Prospective comparative study of MRI including diffusion-weighted images versus FDG PET-CT for the detection of recurrent head and neck squamous cell carcinomas after (chemo)radiotherapy

Objective: This prospective study aims to test if MRI including diffusion weighted images can replace FDG PET-CT in the diagnosis of patients with suspicion of local recurrent head and neck squamous cell carcinomas after (chemo)radiation. Methods: Seventy-five patients suspected of local recurrence underwent a MRI and a FDG PET-CT. Qualitative assessment of the images was performed. Reference standard was the results of biopsy or the absence of a recurrence during follow up. Results: Seventy patients were included. Fifty percent had local recurrence. FDG PET-CT had accuracy of 71% compared to 73% for MRI. The sensitivity and specificity were 97% compared to 69% and 46% compared to 77% for FDG PET-CT and MRI respectively. Conclusions: MRI showed similar diagnostic accuracy, superior specificity but inferior sensitivity compared to FDG PET-CT. Based on current results, we consider MRI including diffusion weighted sequences unable to replace FDG PET-CT as a single imaging modality when local recurrent disease of HNSCC after (C)RT is suspected.