Endocrine Abstracts

High-intensity focused ultrasound ablation (HIFU) was used in the treatment of thyroid nodules using the device “Echopulse” (Theraclion, France). The therapeutic sensor is represented by a piezoelectric lens with a diameter of 12 cm, with a variable radiation frequency from 0.8 to 1.6 MHz. The treatment was carried out automatically after preliminary planning. The impact zone (ablation focus) was marked automatically on the device screen. The limitations for using HIFU were evaluated. It was found that the localization of the thyroid node is important. Optimal is the presence of a layer of healthy thyroid tissue between the treatment area and the adjacent structures and organs of the neck. The most favorable is the central location of the node and the size of 15–25 mm in diameter. Of the local constraints, the following are marked. There are limitations in performing HIFU in people with short, thick necks and partially retrosternal nodules (cervical-mediastinal goiter) due to the complex and time-consuming positioning of the lens. HIFU application in the event that the thyroid node contour is located close to the trachea, carotid artery and esophagus is difficult, the HIFU program will automatically exclude this area from the ablation zone. With HIFU, the distance to the carotid artery should be more than 4.5 mm (especially if the carotid artery is behind the focal point), and the distance to the trachea should be more than 5 mm (if the trachea is behind the focal point, then more than 10 mm). There are also restrictions for HIFU subcapsular nodes: the depth of the leading edge of the node should not be less than 5.0 mm, the depth of the trailing edge of the node should not be more than 26.7 mm. When selecting patients, the volume of the liquid component was taken into account, HIFU is ineffective in cystic nodules, since the ultrasound energy is not focused in the liquid. A contraindication is the detection of calcifications of various sizes. Macrocalcinosis interferes with the effect of HIFU. There are also limitations in identifying large hyperechoic areas with reduced vascularization (signs of a pronounced fibrous component). Common contraindications for performing HIFU that are not related to thyroid pathology are: Mental instability of the patient. Pacemakers and pacemakers are installed. Recurrent neural abnormalities on the opposite side of the HIFU exposure side. The presence of scars and pigmented nevi in the area of placement of the therapeutic lens.