special subjects
Computed Tomography (CT)
Uses of CT
CT provides better differentiation between various soft-tissue densities than do x-rays. Because CT provides so much more information, it is preferred to conventional x-rays for imaging most intracranial, head and neck, spinal, intrathoracic, and intra-abdominal structures. Three-dimensional images of lesions can help surgeons plan surgery. CT is the most accurate study for detecting and localizing Urinary Calculi . CT may be done with or without Radiographic Contrast Agents and Contrast Reactions . Noncontrast CTis used To detect acute hemorrhage in the brain, urinary calculi, and lung nodules To characterize bone fractures and other skeletal abnormalities IV contrastis used To improve imaging of tumors, infection, inflammation, and trauma in soft tissues To assess the vascular system, as when Pulmonary Embolism (PE) , Oral or occasionally rectal contrast is used for abdominal imaging; sometimes gas is used to distend the lower gastrointestinal (GI) tract and make it more visible. Contrast in the GI tract helps distinguish the GI tract from surrounding structures. Standard oral contrast is barium-based, but low-osmolar iodinated contrast should be used when intestinal perforation is suspected. 