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

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.