Thyroid Tumor Ablation with Ethanol (PEI) 101: The Basics
The basic methods for doing PEI for benign thyroid cysts,mixed cyst/solid and solid nodules with references.
Comments by DR.G.
1.PEI Ethanol ablation uses a high concentration (95–99%) of ethanol.
2.The skin is punctured with various needles based on the thickness of the cyst fluid.
3.The nodule is approached through the thyroid isthmus to prevent ethanol leakage during the procedure.
4.The method of ethanol instillation depends on the solid component of the nodule.
5. A cystic or predominantly cystic nodule, the tip of the needle is inserted into the center of the cyst, as much fluid as possible is aspirated, and then ethanol is injected.
6.If the cyst contents are viscous, the fluid is aspirated using a large-bore needle, followed by irrigation with normal saline to remove internal debris and colloid material before ethanol instillation.
7. The volume of ethanol injected is usually 50% of the aspirated fluid volume.
8.After 2 minutes of ethanol retention with the needle in place, the injected ethanol is removed completely and the needle is withdrawn.
9.If a predominantly solid nodule contains a cystic component, the latter is punctured, almost completely aspirated, and an appropriate amount of ethanol is instilled.
10. The tip of the needle is subsequently inserted into the solid component of the target nodule, followed by infusion of an appropriate volume of ethanol.
11. That volume is based on nodule size and echogenicity of the solid portion.
12.In treating a purely solid nodule, ethanol is injected directly into the nodule.
13.Adequate coverage of the target nodule, as indicated by its echogenicity (called intranodular echo-staining), is achieved by adjusting the injection of ethanol under US guidance.
14.After injection, the needle is rapidly withdrawn.
Radiofrequency ablation is performed using a generator and internally cooled 7-cm electrodes with an 18-gauge active tip measuring 0.5, 0.7, or 1 cm (2,5,7). The RF power and the size of the active tip chosen depend on the size and internal characteristics of the targeted nodule. The initial RF power is usually 30–50 W with a 1-cm active tip, but may be 10 W with a 0.5-cm tip or 20 W with a 0.7-cm tip. If a transient hyperechoic zone does not appear at the tip of the electrode within 5–10 seconds, the RF power on a 1 cm tip is increased at 10 W increments to a maximum of 80 W (30 W with a 0.5 cm tip and 50 W with a 0.7 cm tip). Using a trans-isthmic approach, the electrode is inserted from the isthmus to the lateral aspect of a target nodule. The entire length of the electrode should be visualized to minimize possible complications. Benign thyroid nodules can be treated using the moving-shot technique (2,38,39). Given that most nodules are usually ellipsoid in shape, there is little margin between the nodule and the normal thyroid parenchyma. Therefore, a fixed electrode technique, which creates a round ablation zone, is considered unsuitable. For this procedure, the target nodule is divided into multiple small conceptual ablation units and RFA is performed unit-by-unit by moving the electrode. The electrode tip is initially positioned in the deepest and most lateral portion of the nodule, after which it is moved backward to the most superficial and most medial portion, thereby preventing visual disturbances caused by echogenic bubbles. RFA is terminated when all conceptual units of the targeted nodule have been transformed into transient hyperechoic zones.
Thyroid Ethanol PEI treatment is offered now in the USA.See if you can have this treatment without surgery, neck scar and thyroid hormone treatment by call Matt at 310-393-8860 or firstname.lastname@example.org for details of my evaluation to be treated now in the USA.
Richard Guttler MD,FACE,ECNU