Reproducibility of the CT radiomic features of pulmonary nodules: the effects of the CT reconstruction algorithm, radiation dose, and contrast agent.

Abstract

Background: The reproducibility of radiomic features (RFs) is essential in lung nodule diagnosis. This study aimed to prospectively investigate the effects of computed tomography (CT) scanning parameters on the reproducibility of RFs in pulmonary nodules.

Methods: Patients with pulmonary nodules who underwent chest CT scans at the Cancer Hospital of the Chinese Academy of Medical Sciences between July 2018 and March 2019 were prospectively included in the study. Six sequences with three pairs of different scanning parameters, including the reconstruction algorithm [filtered back projection (FBP) vs. 50% adaptive statistical iterative reconstruction-V (ASiR-V)], radiation dose (low dose vs. standard dose), and contrast agent [contrast-enhanced (CE) CT vs. non-contrast enhanced (NE) CT], were used for each patient. When one of the scanning parameters was changed, the other two remained fixed. The nodules were classified into pure ground-glass nodules (pGGNs), part-solid nodules (PSNs), and solid nodules (SNs) according to the nodule consistency. RFs with an intraclass correlation coefficient (ICC) >0.75 were considered to have good retest reliability. All the RF values of the different scanning parameters and nodule consistency were investigated and compared.

Results: A total of 150 pulmonary nodules, including 50 pGGNs, 50 PSNs, and 50 SNs, in 96 patients (mean age: 52±10 years; 62 females) were included in the study. In total, 320 RFs with an ICC >0.75 were evaluated. The proportion of RFs showed significant difference between FBP and 50% ASiR-V, low dose and standard dose, and CE and NE CT scans was 38.4% (123/320), 63.1% (202/320) and 54.1% (173/320), respectively. The radiation dose and contrast agent affected more RFs than the reconstruction algorithm (both P<0.001). In the subgroup analysis of nodule consistency, regardless of changes in the reconstruction algorithms, radiation doses, or contrast agents, the RFs showed significant difference among the pGGNs, PSNs, and SNs (all P<0.001).

Conclusions: The scanning parameters affected the reproducibility of the RFs, and nodules of different consistency were affected differently. The effects of these parameters should be fully considered in radiomic analysis.