Skeletal assessment in neuroblastoma--the pitfalls of iodine-123-MIBG scans

This study was carried out to compare iodine-123 metaiodobenzylguanidine ((I123I)MIBG) and technetium-99m-methylene diphosphonate bone scans ({sup 99m}Tc-MDP) in the detection of skeletal involvement by neuroblastoma. Forty-four children with neuroblastoma underwent both ({sup 123}I) MIBG and {sup 99m}Tc-MDP scans within a 4-wk period; bone marrow examination also was performed; all these investigations were done both at diagnosis and at follow-up. At diagnosis, four children with Stage 4 disease had normal ({sup 123}I)MIBG scans but abnormal {sup 99m}Tc-MDP scans, while at follow-up there were four children with negative ({sup 123}I)MIBG studies who later died from disseminated neuroblastoma. All eight scans are considered false-negative. In 24 children, the ({sup 123}I)MIBG revealed more extensive disease with 161 positive sites while the {sup 99m}Tc-MDP scan showed only 100 positive sites; 34 of these sites were common to both studies. This study shows that underassessment of skeletal involvement by neuroblastoma occurred using ({sup 123}I)MIBG scans and that one cannot therefore substitute ({sup 123}I)MIBG for {sup 99m}Tc-MDP bone scans in the staging of neuroblastoma.