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

Danyang Wang,1 Yanlei Huo,1 Suyun Chen,1 Hui Wang,1 Yingli Ding,2 Xiaochun Zhu,3 Chao Ma1,4 1Department of Nuclear Medicine, Affiliated XinHua Hospital of Shanghai Jiaotong University School of Medicine, Shanghai, China; 2Department of Nuclear Medicine, Affiliated Third People’s Hospital of Shanghai Jiaotong University School of Medicine, Shanghai, China; 3Department of Nuclear Medicine, Affiliated Ninth People’s Hospital of Shanghai Jiaotong University School of Medicine, Shanghai, China; 4Department of Nuclear Medicine, Tenth People’s Hospital of Tongji University, Shanghai, China Purpose: 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is the reference standard in staging of 18F-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 18F-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 18F-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 18F-FDG PET/CT for initial staging and for assessing possible heterogeneity (χ2) 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 18F-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 18F-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 18F-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 18F-FDG PET/CT for staging of 18FDG-avid lymphomas, where 18F-FDG PET/CT remains the standard of care. Additionally, WB-MRI seems a less histology-dependent functional imaging test than 18F-FDG PET/CT and may be the imaging test of choice for staging of indolent NHLs with low 18F-FDG avidity. Keywords: lymphoma, meta-analysis, whole-body diffusion-weighted MRI, 18F-FDG PET/CT, stagin