Usefulness of Doppler ultrasound-obtained resistance index in thyroid nodules with ultrasonographic malignant characteristics

Abstract

espanolIntroduccion: La patologia nodular tiroidea tiene alta prevalencia en la poblacion general. Su diagnostico se ha incrementado con el Doppler, con el cual se pueden detectar caracteristicas sugerentes de malignidad, como elevacion de los indices de resistencia y pulsatilidad. Objetivo: Evaluar la correlacion de un indice de resistencia alto y los hallazgos histopatologicos en pacientes con sospecha ecografica de nodulos tiroideos malignos. Metodo: Estudio prospectivo, observacional, transversal y analitico de pruebas diagnosticas, en el Hospital de Especialidades 25, Monterrey, Nuevo Leon. Se incluyo a pacientes con nodulos tiroideos de caracteristicas ecograficas malignas; se obtuvo el indice de resistencia de los nodulos, que se comparo con los hallazgos histopatologicos. Resultados: Se incluyeron 48 pacientes con diagnostico ecografico de nodulo tiroideo maligno. La correlacion de indices de resistencia elevados y diagnostico histopatologico de nodulos tiroideos malignos fue significativa (p = 0.001). La sensibilidad fue de 73.3 %, y la especificidad de 78.7 %; valor predictivo positivo de 61.1 % y valor predictivo positivo negativo de 86.6 %. Conclusion: La determinacion del indice de resistencia cada vez es mas empleada, pero la sensibilidad y especificidad es baja y no es un metodo confiable, por lo que aun se requieren otros metodos complementarios. EnglishIntroduction: Thyroid nodular disease is highly prevalent in the general population. Its diagnosis has increased with Doppler ultrasound, by means of which features suggestive of malignancy can be detected, such as resistance and pulsatility indices elevation. Objective: To assess the correlation of a high resistance index and histopathological findings in patients with ultrasonographic suspicion of malignant thyroid nodules. Method: Prospective, cross-sectional, analytic, observational study of diagnostic tests carried out at Specialty Hospital 25, in Monterrey, Nuevo Leon. Patients with thyroid nodules of ultrasonographic malignant characteristics were included; the resistance index of the nodules was obtained and compared with histopathological findings. Results: Forty-eight patients with ultrasonographic diagnosis of malignant nodules were included. The correlation of elevated resistance indices with malignant thyroid nodule histopathologic diagnosis was significant (p = 0.001). Sensitivity was 73.3% and specificity 78.7%; positive predictive value was 61.1% and negative predictive value was 86.6%. Conclusion: The resistance index determination is increasingly being used, but its sensitivity and specificity are low, and it is not a reliable method, and other complementary methods are therefore still required.