Objective To evaluate the clinical value of magnetic resonance imaging (MRI) in the diagnosis of pelvic lateral lymph node metastasis in rectal cancer.

Methods EMbase, PubMed, The Cochrane Library, CNKI and WanFang Data databases were searched up to March 2019 to collect relevant studies about MRI diagnosis of pelvic lateral lymph nodes in rectal cancer. Two researchers independently screened the literature, extracted the data and assessed the risk of bias, used the Stata 15 software for statistical analysis and calculated the combined sensitivity (SEN pooled), specificity (SPE pooled) and diagnostic odds ratio (DOR). A summary receiver operating characteristic (SROC) curve was plotted and the area under the curve (AUC) was calculated.

Results A total of 11 studies involving 1059 patients were included. The pooled Sen, Spe, +LR, -LR and DOR were 0.77 (95% CI:0.38-0.88), 0.77 (95% CI:0.69-0.83), 3.3 (95% CI:2.4-4.5), 0.3 (95% CI:0.23-0.41) and 11 (95% CI:6-18), respectively. The AUC of SROC was 0.83(95% CI:0.80-0.86).

Conclusion Taken the short diameter of lymph nodes as the diagnostic criteria, the sensitivity and specificity of MRI in the diagnosis of lateral lymph node metastasis of rectal cancer are moderate; but in the absence of better imaging screening, MRI is still the recommended means.