Diagnostic value of dual-energy CT reconstructions in acute appendicitis in an emergency setting: A prospective study

Objective: To evaluate the diagnostic performance of dual-energy computed tomography (DECT) in acute appendicitis by comparing attenuation characteristics across different virtual monoenergetic energy levels, virtual non-contrast, overlay, and mixed image reconstructions. Methods: All participants underwent DECT using a dual-source scanner. Appendiceal diameter, periappendiceal findings, and attenuation values obtained from iodine maps, virtual non-contrast, overlay, mixed images, and 40, 80, and 190 keV virtual monoenergetic images were recorded. Diagnostic performance was evaluated using receiver operating characteristic analysis, and interobserver agreement was assessed using a two-way random intraclass correlation coefficient. Results: In this prospective observational case-control study, 20 patients with surgically or clinically confirmed acute appendicitis and 20 control subjects without appendicitis were included. Appendiceal diameter and all DECT-derived attenuation parameters were significantly higher in patients with acute appendicitis compared with controls ( P < .001). The highest diagnostic accuracy was achieved with 40 keV virtual monoenergetic images (AUC = 0.998), followed by appendiceal diameter (AUC = 0.994) and mixed images (AUC = 0.973). Low-keV reconstructions provided markedly improved lesion conspicuity. Periappendiceal fat stranding demonstrated high diagnostic performance (sensitivity 0.95, specificity 1.0). Interobserver agreement for attenuation measurements was excellent (intraclass correlation coefficient = 0.887). Conclusions: Low-keV (40 keV) virtual monoenergetic DECT imaging provides very high diagnostic accuracy for the detection of acute appendicitis and outperforms higher-keV reconstructions and other DECT image types. When combined with conventional CT findings such as appendiceal diameter and periappendiceal inflammatory changes, DECT-derived attenuation analysis represents a reliable and reproducible tool that may enhance diagnostic confidence in emergency imaging.