RESUMO
We present the case of a 57-year old woman diagnosed of papillary thyroid carcinoma and treated with thyroidectomy followed by radioiodine (I-131) on two occasions. Follow-up radioiodine scan showed disease in right cervical region, confirmed by fine needle aspiration (FNA) and treated with lymphadenectomy. Due to thyroglobulin elevation, I-131 scan negative and inconclusive cervical ultrasonography/CT scan, we conducted a CT/PET study that confirmed cervical disease. An additional CT scan that was performed on maximum-inspiration showed four micro-nodules, one of which was not detected by the CT scan on shallow breathing (CT/PET). Post-treatment (I-131) scan confirmed uptake in these localizations. Good fusion between PET and CT images that avoids the errors of attenuation correction, especially in the lung bases, is necessary for correct image interpretation of the CT/PET study. Shallow breathing is necessary in order to obtain optimal image fusion with the CT/PET study, although this is not the best to evaluate pulmonary parenchyma in which an additional inspiratory CT scan improves detection of the pulmonary nodules.
Assuntos
Tomografia por Emissão de Pósitrons , Nódulo Pulmonar Solitário/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Feminino , Humanos , Inalação , Pessoa de Meia-IdadeRESUMO
Presentamos el caso de una mujer de 57 años diagnosticada de carcinoma papilar de tiroides, tratada con tiroidectomía y radioyodo en dos ocasiones. Un rastreo de control muestra captación cervical derecha, confirmada por punción aspiración con aguja fina, tratada con linfadenectomía. Ante la elevación de tiroglobulina, el rastreo negativo y la ecografía/TC cervical inespecífica se realiza un estudio tomográfico por emisión de positrones/tomográfico computarizado (PET/TC) que confirma infiltración del lecho cervical. Adicionalmente se le realiza una TC en máxima inspiración que muestra cuatro micronódulos, uno de ellos no detectado por la TC del estudio PET/TC. El rastreo posterapéutico (I-131) confirma captación en estas localizaciones. Para la correcta interpretación de las imágenes PET/TC se necesita una fusión óptima de la PET y la TC, que minimice errores de corrección de atenuación, especialmente en las bases pulmonares. La fusión más óptima se consigue en respiración suave, aunque no es la más adecuada para la evaluación del parénquima pulmonar, para la que es necesaria realizar una segunda TC en máxima inspiración
We present the case of a 57-year old woman diagnosed of papillary thyroid carcinoma and treated with thyroidectomy followed by radioiodine (I-131) on two occasions. Follow-up radioiodine scan showed disease in right cervical region, confirmed by fine needle aspiration (FNA) and treated with lymphadenectomy. Due to thyroglobulin elevation, I-131 scan negative and inconclusive cervical ultrasonography/CT scan, we conducted a CT/PET study that confirmed cervical disease. An additional CT scan that was performed on maximum-inspiration showed four micro-nodules, one of which was not detected by the CT scan on shallow breathing (CT/PET). Post-treatment (I-131) scan confirmed uptake in these localizations. Good fusion between PET and CT images that avoids the errors of attenuation correction, especially in the lung bases, is necessary for correct image interpretation of the CT/PET study. Shallow breathing is necessary in order to obtain optimal image fusion with the CT/PET study, although this is not the best to evaluate pulmonary parenchyma in which an additional inspiratory CT scan improves detection of the pulmonary nodules