Comprehensive imaging of residual/recurrent nasopharyngeal carcinoma using whole-body MRI at 3 T compared with FDG-PET-CT

Objective: To prospectively compare the diagnostic potential of 3-T wholebody magnetic resonance imaging (WB-MRI) and integrated fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) (FDG-PET-CT), and their combined interpretation for the detection of residual/recurrent nasopharyngeal carcinoma (NPC). Methods: We enrolled 179 NPC patients at high risk of residual disease or with suspected recurrence. WB-MRI and FDG-PET-CT were obtained with an interval of <10days. Results: Fifty-five (30.7%) patients were found to have residual/recurrent tumours. In a patient-based analysis, the sensitivity, specificity and diagnostic capability of WB-MRI were similar to those of FDG-PET-CT (90.9% vs. 87.3%, P=0.69; 91.1% vs. 90.3%, P>0.99; 0.929 vs. 0.924, P= 0.83, respectively). Combined interpretation of WB-MRI with FDG-PET-CT increased the sensitivity to 94.5%. A slight improvement in the diagnostic capability was obtained using a combined interpretation of WB-MRI and FDG-PET-CT over WB-MRI alone (0.952 vs. 0.929, P= 0.22) and FDG-PET-CT alone (0.952 vs. 0.924, P=0.11). Conclusions: Three-Tesla WB-MRI achieved a similar diagnostic capability to FDG-PET-CT for the detection of residual/recurrent NPC. Both techniques have different advantages, and their combined interpretation can yield a slightly higher diagnostic capability. In clinical practice, 3-T WB-MRI can offer an accurate and comprehensive assessment of residual/recurrent NPC.