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 CT-guided 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.