Experimental Study And Clinical Application Of Ultrasound-guided Laser Ablation Of Thyroid Benign Nodules

Objective:To obtain the parameters of ultrasound-guided (US) laser ablation (LA) of ex vivo porcine thyroid, such as ablation shape, scope and temperature rise curve, using different output powers and different energy, to evaluate the effectiveness, safety, feasibility of laser ablation, and then determine the best ablation output powers and total energy for thyroid tissue, providing reference for the clinical application of laser ablation thyroid nodules.Materials and Methods:Echo Laser X4integrated laser interventional ultrasound system was used to ablate fresh porcine thyroid. Ultrasound-guided laser ablations were induced by using different output powers (1W,2W,3W,4W,5W,6W,7W) and different energy (300J、600J、900J、1200J、1500J、1800J). Thermocouple was used to be inserted in the tissue0-,5-,10-and15-mm from the fiber tip at the same time of ablation to measure the temperature in real time. Histopathological examination confirmed the ablation effect of ablated tissue after laser ablation; and the ablation conditions in each group were compared.Results:The shape of the ablation zone is roughly is ellipse. The ultrasound shows strong echo area in the center, slightly strong echo in the peripheral tissue and posterior echo attenuation. After dissection, the naked eye observation the center of ablation lesions is cavity surrounded slag-like carbonized tissue; the peripheral is white or yellowish necrosis area. HE staining showed:the center of ablation lesion is irregular oval cavity and almost no dye stained. Around the cavity, a thin carbonized layer is observed; the peripheral tissue is coagulation necrosis of the thyroid follicular. The light microscopy showed:central is "empty", a reduction of thyroid follicle in the necrosis, with the follicular epithelium contracted and the epithelium cell nucleus solidified obviously. Temperature displayed:all the temperatures measured at optical fiber0-,5-mm exceeds60℃in greater than or equal to2W groups. Statistical results show:the output power at3W and the total energy1200-1800J, the differences of ablated area has statistical significance (P<0.05).Conclusion:Ultrasound-guided laser ablation of the porcine thyroid is well safe, definitely effective; the size of ablation lesions is stable. The ablation lesions increase as the output power and energy increases. The experimental results demonstrated:when the laser output power at3W and energy1200-1800J, the ablation effect reaches best effect. Figure8, table2,28references. Background:Laser ablation (LA) is a minimally invasive treatment method developed in recent years, there are many reports in the literature about laser ablation at present, but few about laser ablation of thyroid nodules treatment that completely cured.Objective:The aim to through ultrasound-guided (US) laser ablation of thyroid benign nodules, to investigate the feasibility, the safety and the clinical value of ultrasound-guided percutaneous laser ablation (PLA) of benign thyroid nodules.Materials and Methods:Ultrasound-guided laser ablation was performed in90patients with118benign thyroid nodules from September2012to April2014in our hospital. Routine assays of thyroid function were performed and the clinical symptoms were evaluated at preoperative. And we adopted conventional ultrasound (CUS) and contrast-enhanced ultrasound (CEUS) to assess of all the thyroid nodules size and enhancement. Laser ablation power is set at3W. Ablation method according to the nodules size and then make decisions to adopt a single or multi-needle multi-point ablation. CEUS was performed on nodules1day after ablation to evaluate completely ablation conditions. Thyroid nodules volume, thyroid function, clinical symptoms and complications were evaluated at1,3,6,12, and18follow-up period after the procedure. The study was approved by the ethics committee of our hospital; all patients were informed consent and signed a written informed consent.Results:All the benign thyroid nodules were successful conducted laser ablation. The nodules largest diameter≤1cm,≤2cm and>2cm, the completely ablated rate in an ablation was97.1%,91.2%,62.5%, respectively. CUS follow-up at postoperative and all the nodules volume decreased significantly compared to1day after LA (P<0.05), the largest diameter decreased from1.01±0.64cm to0.83±0.56cm, and the volume decreased from0.30±0.37ml to0.17±0.20ml (P<0.05), the volume reduction ratio (VRR) was71.8% at the final time evaluation. And25.4%(30/118) nodules completely disappeared after12months. Thyroid function was not significantly different before treatment and after lmonth (P>0.05). Laser ablation treatment was well tolerated; three patients had strong pain in procedure. One patient (1.1%) had experienced recurrent laryngeal nerve injury and was recovered within6months after treatment.Conclusions:Ultrasound-guided laser ablation can be effectively inactivated benign thyroid nodules, especially suitable for<2cm benign thyroid nodules. It is a good cosmetic effect, very safe, effective and potentially feasible minimally invasive treatment technology. Laser ablation is a safe, effective and potential feasible minimally invasive technique for thyroid nodules. LA is expected to become an important supplement to the surgical operation of benign thyroid nodules.Figure9, table2,27references.