Chong-Ke Zhao1,2,3, Hui-Xiong Xu1,2,3, Feng Lu1,2,3, Li-Ping Sun1,2,3, Ya-Ping He1,2,3, Le-Hang Guo1,2,3, Xiao-Long Li1,2,3, Xiao-Wan Bo1,2,3, Wen-Wen Yue1,2,3. 1. Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Ultrasound Research and Education Institute, Tongji University School of Medicine, Shanghai, China. 2. Thyroid Institute, Tongji University School of Medicine, Shanghai, China. 3. Shanghai Research Center for Thyroid Diseases, Shanghai, China.
Abstract
OBJECTIVE: To assess the factors associated with initial incomplete ablation (ICA) after radiofrequency ablation for benign thyroid nodules (BTNs). MATERIALS AND METHODS: 69 BTNs (mean volume 6.35±5.66 ml, range 1.00-25.04 ml) confirmed by fine-needle aspiration cytology (FNAC) in fifty-four patients were treated with ultrasound-guided percutaneous radiofrequency ablation (RFA) and the local treatment efficacy was immediately assessed by intra-procedural contrast-enhanced ultrasound (CEUS). The RFA was performed with a bipolar electrode (CelonProSurge 150-T20, output power: 20 W). CEUS was performed with a second generation contrast agent under low acoustic power (i.e. coded phase inversion, CPI). Characteristics of clinical factors, findings on conventional gray-scale ultrasound, color-Doppler ultrasound, and CEUS were evaluated preoperatively. Factors associated with initial ICA and initial ICA patterns on CEUS were assessed. Volume reduction ratios (VRRs) of ICA nodules were compared with those with complete ablation (CA). RESULTS: The RFA procedures were accomplished with a mean ablation time and mean total energy deposition of 11.13±3.39 min (range, 5.38-22.13 min) and 12612±4466 J (range, 6310-26130 J) respectively. CEUS detected initial ICA in 21 of 69 (30.8%) BTNs and 16 (76.2%) of the 21 BTNs with initial ICA achieved CA after additional RFA, leading to a final CA rate of 92.8% (64/69). The factors associated with initial ICA were predominantly solid nodule, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound (all P < 0.05). The mean VRRs of all BTNs were 23.4%, 54.4% and 81.9% at the 1-, 3- and 6-month follow-up, respectively. All BTNs achieved therapeutic success in this series in that all had VRRs of >50% at the 6-month follow-up, among which 7 nodules (10.1%) had VRRs of >90%. There were significant differences in VRRs between ICA nodules and CA nodules at the 3- and 6-month follow-up (all P < 0.05). CONCLUSION: The factors associated with initial ICA after RFA for BTNs were predominantly solid nodules, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound. CEUS assists quick treatment response evaluation and facilitates subsequent additional RFA and final CA of the nodules. Nodules with CA achieve a better outcome in terms of VRR in comparison with those with ICA.
OBJECTIVE: To assess the factors associated with initial incomplete ablation (ICA) after radiofrequency ablation for benign thyroid nodules (BTNs). MATERIALS AND METHODS: 69 BTNs (mean volume 6.35±5.66 ml, range 1.00-25.04 ml) confirmed by fine-needle aspiration cytology (FNAC) in fifty-four patients were treated with ultrasound-guided percutaneous radiofrequency ablation (RFA) and the local treatment efficacy was immediately assessed by intra-procedural contrast-enhanced ultrasound (CEUS). The RFA was performed with a bipolar electrode (CelonProSurge 150-T20, output power: 20 W). CEUS was performed with a second generation contrast agent under low acoustic power (i.e. coded phase inversion, CPI). Characteristics of clinical factors, findings on conventional gray-scale ultrasound, color-Doppler ultrasound, and CEUS were evaluated preoperatively. Factors associated with initial ICA and initial ICA patterns on CEUS were assessed. Volume reduction ratios (VRRs) of ICA nodules were compared with those with complete ablation (CA). RESULTS: The RFA procedures were accomplished with a mean ablation time and mean total energy deposition of 11.13±3.39 min (range, 5.38-22.13 min) and 12612±4466 J (range, 6310-26130 J) respectively. CEUS detected initial ICA in 21 of 69 (30.8%) BTNs and 16 (76.2%) of the 21 BTNs with initial ICA achieved CA after additional RFA, leading to a final CA rate of 92.8% (64/69). The factors associated with initial ICA were predominantly solid nodule, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound (all P < 0.05). The mean VRRs of all BTNs were 23.4%, 54.4% and 81.9% at the 1-, 3- and 6-month follow-up, respectively. All BTNs achieved therapeutic success in this series in that all had VRRs of >50% at the 6-month follow-up, among which 7 nodules (10.1%) had VRRs of >90%. There were significant differences in VRRs between ICA nodules and CA nodules at the 3- and 6-month follow-up (all P < 0.05). CONCLUSION: The factors associated with initial ICA after RFA for BTNs were predominantly solid nodules, nodule close to danger triangle area, nodule close to carotid artery, and peripheral blood flow on color-Doppler ultrasound. CEUS assists quick treatment response evaluation and facilitates subsequent additional RFA and final CA of the nodules. Nodules with CA achieve a better outcome in terms of VRR in comparison with those with ICA.
Authors: Hye Sun Park; Jung Hwan Baek; Auh Whan Park; Sae Rom Chung; Young Jun Choi; Jeong Hyun Lee Journal: Korean J Radiol Date: 2017-05-19 Impact factor: 3.500