preoperative CEUS, the lesions exhibited hyperenhancement (53.23%) or iso-enhancement (46.77%) during the arterial phase, and all lesions exhibited iso-enhancement in the venous and late phases. One day after ablation, none of the BTNs exhibited obvious enhancement on CEUS. One (1.61%) lesion was re-treated due to a nodule-like enhancement area detected by CEUS at the 6-month follow-up. The mean nodular volume reduction rate (VRR) at 1, 6, and 12 months follow-up demonstrated no significant difference between the two ablation groups (microwave ablation versus radiofrequency ablation). Twelve months after ablation, the mean (±SD) VRR of all BTNs was 60.3 ​± ​10.3%. CONCLUSION: CEUS helped guide treatment decisions for BTNs before ablation treatment. Moreover, it could also be used to accurately and noninvasively evaluate treatment efficacy.