Perfusion imaging of neuroblastoma and nephroblastoma in a paediatric population using pseudo-continuous arterial spin-labelling magnetic resonance imaging

Objectives To examine the feasibility of performing ASL-MRI in paediatric patients with solid abdominal tumours. Methods Multi-delay ASL data sets were acquired in ten paediatric patients diagnosed with either a neuroblastoma (n = 4) or nephroblastoma (n = 6) during a diagnostic MRI examination at a single visit (n = 4 at initial staging, n = 2 neuroblastoma and n = 2 nephroblastoma patients; n = 6 during follow-up, n = 2 neuroblastoma and n = 4 nephroblastoma patients). Visual evaluation and region-of-interest (ROI) analyses were performed on the processed perfusion-weighted images to assess ASL perfusion signal dynamics in the whole tumour, contralateral kidney, and tumour sub-regions with/without contrast enhancement. Results The majority of the included abdominal tumours presented with relatively low perfusion-weighted signal (PWS), especially compared with the highly perfused kidneys. Within the tumours, regions with high PWS were observed which, at short PLD, are possibly related to labelled blood inside vessels and at long PLD, reflect labelled blood accumulating inside tumour tissue over time. Conversely, comparison of ASL perfusion-weighted image findings with T1w enhancement after contrast administration showed that regions lacking contrast enhancement also were void of PWS. Discussion This pilot study demonstrates the feasibility of utilizing ASL-MRI in paediatric patients with solid abdominal tumours and provides a basis for further research on non-invasive perfusion measurements in this study population.