18 F-FDG PET/MRI for Staging and Interim Response Assessment in Pediatric and Adolescent Hodgkin Lymphoma: A Prospective Study with 18 F-FDG PET/CT as the Reference Standard.

Treatment regimens for pediatric Hodgkin lymphoma (HL) depend on accurate staging and treatment response assessment, based on accurate disease distribution and metabolic activity depiction. With the aim of radiation dose reduction, we compared the diagnostic performance of ¹⁸ F-FDG PET/MRI with a ¹⁸ F-FDG PET/CT reference standard for staging and response assessment. Methods: Twenty-four patients (mean age, 15.4 y; range, 8-19.5 y) with histologically proven HL were prospectively and consecutively recruited in 2015 and 2016, undergoing both ¹⁸ F-FDG PET/CT and ¹⁸ F-FDG PET/MRI at initial staging ( n = 24) and at response assessment ( n = 21). The diagnostic accuracy of ¹⁸ F-FDG PET/MRI for both nodal and extranodal disease was compared with that of ¹⁸ F-FDG PET/CT, which was considered the reference standard. Discrepancies were retrospectively classified as perceptual or technical errors, and ¹⁸ F-FDG PET/MRI and ¹⁸ F-FDG PET/CT were corrected by removing perceptual error. Agreement with Ann Arbor staging and Deauville grading was also assessed. Results: For nodal and extranodal sites combined, corrected staging ¹⁸ F-FDG PET/MRI sensitivity was 100% (95% CI, 96.7%-100%) and specificity was 99.5% (95% CI, 98.3%-99.9%). Corrected response-assessment ¹⁸ F-FDG PET/MRI sensitivity was 83.3% (95% CI, 36.5%-99.1%) and specificity was 100% (95% CI, 99.2%-100%). Modified Ann Arbor staging agreement between ¹⁸ F-FDG PET/CT and ¹⁸ F-FDG PET/MRI was perfect (κ = 1.0, P = 0.000). Deauville grading agreement between ¹⁸ F-FDG PET/MRI and ¹⁸ F-FDG PET/CT was excellent (κ = 0.835, P = 0.000). Conclusion: ¹⁸ F-FDG PET/MRI is a promising alternative to ¹⁸ F-FDG PET/CT for staging and response assessment in children with HL.
(© 2021 by the Society of Nuclear Medicine and Molecular Imaging.)