Quantifying whole lung iron oxide deposition with dual-energy CT for diagnosis of arc-welders' pneumoconiosis.

Abstract

Accurately quantify pulmonary iron oxide by dual-energy CT (DECT) and evaluate its diagnostic potential in arc-welders' pneumoconiosis (AWP). This prospective, single‑center diagnostic accuracy study (April 2024 to October 2024) included three groups: welders, mimic-imaging, and healthy controls. DECT quantified whole-lung Fe₂O₃ density (mg/cm³) [D_Fe2O3] and total Fe₂O₃ mass (mg) [Total-Fe₂O₃]. Maximal diameter and D_Fe2O3 for the largest nodule and the subjective grading on imaging features were also collected. Receiver operating characteristic (ROC) analysis was used to evaluate diagnostic performance. In vitro experiments, ten 30 mL tubes containing Fe₂O₃ solutions (0-12 mg/mL, in triplicate) were scanned immediately after preparation. ROIs were analyzed, and averaged values were linearly regressed with actual concentrations. In vitro experiments showed a strong correlation between measured and actual Fe₂O₃ concentrations (r = 1.00, p < 0.01). One hundred forty participants were included: 50 welders (mean age, 44.5 years ± 20.25；47 male), 35 mimic-imaging controls (mean age, 51.0 years ± 10.0; 34 male), and 55 healthy controls (mean age, 48.0 years ± 19.0; 41 male). Welders had higher <math xmlns="http://www.w3.org/1998/Math/MathML"> <msub><mrow><mi>D</mi></mrow> <mrow> <msub><mrow><mi>Fe</mi></mrow> <mrow><mn>2</mn></mrow> </msub> <msub><mrow><mi>O</mi></mrow> <mrow><mn>3</mn></mrow> </msub> </mrow> </msub> </math> (0.934 ± 0.50 mg/cm³) and Total-Fe₂O₃ (4082.6 ± 2503.1 mg) than mimic (0.346 ± 0.28 mg/cm³; 1376.1 ± 1514.9 mg) and healthy controls (0.371 ± 0.24 mg/cm³; 1374.1 ± 896.2 mg) (all p < 0.001). D_Fe2O3 distinguished welders from healthy controls with AUC 0.911 [95% CI: 0.840-0.958], sensitivity 82.0%, specificity 92.7%, and from mimic controls with AUC 0.900 [95% CI: 0.816-0.954], sensitivity 84.0%, specificity 82.9%. In vitro experiments showed a strong correlation (r = 1.00, p < 0.01) between actual and measured concentrations. Quantification of pulmonary iron oxide deposition using DECT can aid in the differential diagnosis of AWP. Question Due to overlapping imaging features between AWP and other diffuse pulmonary diseases, a definitive diagnosis is difficult based solely on imaging. Findings Pulmonary D_Fe2O3 and Total-Fe₂O₃ by DECT showed high diagnostic accuracy (AUCs > 0.90) for distinguishing welders' pneumoconiosis from both mimic-imaging and healthy controls. Clinical relevance Non-invasive DECT Fe₂O₃ quantification improves the differential diagnosis of AWP, and enables targeted monitoring of occupational exposure, enhancing patient outcomes and occupational health management.