Potential performance of dual-time-point 18F-FDG PET/CT compared with single-time-point imaging for differential diagnosis of metastatic lymph nodes: a meta-analysis

In recent years, dual-time-point (DTP) fluorine-18 fluorodeoxyglucose PET/computed tomography (CT) has emerged as a new method for evaluating metastatic lymph nodes in cancer patients. We performed this meta-analysis to evaluate the performance of DTP PET/CT compared with single-time-point (STP) imaging for differential diagnosis of lymph nodes metastases. On the basis of data from included studies, pooled sensitivity, specificity, diagnostic odds ratio, positive likelihood ratio, and negative likelihood ratio were calculated. Summary receiver-operating characteristic curves were also constructed to assess the diagnostic value of DTP PET/CT and STP imaging in detecting metastatic lymph nodes. Totally, 17 articles were included in the analysis. On a per-patient basis, the pooled sensitivity and specificity were 0.74 [95% confidence interval (CI): 0.68-0.79] and 0.77 (95% CI: 0.72-0.81) for DTP PET/CT and 0.68 (95% CI: 0.61-0.73) and 0.81 (95% CI: 0.78-0.85) for STP PET/CT, respectively. On a per-lesion basis, the pooled sensitivity of DTP and STP PET/CT was 0.82 (95% CI: 0.79-0.84) and 0.80 (95% CI: 0.78-0.83), respectively. The pooled specificity was 0.88 (95% CI: 0.86-0.89) for DTP PET/CT and 0.82 (95% CI: 0.80-0.84) for STP PET/CT. Compared with STP imaging, DTP PET/CT has higher sensitivity but lower specificity in detecting lymph nodes metastases on a per-patient analysis, and DTP PET/CT performs only a little better than STP PET/CT on a per-lesion basis. The current results of our meta-analysis do not support the routine use of DTP imaging for the diagnosis of metastatic lymph nodes. Further prospective research with large samples is required to better define the potential benefits of DTP PET/CT imaging.