Whole-body MRI versus an [18F]FDG-PET/CT-based reference standard for early response assessment and restaging of paediatric Hodgkin’s lymphoma: a prospective multicentre study

Child; Diffusion magnetic resonance imaging; Whole-body imagingNiño; Imágenes por resonancia magnética de difusión; Imágenes de cuerpo enteroNen; Imatge per ressonància magnètica de difusió; Imatge de cos sencerObjectives To compare WB-MRI with an [18F]FDG-PET/CT-based reference for early response assessment and restaging in children with Hodgkin’s lymphoma (HL). Methods Fifty-one children (ages 10–17) with HL were included in this prospective, multicentre study. All participants underwent WB-MRI and [18F]FDG-PET/CT at early response assessment. Thirteen of the 51 patients also underwent both WB-MRI and [18F]FDG-PET/CT at restaging. Two radiologists independently evaluated all WB-MR images in two separate readings: without and with DWI. The [18F]FDG-PET/CT examinations were evaluated by a nuclear medicine physician. An expert panel assessed all discrepancies between WB-MRI and [18F]FDG-PET/CT to derive the [18F]FDG-PET/CT-based reference standard. Inter-observer agreement for WB-MRI was calculated using kappa statistics. Concordance, PPV, NPV, sensitivity and specificity for a correct assessment of the response between WB-MRI and the reference standard were calculated for both nodal and extra-nodal disease presence and total response evaluation. Results Inter-observer agreement of WB-MRI including DWI between both readers was moderate (κ 0.46–0.60). For early response assessment, WB-MRI DWI agreed with the reference standard in 33/51 patients (65%, 95% CI 51–77%) versus 15/51 (29%, 95% CI 19–43%) for WB-MRI without DWI. For restaging, WB-MRI including DWI agreed with the reference standard in 9/13 patients (69%, 95% CI 42–87%) versus 5/13 patients (38%, 95% CI 18–64%) for WB-MRI without DWI. Conclusions The addition of DWI to the WB-MRI protocol in early response assessment and restaging of paediatric HL improved agreement with the [18F]FDG-PET/CT-based reference standard. However, WB-MRI remained discordant in 30% of the patients compared to standard imaging for assessing residual disease presence.This project was financially supported by the Stichting Kinderen Kankervrij (KiKa, project number 87). The data collection, analysis and interpretation of data, the writing of the paper and the decision to submit were not influenced by KiKa