The evidence-based role of catecholaminergic PET tracers in Neuroblastoma. A systematic review and a head-to-head comparison with mIBG scintigraphy

Abstract

Background: Molecular imaging is pivotal in staging and response assessment of children with neuroblastoma (NB). [¹²³I]-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 [¹²³I]-mIBG, however they have not yet made it into clinical practice. We aimed to review the available literature comparing head-to-head [¹²³I]-mIBG with the most common PET catecholaminergic radiopharmaceuticals.

Methods: We searched the PubMed database for studies performing a head-to-head comparison between [¹²³I]-mIBG and PET radiopharmaceuticals including meta-hydroxyephedrine ([¹¹C]C-HED), ¹⁸F-18F-3,4-dihydroxyphenylalanine ([¹⁸F]DOPA) [¹²⁴I]mIBG and Meta-[18F]fluorobenzylguanidine ([¹⁸F]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).

Results: Ten studies were selected: two regarding [¹¹C]C-HED, four [¹⁸F]DOPA, one [¹²⁴I]mIBG, and three [¹⁸F]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 [¹⁸F]DOPA). For LBA, PET detected significantly more lesions than scintigraphy in seven out of ten studies.

Conclusions: 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.

Keywords: Catecholamine; Guideline; Neuroblastoma; PET-CT; Paediatric PET; [124I]MIBG, 18F-MFBG, 11C-HED; [18F]F-DOPA.

Fig. 1

PRISMA flowchart indicating the selection process of the included studies

Fig. 2

Therapy response evaluation of a 4-year-old boy with high-risk neuroblastoma. [¹²³I]mIBG whole-body scan (left panel). Maximum intensity projection (MIP) of [.¹⁸F]mFBG PET (right panel). Pathological uptake in primary abdominal neuroblastoma and extensive osteomedullary neuroblastoma localisations on both investigations, more clearly and with higher resolution depicted with [18F]mFBG PET. [18F]mFBG PET also detected additional mediastinal lymph node metastases (arrows)

Fig. 3

Sixteen-year-old boy affected by NB bone relapse. [¹²³I] mIBG whole-body scan and SPECT/CT (planar and axial images) showed multiple bone localisations (left panels). In the same patients [¹⁸F]DOPA, maximum intensity projection (MIP) and axial images showed many small additional lesions (right panels, arrows)