RESUMEN
PURPOSE: The aim of this study is to evaluate structural alterations of thyroid tissue after microwave ablation using elastography and scintigraphic imaging to investigate the applicability of these diagnostic methods for follow-up.â MATERIALS AND METHODS: 35 patients with 39 thyroid nodules were evaluated using elastography and scintigraphic imaging before and after ultrasound-guided microwave ablation. Elastography was analyzed according to color-coded output and results were classified using a fourfold elasticity score (ES). Nodules color-coded blue were classified ES1 for high elasticity through ES2 and ES3 for lower elasticity, and nodules with very low elasticity were color-coded red and classified as ES4. (99m)Tc-pertechnetate served as a tracer for scintigraphic imaging of hot and indifferent nodules and (99m)Tc-MIBI for cold nodules. RESULTS: Before microwave ablation, elastography detected a median elasticity score of ES 2â±â0.7, and after ablation the median score was ES 3â±â0.6. Overall, the median score increased by 1ES ±â0.6 (pâ<â0.01). Scintigraphic imaging detected a median reduction of tracer uptake in ablated tissue of 38.7â%±â27.5(pâ<â0.01). (99m)Tc-pertechnetate scans showed a median decrease of tracer uptake of 26.3â%±â16.3 and (99m)Tc-MIBI scans detected uptake reduction of 54.7â%±â29.2. CONCLUSION: Scintigraphic imaging using (99m)Tc-pertechnetate and (99m)Tc-MIBI provides quantifiable results and is promising as a diagnostic follow-up after microwave ablation. Strain elastography detects decreasing tissue elasticity, but accuracy is limited by the necessary reduction of color-coded output to elasticity scores.
Asunto(s)
Diagnóstico por Imagen de Elasticidad/métodos , Electrocoagulación/métodos , Hipertermia Inducida/métodos , Microondas/uso terapéutico , Cintigrafía/métodos , Nódulo Tiroideo/diagnóstico , Nódulo Tiroideo/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radiofármacos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Tecnecio Tc 99m Sestamibi , Resultado del TratamientoRESUMEN
UNLABELLED: Microwave ablation (MWA) is a new minimal invasive method for thermal ablation of benign thyroid nodules. In contrast to well-established radiofrequency ablation (RFA), MWA offers several advantages with similarly successful results. There has not been any use of functional imaging with 99mTc-pertechnetate and 99mTc-MIBI-scans as a mere qualitative analysis of this imaging in the field of MWA in Europe until now. The aim of this study has been to demonstrate the feasibility of MWA as well as the applicability of functional imaging to verify effectiveness with a centerspecific score. PATIENTS, METHODS: 11 patients (5 women, 6 men, average age 62.3 years) with 18 benign thyroid nodules were treated. MWA was operated under local anesthesia with a system working in a wavelength field of 902 to 928 MHz (Avecure MWG881, MedWaves, Inc. San Diego, CA). Pre- and postablative scans were controlled by two specialists in nuclear medicine with longtime work experience. RESULTS: A center specific functional imaging score (CSFIS) was defined, a decrease of 1.4 points at an average was noticeable (range 1-3 points). In 66.7% (n = 12) of all nodules the score decreased by 1 point, 27.8% (n = 5) by 2 points and 5.6% (n = 1) by 3 points. The treatment was well tolerated and no severe complications were observed. CONCLUSION: The preliminary data suggests that MWA is an effective method to treat benign thyroid nodules. Functional imaging is a promising technique for early verification of effectiveness of thermal ablation.