Radiomics in the evaluation of lung nodules: Intrapatient concordance between full-dose and ultra-low-dose chest computed tomography

Purpose: The purpose of this study was to retrospectively evaluate the quantitative and qualitative intra-patient concordance of pulmonary nodule risk assessment by commercially available radiomics software between full-dose (FD) chest-CT and ultra-low-dose (ULD) chest CT. Materials and methods: Between July 2013 and September 2015, 68 patients (52 men and 16 women; mean age, 65.5 +/- 10.6 [SD] years; range: 35-87 years) with lung nodules >= 5 mm and < 30 mm who underwent the same day FD chest CT (helical acquisition; 120 kV; automated tube current modulation) and ULD chest CT (helical acquisition; 135 kV; 10 mA fixed) were retrospectively included. Each nodule on each acquisition was assessed by a commercial radiomics software providing a similarity malignancy index (mSI), classifying it as benign-like (mSI < 0.1); malignant-like (mSI > 0.9) or undetermined (0.1 <= mSI <= 0.9). Intrapatient qualitative agreement was evaluated with weighted Cohen-Kappa test and quantitative agreement with intraclass correlation coefficient (ICC). Results: Ninety-nine lung nodules with a mean size of 9.14 +/- 4.3 (SD) mm (range: 5-25 mm) in 68 patients (mean 1.46 nodule per patient; range: 1-5) were assessed; mean mSI was 0.429 +/- 0.331 (SD) (range: 0.001-1) with FD chest CT (22/99 [22%] benign-like, 67/99 [68%] undetermined and 10/99 [10%] malignant-like) and mean mSI was 0.487 +/- 0.344 (SD) (range: 0.002-1) with ULD chest CT (20/99 [20%] benign-like, 59/99 [60%] undetermined and 20/99 [20%] malignant-like). Qualitative and quantitative agreement of FD chest CT with ULD chest CT were good with Kappa value of 0.60 (95% CI: 0.46-0.74) and ICC of 0.82 (95% CI: 0.73-0.87), respectively. Conclusion: A good agreement in malignancy similarity index can be obtained between ULD chest CT and FD chest CT using radiomics software. However, further studies must be done with more case material to confirm our results and elucidate the diagnostic capabilities of radiomics software using ULD chest CT for lung nodule characterization by comparison with FD chest CT. (C) 2021 Societe francaise de radiologie. Published by Elsevier Masson SAS. All rights reserved.

Automated summary

The study aimed to evaluate the agreement of pulmonary nodule risk assessment by radiomics software between full-dose and ultra-low-dose chest CT. The results demonstrated good agreement between the two CT doses in assessing the malignancy similarity index of lung nodules.