Molecular imaging is pivotal in staging and response assessment of children with neuroblastoma (NB). [ ¹²³ I]-metaiodobenzylguanidine (mIBG) is the standard imaging method; however, it is characterised by low spatial resolution, time-consuming acquisition procedures and difficult interpretation. Many PET catecholaminergic radiotracers have been proposed as a replacement for [ ¹²³ I]-mIBG, however they have not yet made it into clinical practice. We aimed to review the available literature comparing head-to-head [ ¹²³ I]-mIBG with the most common PET catecholaminergic radiopharmaceuticals.
We searched the PubMed database for studies performing a head-to-head comparison between [ ¹²³ I]-mIBG and PET radiopharmaceuticals including meta-hydroxyephedrine ([ ¹¹ C]C-HED), ¹⁸ F-18F-3,4-dihydroxyphenylalanine ([ ¹⁸ F]DOPA) [ ¹²⁴ I]mIBG and Meta-[18F]fluorobenzylguanidine ([ ¹⁸ F]mFBG). Review articles, preclinical studies, small case series (< 5 subjects), case reports, and articles not in English were excluded. From each study, the following characteristics were extracted: bibliographic information, technical parameters, and the sensitivity of the procedure according to a patient-based analysis (PBA) and a lesion-based analysis (LBA).
Ten studies were selected: two regarding [ ¹¹ C]C-HED, four [ ¹⁸ F]DOPA, one [ ¹²⁴ I]mIBG, and three [ ¹⁸ F]mFBG. These studies included 181 patients (range 5-46). For the PBA, the superiority of the PET method was reported in two out of ten studies (both using [ ¹⁸ F]DOPA). For LBA, PET detected significantly more lesions than scintigraphy in seven out of ten studies.
PET/CT using catecholaminergic tracers shows superior diagnostic performance than mIBG scintigraphy. However, it is still unknown if such superiority can influence clinical decision-making. Nonetheless, the PET examination appears promising for clinical practice as it offers faster image acquisition, less need for sedation, and a single-day examination.