To determine the diagnostic accuracy of CT for the detection of cervical lymph node metastases in patients with papillary thyroid carcinoma (PTC).

Two hundred twelve consecutive patients with surgically proven PTC were included in this study. CT images were retrospectively evaluated to determine the presence of a node metastasis using morphologic CT criteria (at least one of the following: strong nodal enhancement without hilar vessel enhancement, heterogeneous enhancement, calcification, and cystic change). The diagnostic accuracy of CT for the diagnosis of a metastatic lymph node was assessed using a level-bylevel analysis.

The accuracy of the CT finding for strong nodal enhancement was greater than the other morphologic CT criteria (81.6% and 74.5-78.5%, respectively). The sensitivity, specificity, and accuracy were 64.4%, 91.4%, and 84.3% by the morphologic CT criteria, and were 34.6%, 93.9%, and 78.2% by size criteria, respectively.

The morphologic CT criteria are more accurate than the size criteria in the detection of cervical lymph node metastases in patients with papillary thyroid carcinoma; and, strong nodal enhancement on a CT scan is the most important factor for its diagnostic accuracy.