CT scan, conceptual computer artwork. Computed tomography (CT), also known as computed axial tomography (CAT), is a medical imaging technique where an image of internal organs is built up from a series of x-ray scans. Single lines can generate a 2D image, and these can be used to build a 3D model. A computer manipulates the data from each of the sections. This is an abdominal scan, with the lines across the body representing the sections.