Lymph node metastasis is one of the most important prognostic factors for patients with papillary thyroid cancer. In this study we compared the diagnostic accuracy of neck CT with that of ¹⁸F-FDG PET-CT for the preoperative evaluation of lymph node metastasis.

We reviewed the medical records of 56 patients who received surgery for papillary thyroid cancer at the Department of Surgery, Konkuk University Medical Center, from August, 2006 to January, 2009. All the patients were checked with neck CT and ¹⁸F-FDG PET-CT preoperatively for evaluating their lymph node status.

Neck CT showed a sensitivity of 40%, a specificity of 74.2%, a positive predictive value of 55.6%, a negative predictive value of 60.5% and an accuracy of 58.9%. ¹⁸F-FDG PET-CT showed a sensitivity of 48%, a specificity of 80.6%, a positive predictive value of 66.7%, a negative predictive value of 65.8% and an accuracy of 66.1%. ¹⁸FFDG PET-CT had greater sensitivity, specificity, positive predictive value, negative predictive value and accuracy than did neck CT (P=0.02) for predicting lymph node metastasis in patients with papillary thyroid cancer.

¹⁸F-FDG PET-CT can be more dependable than neck CT for preoperatively assessing lymph node metastasis in patients with papillary thyroid cancer.