Real-time elastography for the differentiation of benign and malignant superficial lymph nodes: a meta-analysis

Real-time elastography (RTE), as a non-invasive method, is used for the classification of benign and malignant lymph nodes (LNs) and developed as an alternative to biopsy. Elasticity score (ES) and strain ratio (SR) are used for the interpretation of RTE. We studied the performance of RTE for diagnosis of malignant LNs using meta-analysis.

PubMed, the Cochrane Library, ISI Web of Knowledge, China National Knowledge Infrastructure were searched. The studies published in English or Chinese relating to the diagnostic value of RTE for superficial LNs were collected. Hierarchical summary receiver operating characteristic (HSROC) curve was used to examine the RTE accuracy. Clinical utility of RTE for LNs was evaluated by Fagan plot analysis.

A total of 9 studies which included 835 LNs were analyzed. The summary sensitivity and specificity for the diagnosis of malignant LNs were 0.74 (95% confidence interval (CI), 0.66-0.81) and 0.90 (95% CI, 0.82-0.94) for ES, and 0.88 (95% CI, 0.79-0.93) and 0.81 (95% CI, 0.49-0.95) for SR, respectively. Compared to ES, SR obviously improved the diagnostic sensitivity value. The HSROCs were 0.88 for ES and 0.91 for SR, respectively. After RTE results over the cut-off value for malignant LNs ("positive" result), the corresponding post-test probability for the presence (if pre-test probability was 50%) was 88% for ES and 82% for SR, respectively; while, in "negative" measurement, the post-test probability was 22% and 13%, respectively.

RTE has a high accuracy in the classification of superficial LNs and can potentially help to select suspicious LNs for biopsy.