Comparación entre la PET/TC con 18F-DOPA y la PET/TC con 68Ga-DOTATOC para la localización del paraganglioma maligno extra-adrenal y el feocromocitoma / 68Ga-DOTATOC PET/CT in the localization of metastatic extra-adrenal paraganglioma and pheochromocytoma compared with 18F-DOPA PET/CT

Objetivo: La PET con 18F-fluoro-L-dihidroxifenilalanina (18F-DOPA) ofrece alta sensibilidad y especificidad en el diagnóstico del paraganglioma extraadrenal no maligno (PGL) y el feocromocitoma (FEO), pero menor sensibilidad en la enfermedad metastásica. Estos tumores son de origen neuroendocrino y pueden detectarse mediante PET con 68Ga-DOTA-Tyr3-octreótido (68Ga-DOTA-TOC). Por tanto, comparamos 68Ga-DOTA-TOC y 18F-DOPA como radiotrazadores para PET/TC para el diagnóstico de PGL extradrenal metastásico y FEO. Las imágenes tomográficas anatómicas y funcionales fusionadas se utilizaron como estándar de referencia. Métodos: Se incluyó en el estudio a un total de 6 varones y 4 mujeres (rango de edad de 22 a 72 años), con PGL metastásico y FEO anatómica y/o histológicamente demostrados. De entre estos pacientes, 2 varones padecían FEO y los 8 pacientes restantes PGL extraadrenal metastásico. La evaluación comparativa incluyó imagen morfológica con TC e imagen funcional mediante PET con 68Ga-DOTA-TOC y 18F-DOPA. Se analizaron los resultados de las imágenes por lesión. Se midió el valor máximo de captación estandarizado (SUVmáx) de cada modalidad de imagen funcional en las lesiones tumorales concordantes. Resultados: En comparación con la imagen anatómica, la tasa de detección por lesión mediante PET con 68Ga-DOTA-TOC fue del 100% (McNemar, p<0,01), y la de PET con 18F-DOPA fue del 82,3% (McNemar, p<0,8) para PGL extraadrenal metastásico y FEO. En general, la PET con 68Ga-DOTA-TOC identificó 67 lesiones, la imagen anatómica identificó 62 lesiones y la PET con 18F-DOPA identificó 56 lesiones. El valor SUVmáx (media±DE) de todas las lesiones concordantes fue de 29,3±19,9 para la PET con 68Ga-DOTA-TOC, y de 12,3±9,1 para la PET con 18F-DOPA (prueba U de Mann-Whitney, p<0,0001). Conclusión: La PET con 68Ga-DOTA-TOC proporciona un índice de detección más elevado en el PGL extra-adrenal metastásico y PHEO, en comparación con la PET con 18F-DOPA, e incluso con la TC diagnóstica, particularmente en lo referente a lesiones óseas. La imagen funcional/anatómica combinada (PET/TC con 68Ga-DOTA-TOC) permite detectar la extensión exacta del tumor en estas entidades tumorales infrecuentes, especialmente en caso de correlación anatómica incierta

