Residual vital ratio: predicting regrowth after radiofrequency ablation for benign thyroid nodules
Lin Yan, Yukun Luo, Fang Xie, Mingbo Zhang, Jing Xiao
Abstract
PURPOSE: To determine a novel quantitative index, residual vital ratio(RVR) by contrast-enhanced ultrasound(CEUS) with conventional Ultrasound(US), to early predict nodule regrowth after radiofrequency ablation (RFA)for benign thyroid nodules. METHODS: This retrospective study evaluated 186 patients with 206 benign thyroid nodules underwent RFA. Patients were followed at 1, 3, 6, 12 months and every 12 months thereafter by conventional US, CEUS and clinical evaluation. RVR was defined as the initial ratio of residual vital volume to the total volume calculated by CEUS and conventional US at the first follow-up period after RFA. The relationship between RVR and regrowth was investigated. RESULTS: < .001) with the optimal cutoff value of 44.5% (sensitivity 80.8%, specificity 74.7%). CONCLUSION: RVR was not only an independent factor but also an early quantitative predictor for regrowth. If RVR was larger than 44.5%, the nodule tended to regrowth in the follow-up.