1.Success rate of PEI were assessed according to nodule vascularity, nodule size, ratio of cystic component, amount of injected ethanol, degree of intranodular echo-staining just after ethanol injection and the number of PEI sessions.
2. 30 solid nodules were treated by PEI.
3.16/30 had 90% decrease volume.
4. 2/30 nodules showed a good response (50–90% decrease in volume.
5.5/30 nodules showed an incomplete response (10–50% decrease in volume.
6. 7/30 nodules showed a poor response (10% or less decrease in volume).
7. Failure of PEI ablation an association of nodule vascularity (p = 0.002).
8.Good outcomes occurred with the degree of intranodular echo-staining just after ethanol injection (p = 0.003).
9. No such association was observed with regard to nodule size, ratio of cystic component, amount of infused ethanol and the number of PEI sessions.
10. No serious complications were observed during or after PEI.
11. The success rate of PEI was 60%, and nodule vascularity and intranodular echo-staining on colour Doppler ultrasonography were useful in predicting the success rate of EA for benign, predominantly solid thyroid nodules.
12. Advantages of PEI include low risk, low cost, practicability in the outpatient clinic and ease of performance.
13.PEI is rarely selected for the treatment of a solid thyroid nodule compared with the options of clinical follow-up, Thyroid RFA, radioiodine therapy or surgery.
14. Identification of factors that might aid in the accurate prediction of the success of PEI in the treatment of solid thyroid nodules could result in more frequent clinical use of PEI.
15.Adequate coverage of the target nodule, as indicated by its echogenicity (called intranodular echo-staining), was achieved by adjusting the injection of ethanol under ultrasonography guidance.
16.Successful treatment was achieved in 18 nodules (60%). Of these, one showed scanty vascularity, eight showed low vascularity, seven showed iso-vascularity and two showed mildly increased vascularity, as determined by colour Doppler.
17. Thyroid radiofrequency ablation (RFA) was performed for two nodules showing an incomplete response.
18. Seven nodules, which included four with mildly increased vascularity and three with markedly increased vascularity, were regarded as having a poor response (≤10% decrease in volume).
19. For all nodules showing a poor response, RFA was performed without long-term ultrasonography follow-up.
20. Owing to its ease of use, safety, low cost and effectiveness, PEI is the first-choice tool for use in the treatment of benign cystic thyroid nodules.
21. RFA has proven to be a feasible and effective tool for treatment of solid nodules; however, its disadvantage lies in the high cost when compared with PEI.
22. In the present study, the mean success rate (60%) and volume reduction rate (64.3%) were lower than those reported by Baek.
23. Poor venous washout of injected ethanol during PEI was closely related to good intranodular echo-staining and good results, whereas moderate venous washout was closely related to poor intranodular echo-staining and poor results.
24. Effective ethanol ablation is possible only when the ethanol stays within the thyroid nodule and there is no venous washout of the injected ethanol.
25. A long stay of ethanol with little washout can have an effect on sclerotic mechanisms of ethanol, which include coagulative necrosis, small-vessel thrombosis and haemorrhagic infarction.
26. PEI may become the first-line treatment when a symptomatic solid thyroid nodule shows low- or isovascularity in colour Doppler ultrasonography.
27.The fact that PEI of large solid thyroid nodules is less successful than PEI of small ones is generally accepted.
28.However, intranodular echo-staining of the injected ethanol with no washout is more important than nodule size or the amount of ethanol injected per session.
29.If PEI was applied to predominantly solid thyroid nodules with low vascularity and high echo-staining without venous washout, we could expect a higher success rate before and during PEI.
30. Using this guideline for the selection of thyroid nodules, we could improve the therapeutic results of benign predominant thyroid nodules by choosing the most efficient therapeutic modality.
31.In summary, the success rate of PEI was 60%, and PEI of predominantly solid nodules was more effective in less vascular and more echo-staining thyroid nodules than in more vascular and less echo-staining ones.
32.Therefore, colour Doppler ultrasonography may be a useful tool for the prediction of treatment outcomes for PEI of benign, predominantly solid thyroid nodules.