Diagnostic Value of Only 18F-fluorodeocyglucose Positron Emission Tomography/Computed Tomography-Positive Lymph Nodes in Head and Neck Squamous Cell Carcinoma

Objective. The role of F-18-fluorodeocyglucose positron emission tomography (PET)/computed tomography (CT) in only PET/CT-positive lymph nodes (LNs) is not well elucidated yet. This study was conducted to evaluate the diagnostic value of only PET/CT-positive LNs without correlating positive findings on conventional imaging modalities (CT, magnetic resonance imaging [MRI], and ultrasound [US]) in patients with head and neck squamous cell carcinoma (HNSCC). Study Design. Case series with chart review. Setting. Hallym University School of Medicine. Subjects and Methods. From January 2006 to September 2009, 114 patients with HNSCC who underwent CT, MRI, US, and PET/CT before definitive surgery with neck dissection were reviewed. All imaging tests were interpreted on imaging-based nodal classification and were compared with histopathological findings. Results. Only PET/CT-positive LNs were found at 48 nodal levels in 33 patients. Thirteen of 48 (27%) nodal levels were true-positive (TP), and 35 of 48 (73%) were false-positive (FP). Fourteen nodal levels were included on N+ necks, and 34 were included on N0 necks. In N0 necks, the FP rate was significantly higher than the TP rate (28 vs 6, P=.034). Eleven only PET/CT-positive nodal levels in 10 patients were found on the contralateral neck side, and FP was significantly more prevalent than TP (8 vs 3, P=.041). No significant difference was observed for mean standardized uptake value and LN sizes between TP and FP. Conclusion. Only PET/CT-positive LNs can frequently be found and do not predict LN metastasis, because a high percentage of results were FP. Our results suggest that only PET/CT-positive LNs should be considered negative, especially in N0 and contralateral necks.