Diagnostic Performance of Dual-time 18F-FDG PET in the Diagnosis of Pulmonary Nodules: A Meta-analysis

Perform a comprehensive meta-analysis evaluating the diagnostic performance of dual time point deoxy-2-[ 18F]fluoro-D-glucose positron emission tomography (FDG-PET) in the diagnosis of pulmonary nodules. MEDLINE, EMBASE, and PUBMED were queried between January 2000 and January 2011. Studies were included if they: 1) used dual time point FDG-PET as a diagnostic test for pulmonary nodules, 2) used pathology or clinical follow-up as the reference standard, and 3) reported absolute number of true-positive (TP), true-negative (TN), false-positive (FP), and false-negative (FN) results or stated sufficient data to derive these values. Summary sensitivity (SN), summary specificity (SP), positive and negative likelihood ratios (LR+) and (LR−), and diagnostic odds ratio were calculated. Heterogeneity of the results was assessed using Forest plots and the value of inconsistency index (I 2). Inclusion criteria were fulfilled by 10 articles with a total of 816 patients and 890 pulmonary nodules. The summary sensitivity was 85% (82%–89% at 95% confidence interval [CI]) and summary specificity was 77% (CI: 72%–81%), with a LR+ of 2.7 (CI: 1.4–5.2) and a LR− of 0.26 (CI: 0.14–0.49). Diagnostic odds ratio was 11 (CI: 3.8–32.2). Significant heterogeneity was found in the sensitivity (I 2 = 77%) and specificity (90.3%). Dual time point FDG-PET demonstrates similar sensitivity and specificity to single time point FDG-PET in the diagnosis of pulmonary nodules. The additive value of the dual time point FDG-PET is questionable, primarily because of the significant overlap of benign and malignant nodule FDG-PET characteristics and lack of consensus criteria for quantitative thresholds to define nodules as malignant.