Interreader Agreement of Lung-RADS: A Systematic Review and Meta-Analysis.

Abstract

<b>BACKGROUND</b>. Lung-RADS has shown variable interreader agreement in the literature, in part related to a broad range of factors that may influence the consistency of its implementation. <b>OBJECTIVE</b>. The purpose of this study was to assess the interreader agreement of Lung-RADS and to investigate factors influencing the system's variability. <b>EVIDENCE ACQUISITION</b>. The Embase, PubMed, and Cochrane databases were searched for original research studies published through June 18, 2024, that reported the interreader agreement of Lung-RADS on chest CT. Random-effects models were used to calculate pooled kappa coefficients for Lung-RADS categorization and pooled intraclass correlation coefficients (ICCs) for nodule size measurements. Potential sources of heterogeneity were explored using metaregression analyses. <b>EVIDENCE SYNTHESIS</b>. The analysis included 11 studies (1470 patients) for Lung-RADS categorization and five studies (617 patients) for nodule size measurement. Interreader agreement for Lung-RADS categorization was substantial (κ = 0.72 [95% CI, 0.57-0.82]), and that for nodule size measurement was almost perfect (ICC = 0.97 [95% CI, 0.90-0.99]). Interreader agreement for Lung-RADS categorization was significantly associated with the method of nodule measurement (<i>p</i> = .005), with pooled kappa coefficients of 0.95, 0.91, and 0.66 for studies using computer-aided detection (CAD)-based semiautomated volume measurements, CAD-based semiautomated diameter measurements, and manual diameter measurements, respectively. Interreader agreement for Lung-RADS categorization was also significantly associated with studies' nodule type distribution (<i>p</i> < .001), with pooled kappa coefficients of 0.85, 0.76, and 0.55 for studies evaluating 100% solid nodules, 30-99% solid nodules, and fewer than 30% solid nodules, respectively. Interreader agreement for nodule size measurement was significantly associated with radiation dose (<i>p</i> < .001), with pooled ICCs of 0.97, 0.96, and 0.59 for studies that used standard-dose CT, low-dose CT, and ultralow-dose CT, respectively. Interreader agreement for nodule size measurement was also significantly associated with the Lung-RADS version that was used (<i>p</i> = .02), with pooled ICCs of 0.99 and 0.93 for studies using Lung-RADS 1.1 and Lung-RADS 1.0, respectively. <b>CONCLUSION</b>. Although they support the overall reliability of Lung-RADS, the findings indicate roles for CAD assistance as well as training and standardized approaches for nodule type characterization to further promote reproducible application. <b>CLINICAL IMPACT</b>. Consistent nodule assessments will be critical for Lung-RADS to optimally impact patient management and outcomes.