A diagnosis of emergency clinical conditions, made based on medical history, physical examination, and laboratory tests, results in only a minimal percentage of patients who access emergency departments. Computed tomography (CT) is an extremely rapid and effective modality for evaluating patients with emergency-urgent thoraco-abdominal pathologies. It is useful for diagnosing the disease, demonstrating its complications, and providing essential information to undertake the most appropriate treatment strategy. The identification and characterization of the different emergency pathologies is strictly dependent not only on the CT scan parameters but also on the injection of contrast medium. To obtain optimal vascular and parenchymal enhancement, some parameters must be taken into consideration: patient-related factors (sex, age, body weight, and cardiac output) and contrast media injection protocols (iodine dose and contrast medium administration rate). In the contrastographic study, although the portal phase is the most used for the diagnosis of various pathologies of the thorax and abdomen, there is however an improvement in diagnostic accuracy when using a multiphasic study. With current CT equipment, it is possible to obtain optimal image quality by reducing the exposure to ionizing radiation.