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Abstract Summary and conclusion Thyroid nodules are very common in adults, found in 4–8% by palpation, in 10–41% by ultrasonography (US), and in 50% by pathologic examination at autopsy most nodules are benign, with less than 5% of them being malignant. Solitary thyroid nodule is defined as discrete mass, greater than or equal to 1 cm in diameter which occur in up to 4% of the population and are most often found in patients 30 to 50 years of age Surgery and radioiodine therapy have been the mainstay of therapy in the compressive thyroid nodules, but surgical complications have been reported in around 7–10% of cases as well as repeat surgery in the central or lateral compartments of the neck may be difficult because previous neck dissection may be associated with high rates of morbidity. The non-invasive and percutaneous methods like Ethanol ablation and Radiofrequency ablation are good alternatives to benign solid thyroid nodules, especially in patients refusing surgery and those with cosmetic problems. EA is effective in treatment of benign cystic thyroid nodules, but is less effective when used to treat benign solid thyroid nodules. 91 –Preprocedural US examination should be performed to evaluate thyroid nodules and to plan EA ablation: Size Volume calculated by the following equation: V = πabc / 6, where V is volume, a the largest diameter and b and c the other two per pendicular diameters. characteristics of the nodules Composition Vascularity Presence of abnormal lymph nodes in the neck Relationship between the target nodule and critical neck structures Three-method approach used in EA: Transisthmic approach(the best to use in EA), lateral approach and Cranio-caudal (longitudinal) approach. Trans-isthmic approach is the best approach for EA technique that allows clear continuous ultrasound monitoring of the relations of the nodule, the needle and expected location of the recurrent laryngeal nerve, thus minimizing the risks of chemical injury to that nerve or the esophagus The data regarding use of EA in solid nodules is variable and depends on the nodule size, volume of ethanol instilled, and nodule toxicity. Recently published study, however, demonstrated a success rate of 60% in solid nodule 92 US findings of successful ablation: Loss of intranodular vascular signal in Doppler US examination. Decreased nodule volume. Decreased echogenicity of the ablated nodule. Changes in size, echogenicity, and intranodular vascularity of the nodule should be evaluated on follow-up US examinations. Volume reduction (VR) is calculated using the following equation: -VR(%)= {initial volume (ml)- final volume (ml} x100 / initial volume Conclusion: • For cystic thyroid nodules EA is superior to RF ablation with respect to the mean number of treatment sessions required (1.2 vs. 1.7) and cost. Therefore, EA may be an appropriate first-line treatment for cystic thyroid nodules. • For predominantly cystic thyroid nodules (90% > cystic portion >50%) RF ablation can be used for initial treatment of thyroid nodules with >20% solid Component. • For predominantly solid thyroid nodules (solid portion >50%), EA is much less effective than is RF ablation. Although additional application of EA to predominantly solid nodules may achieve efficacies similar to those obtainable with RF ablation. |