The value of dual-energy spectral CT in differentiating the pathological grades of T1-size lung adenocarcinoma.

BACKGROUND

Accurate preoperative diagnosis of pathological grades in T1-sized lung adenocarcinoma (LUAD) is crucial for clinical decision-making. The study aimed to investigate the value of dual-energy computed tomography (DECT) in distinguishing pathological grades in newly diagnosed LUAD lesions ≤3 cm in size.

METHODS

From October 2018 to January 2022, 137 patients with 161 pathologically confirmed LUAD lesions (≤3 cm) having received DECT were retrospectively enrolled with clinical information collected (low-grade: high-grade =41:120). CT values of monochromatic images at 40-140 keV, effective atomic number (Z), and iodine concentration of lesion (IC) on plain, arterial phase (AP), and venous phase (VP) images were measured. Iodine concentration difference (ICD), normalized iodine concentration (NIC), and slope of the spectral curve (λ) were further calculated. Difference tests and multiple stepwise regression were utilized to predict grades. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic efficacy of the clinical model, spectral model, and combined model.

RESULTS

There were significant differences in CT values of 40-140 keV and Z between these two groups for the plain, AP, and VP images (all P<0.001), but not in IC, ICD, NIC, and λ (all P>0.05). Stepwise regression showed that CT on plain spectral CT, CT on AP, and CT on VP are independently significant factors. The combined model achieved the best performance [area under the curve (AUC) =0.825], which significantly outperformed the clinical model (AUC =0.772, P=0.03), but not the spectral CT model (AUC =0.774, P=0.07).

CONCLUSIONS

In addition to clinical features, single-energy CT values hold the potential to differentiate the pathological grade of T1-size LUAD.