Chapter 8 - Molecular Imaging in Neuroblastoma

Abstract

Neuroblastoma is the most common malignancy in infancy and the most common extracranial solid tumor in the pediatric age group. There is only approximately 30%–40% long-term survival rates among the high-risk group. But low-risk and intermediate-risk groups have survival rate more than 90% if given early staging and appropriate therapy. Being embryonal neoplasm, it originates from the precursors of the sympathetic nervous system. Neuroblastoma mostly presented as an abdominal mass, and high urinary levels of catecholamines is noted in almost all cases. Many clinical and imaging investigations are required for evaluation of the disease status. Ultrasonography (USG) should be done in all suspected cases of abdominal neuroblastoma. If an intraspinal extension is suspected, a magnetic resonance (MR) should be performed. This tumor encases vessels and also metastatic spread is common, unlike other solid tumors. Metaiodobenzylguanidine (I-123 MIBG) is among initial molecular imaging agents. Most of the tumor shows MIBG uptake in its primary site as well as metastatic sites. Single photon emission computed tomography (SPECT) alone, or with computed tomography (CT), helps in better localization than planar images. The methylene diphosphonate (MDP) bone scan is used to evaluate cortical bone metastasis. Bone marrow cytology is used to evaluate marrow metastasis. However, fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT showed promising results in an assessment of marrow sites, as well as other metastatic lesions. Functional imaging helps in the prognosis of the disease, further response assessment from therapy, and also monitoring the recurrence. Nuclear medicine techniques are now an essential part of neuroblastoma management.