Interobserver Variability in Chest CT and Whole Body FDG-PET Screening for Distant Metastases in Head and Neck Cancer Patients

PURPOSE: The aim of the study was to assess the interobserver variability in chest computed tomography (CT) and whole body 2-deoxy-2-[(18)F]fluoro-d-glucose positron emission tomography (FDG-PET) screening for distant metastases in head and neck squamous cell carcinoma (HNSCC) patients. PROCEDURE: Chest CT and whole body FDG-PET of 69 HNSCC patients with high-risk factors who underwent screening for distant metastases were analyzed. All scans were independently read by two experienced radiologists or nuclear physicians who were blinded to the other examinations and follow-up results. RESULTS: A kappa of 0.516 was found for assessment of size on CT. Kappa values for origin and susceptibility of 0.406 and 0.512 for CT and 0.834 and 0.939 for PET were found, respectively. The overall conclusions had a kappa of 0.517–0.634 for CT and 0.820–1.000 for PET. CONCLUSIONS: In screening for distant metastases in HNSCC patients with high-risk factors, chest CT readings had a reasonable to substantial agreement, while PET readings showed an almost perfect agreement. These findings suggest that for optimal assessment in clinical practice, PET most often can be scored by one observer, but CT should probably more often be scored by different observers in consensus or combined with PET.