Whole-body MRI versus (18)F-FDG PET/CT for pretherapeutic assessment and staging of lymphoma: a meta-analysis

PURPOSE: (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) is the reference standard in staging of (18)F-FDG-avid lymphomas; however, there is no recommended functional imaging modality for indolent lymphomas. Therefore, we aimed to compare the performance of whole-body magnetic resonance imaging (WB-MRI) with that of (18)F-FDG PET/CT for lesion detection and initial staging in patients with aggressive or indolent lymphoma. MATERIALS AND METHODS: We searched the MEDLINE, EMBASE, and CENTRAL databases for studies that compared WB-MRI with (18)F-FDG PET/CT for lymphoma staging or lesion detection. The methodological quality of the studies was assessed using version 2 of the “Quality Assessment of Diagnostic Accuracy Studies” tool. The pooled staging accuracy (μ) of WB-MRI and (18)F-FDG PET/CT for initial staging and for assessing possible heterogeneity (χ(2)) across studies were calculated using commercially available software. RESULTS: Eight studies comprising 338 patients were included. In terms of staging, the meta-analytic staging accuracies of WB-MRI and (18)F-FDG PET/CT for Hodgkin lymphoma and aggressive non-Hodgkin lymphoma (NHL) were 98% (95% CI, 94%–100%) and 98% (95% CI, 94%–100%), respectively. The pooled staging accuracy of (18)F-FDG PET/CT dropped to 87% (95% CI, 72%–97%) for staging in patients with indolent lymphoma, whereas that of WB-MRI remained 96% (95% CI, 91%–100%). Subgroup analysis indicated an even lower staging accuracy of (18)F-FDG PET/CT for staging of less FDG-avid indolent NHLs (60%; 95% CI, 23%–92%), in contrast to the superior performance of WB-MRI (98%; 95% CI, 88%–100%). CONCLUSION: WB-MRI is a promising radiation-free imaging technique that may serve as a viable alternative to (18)F-FDG PET/CT for staging of (18)FDG-avid lymphomas, where (18)F-FDG PET/CT remains the standard of care. Additionally, WB-MRI seems a less histology-dependent functional imaging test than (18)F-FDG PET/CT and may be the imaging test of choice for staging of indolent NHLs with low (18)F-FDG avidity.