Also know as CAT scan or Computerized Axial Tomography, patients find this type of scan less claustrophobic than an MRI scan as the tunnel on a CT machine is much shorter than the tunnel on an MRI scanner.
Computed Tomography scans are a three dimensional "window" into the body through which doctors can see brain, spine, joint and internal organs.
A CT scan consists of a highly sensitive X-ray beam that is focused on a special plane of the body. As this beam passes through the body, it is picked up by a detector, which feeds the information it receives into a computer. The computer analyzes the information on the basis of tissue density.
CT scans are preferred where bone details are of paramount importance (long bones, spine, skull) whereas MRI’s produce much better soft tissue detail (brain, spinal cord, etc).