Preoperative staging of papillary thyroid carcinoma : comparison of ultrasonography and computed tomography

Abstract

[한글]

[영문]

Objective. To compare the diagnostic accuracies of ultrasonography (US) and computed tomography (CT) for preoperative evaluation of primary tumors and cervical lymph nodes in patients with papillary thyroid carcinoma (PTC), and to determine whether CT provides additional diagnostic value compared to US alone in these patients.Materials and Methods. The study population consisted of 299 consecutive patients with pathologically proven PTC. We assessed the diagnostic accuracies of US, CT, and combined US and CT [US/CT] for the evaluation of primary tumors and lymph node metastasis. We performed subgroup analysis to compare papillary thyroid microcarcinomas (PTMC, 10 mm or less in maximum diameter) with PTC greater than 1 cm in maximum diameter.Results. US predicted extrathyroidal tumor extension and bilateral thyroid lobe malignancy more accurately than CT (p<0.05) for overall lesions as well as for the 2 subgroups. For predicting central node (Ⅵ) metastasis, CT showed higher sensitivity than US alone (p=0.040) for overall lesions. Although US/CT showed higher sensitivity compared to US alone in predicting central node metastases for the 2 subgroups, US/CT did not reach statistical significance in sensitivity for PTMC. US alone and US/CT showed higher sensitivity than CT in predicting lateral node (levels Ⅱ to Ⅴ) metastasis, however, there was no significant difference in diagnostic values between US and US/CT for overall lesions or for the 2 subgroups (p>0.05).Conclusions. High-resolution US can provide an accurate preoperative evaluation of extrathyroidal tumor extension and lateral lymph node metastasis. CT showed higher sensitivity than US alone in detecting central lymph node metastasis for overall lesions. For PTMC, however, there was no significant difference in diagnostic accuracy between US, CT, and US/CT.