Dual-energy CT Virtual Non-contrast as a Low-radiation Alternative to True Non-contrast in Crohn’s Disease Enterography

Abstract: Objective: To explore the application value of dual-energy CT virtual non-contrast (VNC) instead of true non-contrast (TNC) in reducing the radiation dose of small intestine radiography in Crohn's disease. Methods: Dual-energy enterography images of 53 patients with Crohn's disease in the First Affiliated Hospital of Nanjing Medical University from June 2024 to December 2024 were obtained. Virtual non-contrast images of the arterial phase and venous phase were reconstructed using dual-energy analysis software. One-way analysis of variance was used to evaluate the CT values, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of conventional plain scan and virtual plain scan images in the arterial and venous phases. The image quality was subjectively evaluated by the 5-point method and analyzed by the rank sum test. The subjective image quality scores of TNC, VNCa and VNCv were 4 (4, 5), 4 (4, 5) and 4 (4, 5) respectively, and the difference was not statistically significant. There was no statistically significant difference in the CT values of the diseased intestinal wall, normal intestinal wall, inferior vena cava, erector spinae muscle and liver among TNC, VNCa and VNCv. The SNR values of the diseased intestinal wall, normal intestinal wall, abdominal aorta, inferior vena cava and liver were statistically significant, and the SNR values of VNCa and VNCv were both higher than those of TNC. There was no statistically significant difference in the CNR values among the diseased intestinal wall, normal intestinal wall, inferior vena cava and liver. The radiation dose of VNCv scan is approximately 30% lower than that of TNC CTE scan. Conclusion: The virtual non-contrast of dual-energy CT instead of the true non-contrast can reduce the radiation dose of enterography in Crohn's disease while ensuring image quality, and can be promoted in clinical applications.