Dual-energy CT pulmonary angiography with reduced contrast media volume: Quantitative image quality compared with single-energy CT

Abstract

Objective This study aimed to compare the quantitative image quality and radiation exposure of dual-energy CT pulmonary angiography (CTPA) with reduced contrast media volume versus conventional single-energy CTPA.Materials and methodsThis single-centre prospective observational study included patients who underwent CTPA with a clinical suspicion of pulmonary embolism between August 2024 and March 2025. Of the 177 patients included in the final analysis, 92 patients underwent dual-energy CTPA with 45 mL of contrast media, and 85 patients underwent single-energy CTPA with 60 mL of contrast media. Attenuation and image noise were measured in five pulmonary artery segments (main pulmonary artery, left and right pulmonary arteries, and right and left posterior basal segmental arteries). Primary endpoints were signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR), which were calculated from these five segments. Attenuation, SNR, CNR, along with radiation exposure metrics, such as volume computed tomography dose index (CTDIvol), dose length product (DLP), and size-specific dose estimate (SSDE) were compared between the dual-energy CTPA group and single-energy CTPA group.ResultsCompared with conventional single-energy CTPA, dual-energy CTPA with a significant reduction in contrast media, demonstrated comparable attenuation in all five pulmonary artery segments (all p>0.05), higher pooled SNR, and higher CNR across all pulmonary artery segments (all p<0.05). Radiation exposure parameters, CTDIvol, DLP and SSDE, were also comparable between dual-energy CTPA and single-energy CTPA (all p>0.05).ConclusionDual-energy CTPA enables a 25 % reduction in contrast media volume compared to conventional single-energy CTPA, while providing improved quantitative image quality without increasing radiation exposure.