Neuroblastoma: Imaging Evaluation by Sequential Tc-99m MDP, I-131 MIBG, and Ga-67 Citrate Studies

Publisher Website
Google Scholar
Abstract
Fourteen children with histopathologically confirmed neuroblastoma underwent sequential correlative imaging studies using I-131 MIBG, Tc-99m MDP, and Ga-67 citrate during various stages of the disease. Of the patients 86% showed I-131 MIBG accumulation in the primary tumoral site, whereas 71% showed Tc-99m MDP and 79% Ga-67 citrate uptake. In 86% at least one of the two latter radiopharmaceuticals concentrated in the primary tumor. The use of all three radiopharmaceuticals raised the detection rate to 93%. Of the osseous or extraosseous metastases 100% were detected by Tc-99m MDP studies. The I-131 MIBG studies were positive in 71% of the osseous metastases and in 70% of the extraosseous metastases. No Ga-67 citrate uptake was demonstrated in osseous metastases, although one extraosseous lung metastasis concentrated this radiopharmaceutical. Tc-99m MDP bone imaging was the best method for diagnosing metastatic spread of the disease and for monitoring the results of treatment. Primary tumor uptake was best indicated by I-131 MIBG. Both Ga-67 citrate and I-131 MIBG were superior to Tc-99m MDP with regard to accurately demonstrating the extent of primary tumors. Only Tc-99m MDP indicated the relationship of these tumors to the kidneys and neighboring osseous structures, providing early screening of kidney compression. Ga-67 citrate study was mainly indicated in tumors with catecholamine depletion, which failed to concentrate the other two radiopharmaceuticals. I-131 MIBG proved especially useful in detecting neuroblastoma with negative Tc-99m MDP and Ga-67 citrate studies and also proved to be useful with those cases in which I-131 MIBG was planned for therapy. The following strategy is suggested for evaluating neuroblastoma. Tc-99m MDP imaging should be performed first for simultaneous diagnosis of primary and metastatic neuroblastoma. I-131 MIBG should be used in cases of negative Tc-99m images or in cases planned for therapy with I-131 MIBG. Only in cases showing catecholamine depletion or negative results with the two latter radiopharmaceuticals should Ga-67 citrate be used. Tc-99m MDP imaging should be the study of choice for the follow-up of the diseases.