Evaluation of cervical lymph node metastasis in thyroid cancer patients using real-time CT-navigated ultrasonography: preliminary study

PURPOSE: To evaluate the diagnostic accuracy of real-time neck computed tomography (CT)-guided ultrasonography (US) in detecting cervical neck lymph node metastasis (LNM) in patients with papillary thyroid cancer (PTC). METHODS: We retrospectively reviewed data from 176 patients (mean age, 43 years; range, 23 to 74 years) with surgically confirmed PTC who underwent preoperative US, neck CT, and neck CTguided US. We then compared the sensitivities and diagnostic accuracies of each of the three above modalities in detecting cervical LNM. RESULTS: Preoperative US showed 17.3% sensitivity and 58.5% diagnostic accuracy in detecting central LNM compared with 64.3% sensitivity and 89.2% diagnostic accuracy in detecting lateral neck LNM. Neck CT showed 23.5% sensitivity and 55.7% diagnostic accuracy in detecting central LNM and 71.4% sensitivity with 90.9% diagnostic accuracy in detecting lateral neck LNM. CT-guided US exhibited 37.0% sensitivity and 63.1% diagnostic accuracy in detecting central LNM compared with 92.9% sensitivity and 96.0% diagnostic accuracy in detecting lateral LNM. CT-guided US showed higher diagnostic accuracy with superior sensitivity in detecting central and lateral LNM than did US (P<0.001, P=0.011) and CT (P=0.026, P=0.063). CONCLUSION: Neck CT-guided US is a more accurate technique with higher sensitivity for detecting cervical LNM than either US or CT alone. Therefore, our data indicate that neck CT-guided US is an especially useful technique in preoperative examinations.