Computed Tomography (CT)
Computed tomography (CT) or CAT scan, uses a rotating X ray tube and computer to obtain thin sections of the body. It is especially useful in cases of head injury and stroke. It is best investigation to detect acute hemorrhage and calcification anywhere in the body. It is also good to evaluate cortical bone.
Although it is non-invasive it uses ionizing radiation. although three dimensional reconstructions are possible it doesnt give direct multiplanar images.
It may require use of an iodianted contrast which may be toxic to kidneys in very high doses and can cause idiosynratic reactions in some (especially asthmatics, diabetics, cardiac patients etc). Metallic objects like coins, dentures etc may cause artefacts in the images.
Women should inform if there is any possibility that they are pregnant, as the examination involves radiation which is harmful to the fetus.