Spectral and Dual-Energy CT in Emergency Imaging: A Technical Review of Image Quality, Dose Reduction, and Artifact Mitigation

Dual-energy and spectral computed tomography (DECT/spectral CT) extend conventional single-energy computed tomography (SECT) by measuring attenuation at two or more energy levels. This enables material decomposition, virtual monoenergetic imaging, and quantitative iodine mapping. In emergency radiology, these techniques may improve lesion visibility, reduce additional examinations and contrast medium requirements, and mitigate metal and beam-hardening artifacts when rapid and accurate diagnosis is required. This narrative review describes the underlying physical principles and available source-based, detector-based, and photon-counting technologies. It examines image quality, radiation dose, artifact reduction, and practical applications in emergency imaging.