Diagnosis of Cervical Metastatic Lymph Nodes in Papillary Thyroid Carcinoma: Is CT Enhancement Useful for Diagnosing Lymph Node Metastasis?

Shin, Hyun Joo; Kim, Eun Kyung; Moon, Hee Jung; Kwak, Jin Young

Abstract

PURPOSE
We wanted to determine the utility of CT enhancement for diagnosing metastatic lymphadenopathy in patients with papillary thyroid carcinoma (PTC), and especially in the lymph nodes (LNs) of the lateral neck level and that are not suspicious for metastasis on ultrasonography (US).
MATERIALS AND METHODS
Our study population included 34 consecutive LNs of 31 patients (25 females and 6 males, mean age: 46.7 yrs) with PTC and who had no suspicious metastatic lateral cervical LN on preoperative US, but enhancement of the lateral cervical LNs was seen on CT. To objectify the degree of enhancement, the difference of Hounsfield units between the suspicious LN and that of the ipsilateral SCM muscle was calculated. For the node-by-node analysis, marking of the corresponding LN with CT enhancement on the second look US was performed. The final assessment was attained by surgical dissection of the marked LNs. The medical records were reviewed for the patients' age and gender and the size of the LNs.
RESULTS
Among the 34 LNs, 17 LNs were diagnosed as metastasis and 17 were benign. There was no difference in the size of the LNs between two the groups (benign and metastatic). The patients who had metastatic LNs were younger than those patients with benign LNs (p = 0.037). The incidence of metastatic LN was higher in the male patients than in the female patients (F:M = 38.5%:100%, p = 0.018). There was no statistical difference between the metastatic LNs and benign LNs according to the degree of enhancement (p = 0.953).
CONCLUSION
The degree of CT enhancement is not feasible to use for diagnosing metastatic LNs in the lateral neck level in patients with PTC.