Contrast Volume Reduction in Oncologic Body Imaging Using Dual-Energy CT: A Comparison with Single-Energy CT

Background/Objectives: To evaluate the feasibility of reducing contrast volume in oncologic body imaging using dual-energy CT (DECT) by (1) identifying the optimal virtual monochromatic imaging (VMI) reconstruction with DECT and (2) comparing DECT with reduced iodinated contrast media (ICM) volume to single-energy CT (SECT) with standard ICM volume. Methods: In this retrospective study, we quantitatively and qualitatively compared the image quality of 35 thoraco-abdominopelvic DECT across 9 different virtual monoenergetic image (VMI) levels (from 40 to 80 keV) using reduced volume of ICM (0.3gI/kg of body weight) to determine the optimal keV reconstruction level. Out of these 35 patients, 20 had previously performed SECT with standard ICM volume (0.3gI/kg of body weight + 9gI), enabling protocol comparison. Qualitative analysis included overall image quality, noise, and contrast enhancement by two radiologists. Quantitative analysis included contrast enhancement measurements, contrast-to-noise ratio and signal-to-noise ratio on liver parenchyma and portal vein. ANOVA identified the optimal VMI reconstruction, while t-tests and paired t-tests were used to compare both protocols. Results: VMI60keV provided the highest overall image quality score. DECT with reduced ICM volume demonstrated higher contrast enhancement and lower noise than SECT with standard ICM volume (p <0.001). No statistical difference was found in overall image quality between the two protocols (p = 0.290). Conclusions: VMI60keV with reduced contrast volume provides higher contrast and lower noise compared to SECT at standard contrast volume. DECT using reduced ICM volume is the technique of choice for oncologic body CT.