RESUMO
PROPÓSITO: La identificación precisa de los gliomas de bajo grado (GBG; grados I y II de la Organización Mundial de la Salud) y su diferenciación de las lesiones por inflamación cerebral (BIL) sigue siendo difícil; sin embargo, es esencial para el tratamiento. Este estudio evaluó si un protocolo de un día para la PET/TC con 18F-FDG y 13N-amonio con análisis de desacoplamiento de la captación podría diferenciar los GBG de las BIL. MATERIALES Y MÉTODOS: Veintiocho pacientes con GBG y 16 pacientes con BIL se sometieron a PET/TC con 18F-FDG y 13N-amonio el mismo día antes de cualquier tipo de terapia. La puntuación de desacoplamiento y la relación tumor/tejido normal (T/N) de 18F-FDG y 13N-amonio se calcularon en cada localización. Se utilizó la prueba t de Student para comparar valores, y el análisis de la curva ROC para establecer un valor de corte para la relación T/N y la puntuación de desacoplamiento. Se calculó el área bajo la curva (AUC) para evaluar la eficacia diferencial. RESULTADOS: Se observaron diferencias significativas en la relación T/N de 13N-amonio (p = 0,018) y en la puntuación de desacoplamiento (p = 0,003) entre los GBG y las BIL; sin embargo, la relación T/N de 18F-FDG no mostró ninguna diferencia (p = 0,413). Los valores de corte óptimos para la relación T/N de 18F-FDG, la relación T/N de 13N-amonio y la puntuación de desacoplamiento fueron 0,73, 0,97 y 2,31, respectivamente, con AUC correspondientes de 0,48, 0,68 y 0,77. Los respectivos parámetros de sensibilidad, especificidad y precisión que utilizan estos valores de corte fueron 53,6%, 62,5% y 56,8%, respectivamente, para 18F-FDG; 50,0%, 75,0% y 59,1%, respectivamente, para 13N-amonio; y 60,7%, 93,8% y 72,7%, respectivamente, para la puntuación de desacoplamiento. CONCLUSIONES: La puntuación de desacoplamiento de la captación de 18F-FDG/13N amonio se puede utilizar para discriminar entre GBG y BIL. El uso de un mapa de desacoplamiento de estos dos trazadores puede mejorar el análisis visual y la precisión del diagnóstico
PURPOSE: Accurate identification of low-grade gliomas (LGGs; World Health Organization grades I and II) and their differentiation from brain inflammation lesions (BILs) remains difficult; however, it is essential for treatment. This study assessed whether a one-day protocol for voxel-wise 18F-FDG and 13N-ammonia PET/CT with uptake decoupling analysis could differentiate LGGs from BILs. MATERIALS AND METHODS: Twenty-eight patients with LGGs and 16 patients with BILs underwent 18F-FDG and 13N-ammonia PET/CT on the same day before any type of therapy. The decoupling score and tumor-to-normal tissue (T/N) ratio of 18F-FDG and 13N-ammonia were calculated at each location. Student's t-test was used to compare values, and ROC curve analysis was used to establish a cut-off value for the T/N ratio and decoupling score. Area under the curve (AUC) was calculated to evaluate differential efficacy. RESULTS: Significant differences were observed in 13N-ammonia T/N ratio (p = 0.018) and decoupling score (p = 0.003) between LGGs and BILs; however, the 18F-FDG T/N ratio did not show any differences (p = 0.413). Optimal cut-off values for 18F-FDG T/N ratio, 13N-ammonia T/N ratio, and decoupling score were 0.73, 0.97, and 2.31, respectively, with corresponding AUCs of 0.48, 0.68, and 0.77. The respective sensitivity, specificity, and accuracy parameters using these cut-off values were 53.6%, 62.5%, and 56.8%, respectively, for 18F-FDG; 50.0%, 75.0%, and 59.1%, respectively, for 13N-ammonia; and 60.7%, 93.8%, and 72.7%, respectively, for decoupling score. CONCLUSIONS: 18F-FDG/13N-ammonia uptake decoupling score can be used to discriminate between LGGs and BILs. Use of a decoupling map of these two tracers can improve visual analysis and diagnostic accuracy
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Neoplasias Encefálicas/diagnóstico por imagem , Encefalite/diagnóstico por imagem , Fluordesoxiglucose F18 , Glioma/diagnóstico por imagem , Radioisótopos de Nitrogênio , Tomografia Computadorizada por Raios X/métodos , Compostos Radiofarmacêuticos , Área Sob a Curva , Cérebro/diagnóstico por imagem , Cérebro/metabolismo , Abscesso Encefálico/diagnóstico por imagem , Abscesso Encefálico/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Doenças Desmielinizantes/diagnóstico por imagem , Doenças Desmielinizantes/metabolismo , Encefalite/metabolismo , Fluordesoxiglucose F18/farmacocinética , Glioma/metabolismo , Glioma/patologia , Gradação de Tumores , Radioisótopos de Nitrogênio/farmacocinética , Tomografia por Emissão de Pósitrons , Curva ROC , Compostos Radiofarmacêuticos/farmacocinética , Estudos Retrospectivos , Sensibilidade e EspecificidadeRESUMO
PURPOSE: Accurate identification of low-grade gliomas (LGGs; World Health Organization grades I and II) and their differentiation from brain inflammation lesions (BILs) remains difficult; however, it is essential for treatment. This study assessed whether a one-day protocol for voxel-wise 18F-FDG and 13N-ammonia PET/CT with uptake decoupling analysis could differentiate LGGs from BILs. MATERIALS AND METHODS: Twenty-eight patients with LGGs and 16 patients with BILs underwent 18F-FDG and 13N-ammonia PET/CT on the same day before any type of therapy. The decoupling score and tumor-to-normal tissue (T/N) ratio of 18F-FDG and 13N-ammonia were calculated at each location. Student's t-test was used to compare values, and ROC curve analysis was used to establish a cut-off value for the T/N ratio and decoupling score. Area under the curve (AUC) was calculated to evaluate differential efficacy. RESULTS: Significant differences were observed in 13N-ammonia T/N ratio (p=0.018) and decoupling score (p=0.003) between LGGs and BILs; however, the 18F-FDG T/N ratio did not show any differences (p=0.413). Optimal cut-off values for 18F-FDG T/N ratio, 13N-ammonia T/N ratio, and decoupling score were 0.73, 0.97, and 2.31, respectively, with corresponding AUCs of 0.48, 0.68, and 0.77. The respective sensitivity, specificity, and accuracy parameters using these cut-off values were 53.6%, 62.5%, and 56.8%, respectively, for 18F-FDG; 50.0%, 75.0%, and 59.1%, respectively, for 13N-ammonia; and 60.7%, 93.8%, and 72.7%, respectively, for decoupling score. CONCLUSIONS: 18F-FDG/13N-ammonia uptake decoupling score can be used to discriminate between LGGs and BILs. Use of a decoupling map of these two tracers can improve visual analysis and diagnostic accuracy.
