OBJECTIVE: To investigate the impact of contrast-enhanced ultrasound on the efficacy of microwave ablation in the treatment of benign thyroid tumors, as well as its effect on thyroid function, to assess its application value. METHODS: We retrospectively analyzed data from 60 patients with benign thyroid nodules treated at Sichuan Provincial People's Hospital from January 2021 to December 2021. All patients underwent microwave ablation. Based on the intraoperative assessment of the ablation effect, they were divided into a contrast-enhanced ultrasound group (n=34) and a conventional ultrasound group (n=26). Postoperatively, the treatment outcomes were classified into complete ablation or the presence of residual nodules. We also assessed the recurrence rate one year after treatment, along with inflammatory factors, stress response indicators, and effects on thyroid function. RESULTS: The complete ablation rate for thyroid nodules in the contrast-enhanced ultrasound group was significantly higher than that in the conventional ultrasound group (P<
0.05). Intraoperative measurements revealed lower ablated nodule volumes, bleeding volumes, and in situ replacement rates in the contrast-enhanced ultrasound group, with statistically significant differences (P<
0.05). Preoperative thyroid function hormone indicators, inflammatory factors and stress response indicators did not significantly differ between the two groups. Postoperatively, both groups had lower levels of free triiodothyronine (FT3) and free thyroxine (FT4), along with higher levels of thyroid-stimulating hormone (TSH), white blood cells (WBC), serum C-reactive protein (CRP), interleukin-6 (IL-6), norepinephrine (NE), epinephrine (E), and cortisol (Cor) compared to preoperative levels. However, the contrast-enhanced ultrasound group demonstrated higher FT3 and FT4 levels and lower WBC, serum CRP, IL-6, NE, E, Cor and TSH levels than the conventional ultrasound group, with statistically significant differences (all P<
0.05). No statistically significant differences in complication rates were observed between the two groups. CONCLUSION: Contrast-enhanced ultrasound in microwave ablation for benign thyroid nodules can improve the complete ablation rate, reduce recurrence, and have a minimal impact on thyroid function, without increasing complication rates. It is recommended for clinical use.