ABSTRACT
To evaluate an optimized F-18-flurodeoxyglucose-positron emission tomography/computed tomography [FDG-PET/CT] acquisition protocol for head and neck cancer and assess the usefulness of combined FDG-PET/CT in locating unknown primary tumors in patients with biopsy-proven cervical lymph node metastases. Subjects and Twenty-one patients with cervical lymph node metastases of unknown primary tumors underwent staging with FDG-PET/CT. The images of FDG-PET alone, CT alone, FDG-PET/CT read side by side and fused and FDG-PET/CT were evaluated separately by 2 physicians. Imaging results were correlated with either histology [n = 14] or clinical follow-up [n = 7]. On the fused FDG-PET/CT images, primary tumors were identified in 12 patients [57%]; with FDG-PET alone and FDG-PET and CT read side by side 11 [52%] primary tumors were found while CT alone identified 5 [23%] primary tumors. Our data indicate that fused FDG-PET and CT images increased the sensitivity of detecting carcinoma of unknown primary [CUP] tumors compared to CT alone, but not to FDG-PET alone or FDG-PET and CT read side by side. Hence accurate fusion of functional and morphologic data by FDG-PET/CT is a promising imaging modality in the clinical workup of patients with cervical CUP tumors