Diagnostic performance of ultrasound and computed tomography in parallel for the diagnosis of lymph node metastasis in patients with thyroid cancer: a systematic review and meta-analysis

Background: Currently, there is no evidence-based medical evidence for the diagnosis of lymph node metastasis (LNM) of thyroid cancer (TC) by ultrasound combined with computed tomography (US + CT), and the results of various studies on its diagnostic efficacy are inconsistent. Therefore, the diagnosis of cervical LNM by US + CT is controversial at present. The aims of the present systematic review and metaanalysis were to evaluate the diagnostic performance of US + CT in parallel for diagnosing cervical LNM in patients with TC. Methods: We searched PubMed, EMBASE, Cochrane Library, Web of Science, and Wanfang Medical Network (Core journals only) for studies prior to May 2022 on the performance of US and CT in parallel for diagnosing cervical lymph nodes. The studies were screened according to inclusion and exclusion requirements, and the methodologic quality of the included studies was independently assessed by 2 reviewers using tailored questionnaires and criteria provided by Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). We calculated the sensitivity, specificity, and diagnostic odds ratio (DOR) of cervical LNM for the central region, lateral neck, and whole neck. Meta-regression was performed to determine which parameters caused high diagnostic heterogeneity. Results: We included 11 studies of 6,261 patients with TC and 8,394 non-TC patients were included in the study. Most of the risk assessments included in the study were low risk, with no high-risk items. For the parallel test of US + CT, pooled sensitivity and specificity in the central region and lateral neck were 0.73 [95% confidence interval (CI): 0.56-0.85] and 0.80 (95% CI: 0.72-0.85), respectively. The calculated positive likelihood ratio was 3.6 (95% CI: 2.9-4.4), negative likelihood ratio was 0.34 (95% CI: 0.20-0.56), and DOR was 11 (95% CI: 6-18). The area under the curve was 0.83. For US + CT, the pooled sensitivity and specificity in the central region and lateral neck were 0.73 (95% CI: 0.56-0.85) and 0.80 (95% CI: 0.72-0.85), respectively. Discussion: The diagnostic efficiency of CT for lateral cervical LNM is greater than for central cervical LNM. CT has high sensitivity and accuracy for the diagnosis of central cervical LNMs. US + CT is important for the preoperative examination of cervical LNMs in TC.