Emergency radiology has gained a widespread and rapid development as a subspecialty of diagnostic imaging. Imaging of patients in the emergency department has the particularity of addressing various acute pathologies requiring a fast and precise diagnosis in order to provide a prompt and accurate medical or surgical management. Among all imaging methods, CT and sonography examinations became the pillars of imaging in emergency situations; these techniques also constitute the fundamentals of imaging in our emergency radiology unit at the Geneva University Hospital. Therefore, as part of the academic research group in emergency radiology, my projects were centered on the clinical evaluation of new CT and sonography methods, in order to improve and accelerate the management of patients with various acute clinical conditions. These projects reflect the variety of my research interests in emergency imaging; they address the use of contrast-enhanced sonography in abdominal trauma, the role of total-body CT in polytrauma patients, the clinical utilization of low-dose CT abdominal examinations, the set-up of clinico-radiological scores helpful for the clinicians in the management of frequent acute abdominal pathologies, such as diverticulitis and small-bowel obstruction and the development of new informatics tools for the characterization of interstitial lung diseases. The current habilitation thesis is structured in three parts. The introduction describes the advent and the gradual development of emergency radiology, with enhancement on my research projects leading to implementation of new sonographic and computed-tomography techniques in our emergency radiology section. The second part consists of short presentations of the most representative publications of my research activity, further detailed in the appendix section. The final part provides an overview of my current research projects, focused on clinical evaluation of new CT technologies, namely dual-energy techniques and iterative image reconstructions protocols.