Objective: 18F-Fluoro-L-dihydroxyphenylalanine (18F-DOPA) PET offers high sensitivity and specificity in the imaging of non-malignant extra-adrenal paraganglioma (PGL) and pheochromocytoma (PHEO) but lower sensitivity in metastatic disease. These tumours are of neuroendocrine origin and can be detected by 68Ga-DOTA-Tyr3-octreotide (68Ga-DOTA-TOC) PET. Therefore, we compared 68Ga-DOTA-TOC and 18F-DOPA as radiolabels for PET/CT imaging for the diagnosis of metastatic extra-adrenal PGL and PHEO. Combined cross-sectional imaging was the reference standard. Methods: A total of 6 men and 4 women (age range 22-72 years) with anatomical and/or histologically proven metastatic PGL and PHEO were included in this study. Of these patients, 2 male patients suffered from PHEO, while the remaining 8 patients were diagnosed as metastatic extra-adrenal PGL disease. Comparative evaluation included morphological imaging with CT and functional imaging with 68Ga-DOTA-TOC and 18F-DOPA PET. The imaging results were analyzed on a per-lesion basis. The maximum standardized uptake value (SUVmax) of each functional imaging modality in concordant tumour lesions was measured. Results: Compared with anatomical imaging, the per-lesion detection rate of 68Ga-DOTA-TOC was 100% (McNemar, P<0.01), and that of 18F-DOPA PET was 82.3% (McNemar, P<0.8) in metastatic extra-adrenal PGL and PHEO. Overall, 68Ga-DOTA-TOC PET identified 67 lesions; anatomical imaging identified 62 lesions, and 18F-DOPA PET identified 56 lesions. The SUVmax (mean±SD) of all concordant lesions was 29.3±19.9 for 68Ga-DOTA-TOC PET and 12.3±9.1 for 18F-DOPA PET (Mann-Whitney U test, P<0.0001). Conclusion: 68Ga-DOTA-TOC PET offers the highest detection rate in metastatic extra-adrenal PGL and PHEO compared to 18F-DOPA PET and even to diagnostic CT, particularly in bone lesions. Combined functional/anatomical imaging (68Ga-DOTA-TOC PET/CT) enables exact tumour extension to be detected in these rare tumour entities, especially in the case of unclear anatomical correlation

68Ga-DOTATOC PET/CT in the localization of metastatic extra-adrenal paraganglioma and pheochromocytoma compared with 18F-DOPA PET/CT. / Comparación entre la PET/TC con 18F-DOPA y la PET/TC con 68Ga-DOTATOC para la localización del paraganglioma maligno extra-adrenal y el feocromocitoma.

OBJECTIVE: 18F-Fluoro-L-dihydroxyphenylalanine (18F-DOPA) PET offers high sensitivity and specificity in the imaging of non-malignant extra-adrenal paraganglioma (PGL) and pheochromocytoma (PHEO) but lower sensitivity in metastatic disease. These tumours are of neuroendocrine origin and can be detected by 68Ga-DOTA-Tyr3-octreotide (68Ga-DOTA-TOC) PET. Therefore, we compared 68Ga-DOTA-TOC and 18F-DOPA as radiolabels for PET/CT imaging for the diagnosis of metastatic extra-adrenal PGL and PHEO. Combined cross-sectional imaging was the reference standard. METHODS: A total of 6 men and 4 women (age range 22-72 years) with anatomical and/or histologically proven metastatic PGL and PHEO were included in this study. Of these patients, 2 male patients suffered from PHEO, while the remaining 8 patients were diagnosed as metastatic extra-adrenal PGL disease. Comparative evaluation included morphological imaging with CT and functional imaging with 68Ga-DOTA-TOC and 18F-DOPA PET. The imaging results were analyzed on a per-lesion basis. The maximum standardized uptake value (SUVmax) of each functional imaging modality in concordant tumour lesions was measured. RESULTS: Compared with anatomical imaging, the per-lesion detection rate of 68Ga-DOTA-TOC was 100% (McNemar, P<0.01), and that of 18F-DOPA PET was 82.3% (McNemar, P<0.8) in metastatic extra-adrenal PGL and PHEO. Overall, 68Ga-DOTA-TOC PET identified 67 lesions; anatomical imaging identified 62 lesions, and 18F-DOPA PET identified 56 lesions. The SUVmax (mean±SD) of all concordant lesions was 29.3±19.9 for 68Ga-DOTA-TOC PET and 12.3±9.1 for 18F-DOPA PET (Mann-Whitney U test, P<0.0001). CONCLUSION: 68Ga-DOTA-TOC PET offers the highest detection rate in metastatic extra-adrenal PGL and PHEO compared to 18F-DOPA PET and even to diagnostic CT, particularly in bone lesions. Combined functional/anatomical imaging (68Ga-DOTA-TOC PET/CT) enables exact tumour extension to be detected in these rare tumour entities, especially in the case of unclear anatomical correlation.