Multimodal magnetic resonance imaging in neuroblastoma chemotherapy: a narrative review

Neuroblastoma (NB) is a very heterogeneous childhood cancer with its own problems in both the treatment and the assessment of therapeutical responses. The current study has identified the recent application of multimodal magnetic resonance imaging (MRI) in measuring efficacy of chemotherapy in NB. The typical conventional MRI is based on the alteration in tumor size and signal density, however, it is affected by tissue changes caused by post-chemotherapy processes like necrosis and fibrosis, which degrades its accuracy. Diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM) represent advanced functional MRI techniques that provide quantitative information regarding cellular density, water diffusion, and microcirculation perfusion and, therefore, can be used to early measure tumor responses. The apparent diffusion coefficient (ADC) of diffusion mode is linked to tumor differentiation and tumor therapy outcomes, where increasing values of the ADC following chemotherapy are an indicator of positive response. Dynamic contrast-enhanced MRI (DCE-MRI) further adds value to testing by measuring the changes in hemodynamics. Although these benefits exist, issues still exist such as the necessity to implement uniform imaging guidelines, ensure parameter repeatability and sample size limitations. This narrative review is intended to provide clinicians and researchers with a comprehensive overview of the current evidence and to propose future directions for prospective multicenter studies. Multimodal MRI, as a non-invasive tool, plays a crucial role in assessing the response, stratifying the risk, and individualizing treatment plans for neuroblastoma.Combination of structural, functional, and metabolic MRI information promises to improve the diagnostic accuracy and prognostic accuracy in pediatric cancer.