Radiofrequency ablation of benign thyroid nodules: evaluation of the treatment efficacy using ultrasonography.
OBJECTIVE
The aim of this study was to evaluate the efficacy of radiofrequency (RF) ablation for benign thyroid nodules and assess the usefulness of internal factors (ultrasonographic findings) and external factors (treatment-related findings) in prediction of treatment efficacy.


METHODS
We evaluated 22 benign thyroid nodules from 19 patients treated with RF ablation between March 2010 and January 2013. The internal and external factors of these nodules were retrospectively reviewed and correlated with the therapeutic success and the volume reduction ratio (VRR). The volume and size of the nodules were determined before treatment, and the VRR was calculated at 6-month and 1-year follow-up examinations after RF ablation. Therapeutic success was defined as a >50% volume reduction.


RESULTS
The mean VRRs were 66.1±18.7% at 6 months and 74.3±16.7% at 1 year. The therapeutic success rate after 6 months and 1 year was 81.8% and 90.9%, respectively. At the 1-year follow-up, the margin of the nodule correlated with therapeutic success. Most of the successfully ablated nodules showed well-defined margins on initial ultrasonography (18/20, 90%) (P=0.026). In addition, nodules with ill-defined margins showed a tendency toward having a low VRR at the 6-month and 1-year follow-up examinations.


CONCLUSIONS
RF ablation was effective in decreasing the volume of benign thyroid nodules. Thyroid nodules with well-defined margins tended to show successful outcomes at the 1-year follow-up examination after RF ablation.
Department of Radiology, Chung-Ang University Hospital, Seoul, Korea.
Hye Shin
0000-0001-7260-7467
HS
Ahn
Department of Radiology, New Korea Hospital/Human Medical Imaging and Intervention Center, Gimpo, Korea.
Soo Jin
0000-0001-8233-1388
SJ
Kim
Department of Radiology, Chung-Ang University Hospital, Seoul, Korea.
Sung Hee
0000-0003-1244-703X
SH
Park
Department of Radiology, Chung-Ang University Hospital, Seoul, Korea.
Mirinae
0000-0002-8989-9504
M
Seo
Ablation techniques; Thyroid nodule; Ultrasonography