Efficacy of Metaiodobenzylguanidine As a Scintigraphic Agent for the Detection of Neuroblastoma

Rationale And Objectives: Metaiodobenzylguanidine (MIBG) has been shown to be both sensitive and highly specific for the detection of neuroblastoma. However, controversy surrounds its sensitivity in detecting neuroblastoma when compared with radionuclide (technetium 99m-methylene diphosphonate [99mTc]-MDP) bone scans. Because a diagnostic test ideally should be easy to interpret in addition to being sensitive and specific, this study aims to determine the most efficacious scintigraphic agent for diagnostic use in neuroblastoma.

Methods: Twenty patients with neuroblastoma had a total of 26 paired MIBG and 99mTc-MDP bone scans obtained less than 4 weeks apart. Each study was evaluated independently of its counterpart by six separate observers (3 experienced and 3 inexperienced in MIBG scintigraphy) to determine the presence or absence of disease and the tumor burden.

Results: Inexperienced observers reported more confidence in their interpretations of 99mTc-MDP bone scans; however, seven false-positive bone scans were reported. Using MIBG, all true-positive and true-negative scans, as well as significantly more sites of both primary and metastatic disease, were identified by all observers.

Conclusion: This study suggests that MIBG is the more efficacious agent for the scintigraphic evaluation of neuroblastoma.