123I-MIBG scintigraphy and 18F-FDG PET in neuroblastoma

The purpose of this study was to compare the diagnostic utility of (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy and (18)F-FDG PET in neuroblastoma.

A total of 113 paired (123)I-MIBG and (18)F-FDG PET scans in 60 patients with neuroblastoma were retrospectively reviewed. Paired scans were acquired within 14 days of each other.

For stage 1 and 2 neuroblastoma (13 scans, 10 patients), (18)F-FDG depicted more extensive primary or residual neuroblastoma in 9 of 13 scans. (123)I-MIBG and (18)F-FDG showed equal numbers of lesions in 1 of 13 scans, and 3 of 13 scan results were normal. For stage 3 neuroblastoma (15 scans, 10 patients), (123)I-MIBG depicted more extensive primary neuroblastoma or local or regional metastases in 5 of 15 scans. (18)F-FDG depicted more extensive primary neuroblastoma or local or regional metastases in 4 of 15 scans. (123)I-MIBG and (18)F-FDG were equal in 2 of 15 scans, and 4 of 15 scan results were normal. For stage 4 neuroblastoma (85 scans, 40 patients), (123)I-MIBG depicted more neuroblastoma sites in 44 of 85 scans. (18)F-FDG depicted more neuroblastoma sites in 11 of 85 scans. (123)I-MIBG and (18)F-FDG were equivalent or complementary in 13 of 85 scans, and 17 of 85 scan results were normal.

(18)F-FDG is superior in depicting stage 1 and 2 neuroblastoma, although (123)I-MIBG may be needed to exclude higher-stage disease. (18)F-FDG also provides important information for patients with tumors that weakly accumulate (123)I-MIBG and at major decision points during therapy (i.e., before stem cell transplantation or before surgery). (18)F-FDG can also better delineate disease extent in the chest, abdomen, and pelvis. (123)I-MIBG is overall superior in the evaluation of stage 4 neuroblastoma, especially during initial chemotherapy, primarily because of the better detection of bone or marrow metastases.