Diagnostic Performance of CT in Detection of Metastatic Cervical Lymph Nodes in Patients with Thyroid Cancer: a Systematic Review and Meta-analysis

Objectives: Although ultrasound (US) is a standard modality for the assessment of cervical lymph node metastasis in patients with thyroid cancer, there is an increasing trend in the number of articles describing the use of contrast-enhanced computed tomography (CT). The purpose of this systematic review and meta-analysis was to evaluate the diagnostic performance of CT in the diagnosis of metastatic cervical lymph nodes and to identify the parameters responsible for heterogeneity in diagnostic performance.

Methods: Ovid-MEDLINE and EMBASE databases were searched up to May 22, 2018, for studies on the diagnostic performance of CT. The pooled sensitivity and specificity of all studies were calculated. In addition, subgroup analysis and meta-regression analysis were performed to evaluate factors responsible for heterogeneity.

Results: Seventeen (6378 patients, 11,590 lymph nodes) studies were included. The pooled sensitivity was 55% (95% CI, 47-63%), and the pooled specificity was 87% (95% CI, 90-95%). Higgins I statistic demonstrated substantial heterogeneity in the sensitivity (I = 96.3%) and specificity (I = 93.8%). In a per-neck level subgroup analysis, the Higgins I statistic demonstrated reduced heterogeneity in both sensitivity and specificity. In the meta-regression analysis, variation in the CT protocols, such as contrast amount, scan phase, and reconstruction slice thickness, was a statistically significant factor causing heterogeneity.

Conclusions: CT demonstrated acceptable diagnostic performance in the pre- and postoperative diagnosis of metastatic cervical lymph nodes in patients with thyroid cancer. Variation in the CT protocols was a main factor causing heterogeneity among the included studies.

Key Points: • The role of contrast-enhanced computed tomography (CT) needs to be reassessed. • CT demonstrated acceptable diagnostic performance in the diagnosis of metastatic cervical lymph nodes in patients with thyroid cancer in the meta-analysis. • Variation in the CT protocols was a main factor causing heterogeneity in the meta-regression analysis.