The value of 18F-FDG-PET/CT in the diagnosis of solitary pulmonary nodules: A meta-analysis

Abstract

Background: Solitary pulmonary nodules (SPNs) are common imaging findings. Many studies have indicated that F-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG-PET/CT) is an accurate test for distinguishing benign and malignant SPNs. The aim of this study was to investigate the value of F-FDG-PET/CT in the diagnosis of malignant SPNs.

Methods: We systematically searched the PubMed and Embase databases up to March 2017, and published data on sensitivity, specificity, and other measures of diagnostic accuracy of F-FDG-PET/CT in the diagnosis of malignant SPNs were meta-analyzed. Statistical analyses were undertaken using Meta-DiSc 1.4 software and Stata version 12.0. The measures of accuracy of F-FDG-PET/CT in the diagnosis of malignant SPNs were pooled using random-effects models.

Results: A total of 20 publications reporting 21 studies were identified. Pooled results indicated that F-FDG-PET/CT showed a diagnostic sensitivity of 0.89 (95% confidence interval [CI], 0.87-0.91) and a specificity of 0.70 (95% CI, 0.66-0.73). The positive likelihood ratio was 3.33 (95% CI, 2.35-4.71) and the negative likelihood ratio was 0.18 (95% CI, 0.13-0.25). The diagnostic odds ratio was 22.43 (95% CI, 12.55-40.07).

Conclusions: F-FDG-PET/CT showed insufficient sensitivity and specificity for diagnosing malignant SPNs; it cannot replace the "gold standard" pathology by resection or percutaneous biopsy. Larger studies are required for further evaluation.

Figure 1

Forest plot of estimates of sensitivity for ¹⁸F-FDG-PET/CT in the diagnosis of malignant SPNs. Point estimates of sensitivity from each study are shown as solid circles, the size of which reflects the total number of cases and controls. Error bars show 95% confidence intervals. Numbers indicate the reference numbers of the studies.

Figure 2

Forest plot of estimates of specificity for ¹⁸F-FDG-PET/CT in the diagnosis of malignant SPNs. Point estimates of specificity from each study are shown as solid circles, the size of which reflects the total number of cases and controls. Error bars show 95% confidence intervals. Numbers indicate the reference numbers of the studies.

Figure 3

Forest plot of estimates of positive likelihood ratios for ¹⁸F-FDG-PET/CT in the diagnosis of malignant SPNs. Point estimates of the positive likelihood ratios from each study are shown as solid circles, the size of which reflects the total number of cases and controls. Error bars show 95% confidence intervals. Numbers indicate the reference numbers of studies.

Figure 4

Forest plot of estimates of the negative likelihood ratios for ¹⁸F-FDG-PET/CT in the diagnosis of malignant SPNs. Point estimates of negative likelihood ratios from each study are shown as solid circles, the size of which reflects the total number of cases and controls. Error bars show 95% confidence intervals. Numbers indicate the reference numbers of the studies.

Figure 5

Forest plot of estimates of diagnostic odds ratios for ¹⁸F-FDG-PET/CT in the diagnosis of malignant SPNs. Point estimates of diagnostic odds ratios from each study are shown as solid circles, the size of which reflects the total number of cases and controls. Error bars show 95% confidence intervals. Numbers indicate the reference numbers of the studies.

Figure 6

Summary receiver operating characteristic curves for ¹⁸F-FDG-PET/CT. Each study is depicted as a solid circle, the size of which reflects the total number of cases and controls.

Figure 7

Funnel plot for evaluating publication bias among the 18 studies included in the meta-analysis. The log of the DOR is plotted against the standard error of the log DOR; the latter serves as an indicator of the sample size. Each article is shown as a solid circle, and the regression line is shown.