A ct scan is a study which allows one to see the body in cross section.  X-rays are used in this scan, and using a sophisticated computer, by sending the beams through the body in many different directions, the cross sectional anatomy of the body is reconstructed.  A ct scan is excellent at showing detail of bone,  blood and air, but not as good with certain types of soft tissue.  A magnetic resonance imaging (mri) is much better at showing soft tissue.  The same precautions which apply to the use of x-rays also apply to the use of ct scanning.  Pregnant women should notify their physician or ct technician.  While some patients may not tolerate a closed  mri scan because of the  confined space,  patients rarely have any kind of difficulty tolerating a ct scan because the opening is much larger, and the length of the tunnel much smaller.