The Role of Whole-Body MRI with Diffusion Sequence versus FDG-PET/CT: A Comparative Study in Pediatric Patients with Hodgkin Lymphoma from Diagnosis to End of Treatment

Abstract Background In pediatric oncology, minimizing exposure to ionizing radiation is crucial due to the potential long-term risks, including the development of secondary malignancies. For pediatric patients with Hodgkin lymphoma, identifying radiation-free imaging methods that can reliably replace conventional techniques is a clinical priority. Objective To evaluate the correlation between whole-body magnetic resonance imaging with diffusion-weighted imaging (WB-MRI/DWI) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) findings in pediatric patients with Hodgkin lymphoma, and to determine whether WB-MRI/DWI can serve as a viable alternative in staging and follow-up protocols. Materials and Methods This single-center retrospective study included pediatric patients aged 6.6–17.0 years (mean ± SD: 14.9 ± 3.2 years) with histopathologically confirmed Hodgkin lymphoma who underwent both WB-MRI/DWI and FDG-PET/CT within a maximum interval of 21 days. Imaging was performed with an average interval of 7.6 ± 4.9 days. Two radiologists independently evaluated all studies, recording the number of involved sites and the largest lymph node cluster diameter. Pearson correlation coefficients and Kappa agreement analyses were performed, using FDG-PET/CT as the reference standard. Results Among 33 patients (21 male [63.6%], 12 females [36.4%]), 150 sites were positive on FDG-PET/CT and 198 on WB-MRI/DWI. There was a strong correlation between WB-MRI/DWI and FDG-PET/CT for both the number of positive sites (r = 0.831, p < 0.001) and largest lymph node diameters (r = 0.863, p < 0.001). WB-MRI/DWI demonstrated 96% sensitivity, 95% specificity, an overall agreement of 95.2%, and a Kappa index of 0.8004 (p < 0.001). Conclusion WB-MRI/DWI shows excellent agreement with FDG-PET/CT for the evaluation of Hodgkin lymphoma in pediatric patients and may represent a safe, effective, and radiation-free alternative for staging and follow-up in this population.