The Clinical Usefulness of 18F-FDG PET/CT for the Evaluation of Lymph Node Metastasis in Periorbital Malignancies

ABSTRACT

OBJECTIVE: The aim of this study was to assess the clinical role of 18F-FDG PET/CT for the evaluation of lymph node metastasis in periorbital malignancies, compared with CT alone. MATERIALS AND METHODS: We analyzed eighteen PET/CT and CT scans in 15 patients with biopsy-proven periorbital malignancies. We compared the diagnostic capabilities of PET/CT and CT with regard to nodal metastasis by level-by-level analysis and by N staging prediction. The reference standards were surgical pathology (n = 7) from dissected lymph node specimens and the results from radiological follow-up (n = 11, mean 20.5 months; range 10-52 months). Moreover, any changes in patient care as prompted by PET/CT were recorded and compared with treatment planning for CT alone. RESULTS: PET/CT had a sensitivity of 100%, while CT had a sensitivity of 57% (p = 0.03) for nodal metastasis by level-by-level analysis. PET/CT had a specificity of 97%, positive predictive value of 93%, negative predictive value of 100%, and diagnostic accuracy of 98%, while the CT values for these same parameters were 97%, 89%, 82%, and 84%, respectively. PET/CT correctly predicted N staging with an accuracy of 100%, while CT was only 83% accurate (p = 0.01). Regarding the impact on patient care, the extent of surgery for regional lymph nodes and the treatment decision were modified by PET/CT in 39% of patients. CONCLUSION: PET/CT could provide useful information in the management of regional lymph node metastases in patients with periorbital malignancies.