Utility of 18F-FDG PET-CT in pediatric neuroblastoma: Comparison with 131I-MIBG scintigraphy

Objectives To evaluate the utility of 18F-FDG PET-CT in patients with pediatric neuroblastoma and compare the results with that of 131I-MIBG scintigraphy.

Methods Data of 40 patients (age: 5.5+5.6 yrs; male: 32, female: 8) with histopathology proven neuroblastoma who underwent 18F-FDG PET-CT (staging-21, restaging-19) was retrospectively evaluated. 131I-MIBG scintigraphy was available for 28/40 patients (mean interval 15 days). 131I-MIBG scintigraphy and 18F-FDG PET-CT images were independently evaluated by two nuclear medicine physicians and in separate sessions 1 week apart to minimize recall bias. Histopathology (n=50 lesions) and/or clinical/imaging follow-up (n=90 lesions) were taken as reference standard.

Results Patient wise sensitivity, specificity, PPV, NPV and accuracy of 18F-FDG PET-CT were 100%, 50%, 91.89%, 100% and 92.50% respectively. A total of 140 lesions (primary-37, lymph node-31, bone-50, bone marrow-15, and others-7) were detected on 18F-FDG PET-CT in 40 patients. In 28 patients undergoing both the modalities, sensitivity, specificity, PPV, NPV and accuracy of 18F-FDG PET-CT were 100%, 60%, 92%, 100% and 92.80%, respectively and that of 131I-MIBG were 95.65%, 60%, 91.67%, 75% and 89.20% respectively. In these 28 patients, 18F-FDG PET-CT detected 107 lesions (primary-25, lymph node-22, bone/bone marrow-56 and others-4) and 131I-MIBG detected 74 lesions (primary-24, lymph node-5, and bone/bone marrow-45). On patient wise comparison there was no significant difference between 18F-FDG PET-CT and 131I-MIBG (P=1.000), but 18F-FDG PET-CT detected more lesions than 131I-MIBG (P<0.0001). While no difference was noted for primary lesion (P=1.000), PET-CT was significantly better than 131I-MIBG scintigraphy for the detection of lymph nodal (P=0.001) and bone/bone marrow lesions (P=0.007).

Conclusions 18F-FDG PET-CT shows high accuracy in patients with neuroblastoma and detects more lesions as compared to 131I-MIBG scintigraphy in such patients.