Comparison of Filtered Back Projection, Hybrid Iterative Reconstruction, Model-Based Iterative Reconstruction, and Virtual Monoenergetic Reconstruction Images at Both Low- and Standard-Dose Settings in Measurement of Emphysema Volume and Airway Wall Thickness: A CT Phantom Study

This study aimed to evaluate the accuracy of emphysema volume (EV) and airway measurements (AMs) using different iterative reconstruction (IR) algorithms and virtual monoenergetic images (VME) at low- and standard-dose settings. Computed tomography (CT) scans were obtained on a phantom and reconstructed using various algorithms. EV and airway wall area percentage (WA%) were measured, and absolute percentage measurement errors (APEvol and APEWA%) were calculated. Results showed that IMR-R1 provided the most accurate measurement of EV, while IMR-SP1 was the most accurate for AM in both low- and standard-dose CT. No significant differences were found in APEvol between low- and standard-dose scans for IMR-R1. However, VME at 70 keV showed higher APEvol compared to other algorithms and higher APEWA% compared to all other algorithms. The study concluded that IMR was the most accurate technique for EV and airway measurements. The measurements were performed using the commercial software AVIEW from Coreline Soft, where automatic segmentation and volume quantification were carried out by clicking on each air column.