Comparison of 18F-dopa PET/CT and 123I-MIBG scintigraphy in stage 3 and 4 neuroblastoma: a pilot study.

Purpose: (18)F-Dopa positron emission tomography (PET)/CT has proved a valuable tool for the assessment of neuroendocrine tumours. So far no data are available on (18)F-dopa utilization in neuroblastoma (NB). Our aim was to evaluate the role of (18)F-dopa PET/CT in NB and compare its diagnostic value with that of (123)I-metaiodobenzylguanidine (MIBG) scintigraphy in patients affected by stage 3-4 NB.

Methods: We prospectively evaluated 28 paired (123)I-MIBG and (18)F-dopa PET/CT scans in 19 patients: 4 at the time of the NB diagnosis and 15 when NB relapse was suspected. For both imaging modalities we performed a scan-based and a lesion-based analysis and calculated sensitivity, specificity and accuracy. The standard of reference was based on clinical, imaging and histological data.

Results: NB localizations were confirmed in 17 of 19 patients. (18)F-Dopa PET/CT and (123)I-MIBG scintigraphy properly detected disease in 16 (94%) and 11 (65%), respectively. On scan-based analysis, (18)F-dopa PET/CT showed a sensitivity and accuracy of 95 and 96%, respectively, while (123)I-MIBG scanning showed a sensitivity and accuracy of 68 and 64%, respectively (p < 0.05). No significant difference in terms of specificity was found. In 9 of 28 paired scans (32%) PET/CT results influenced the patient management. We identified 156 NB localizations, 141 of which were correctly detected by (18)F-dopa PET/CT and 88 by MIBG. On lesion-based analysis, (18)F-dopa PET/CT showed a sensitivity and accuracy of 90% whereas (123)I-MIBG scintigraphy showed a sensitivity and accuracy of 56 and 57%, respectively (p < 0.001). No significant difference in terms of specificity was found.

Conclusion: In our NB population (18)F-dopa PET/CT displayed higher overall accuracy than (123)I-MIBG scintigraphy. Consequently, we suggest (18)F-dopa PET/CT as a new opportunity for NB assessment.