The impact of lung parenchyma attenuation on nodule volumetry in lung cancer screening

Abstract

Background Recent recommendations for lung nodule management include volumetric analysis using tools that present intrinsic measurement variability, with possible impacts on clinical decisions and patient safety. This study was conducted to evaluate whether changes in the attenuation of the lung parenchyma adjacent to a nodule affect the performance of nodule segmentation using computed tomography (CT) studies and volumetric tools. Methods Two radiologists retrospectively applied two commercially available volumetric tools for the assessment of lung nodules with diameters of 5–8 mm detected by low-dose chest CT during a lung cancer screening program. The radiologists recorded the success and adequacy of nodule segmentation, nodule volume, manually and automatically (or semi-automatically) obtained long- and short-axis measurements, mean attenuation of adjacent lung parenchyma, and presence of interstitial lung abnormalities or disease, emphysema, pleural plaques, and linear atelectasis. Regression analysis was performed to identify predictors of good nodule segmentation using the volumetric tools. Interobserver and intersoftware agreement on good nodule segmentation was assessed using the intraclass correlation coefficient. Results In total, data on 1265 nodules (mean patient age, 68.3 ± 5.1 years; 70.2% male) were included in the study. In the regression model, attenuation of the adjacent lung parenchyma was highly significant (odds ratio 0.987, p < 0.001), with a large effect size. Interobserver and intersoftware agreement on good segmentation was good, although one software package performed better and measurements differed consistently between software packages. Conclusion For lung nodules with diameters of 5–8 mm, the likelihood of good segmentation declines with increasing attenuation of the adjacent parenchyma.

Quantum Iterative Reconstruction for Low-Dose Ultra-High-Resolution Photon-Counting Detector CT of the Lung

“…Moreover, our results indicate that mean CT attenuation was comparable among reconstructions with clinically negligible (though statistically significant) absolute differences of a maximum of 4 HU between two reconstructions. Such stability is important for example, in automated lung emphysema imaging or nodule volumetry [ 41 ] in which attenuation thresholds are being used to distinguish healthy from affected lung parenchyma.…”

Factors influencing the outcome of volumetry tools for pulmonary nodule analysis: a systematic review and attempted meta-analysis

“…In two phantom studies by Gavrielides et al, the difference in attenuation between a synthetic nodule and the background was statistically significant [ 39 , 67 ]. Recently, Penha et al reported that the quality of pulmonary nodule segmentation by volumetry tools decreases with increasing attenuation of the surrounding parenchyma [ 114 ].…”

Contextualizing the Role of Volumetric Analysis in Pulmonary Nodule Assessment: AJR Expert Panel Narrative Review

“…This approach is currently the most widely applied method in clinical practice. The process generally requires third-party software that can either be launched from or is available within the PACS [14] (Fig. 1).…”

“…The proportion of solid nodules not considered reliably segmented by volumetry is approximately 7-26%, depending on the software package [60]. Using two packages, including one embedded within a commercial PACS, Penha et al [14] found that the pro-portions of improperly segmented nodules for two readers was 11.6% and 11.9% for one tool and 14.2% and 15.2% for the other.…”