Supraclavicular lymph nodes detected by 18F-FDG PET/CT in cancer patients: assessment with 18F-FDG PET/CT and sonography.

OBJECTIVE

The purposes of this study were to assess the diagnostic accuracy of 18F-FDG PET (FDG PET) for the detection of metastatic supraclavicular lymph nodes (LNs) and to propose an optimal diagnostic strategy with additional sonography, contrast-enhanced CT (CECT), or both.

MATERIALS AND METHODS

One hundred supraclavicular LNs initially detected using FDG PET were examined using sonography. Regardless of the imaging findings, all 100 supraclavicular LNs underwent sonography-guided fine-needle aspiration biopsy. The maximum standardized uptake values (SUVsmax) of the supraclavicular LNs were measured, and a receiver operating characteristic (ROC) analysis was performed to determine the cutoff SUVmax. Then we evaluated the diagnostic performance of FDG PET and figured out the optimal combination of FDG PET and sonography or CECT to improve the diagnostic accuracy of the imaging studies and minimize procedures.

RESULTS

In total, 86 of 100 PET-detected supraclavicular LNs were malignant. With application of the cutoff value obtained by ROC analysis (SUVmax=3.0), the diagnostic accuracy of FDG PET was 75.0% with a sensitivity of 74.4% and specificity of 78.6%. For supraclavicular LNs with an SUVmax of more than 3.0, FDG PET showed a positive predictive value of 95.5%; for supraclavicular LNs with an SUVmax of 3.0 or less, sonography excluded all false-negative FDG PET cases and showed a high negative predictive value of 100%. When sonography was selectively applied to cases with an SUVmax of 3.0 or less, the overall diagnostic accuracy increased to 92%.

CONCLUSION

Our study revealed a high incidence rate of metastasis in PET-detected supraclavicular LNs in cancer patients. We believe that our proposed diagnostic workflow could decrease unnecessary diagnostic procedures in the evaluation of PET-positive supraclavicular LNs in cancer patients with reliability.