As soon as Computerized Tomography or CT scans became available in the 1970s, they reformed the practice of neurology. They did the scans by transmitting x-ray streams all the way through the head at different positions & accumulating the x-ray streams on the other side that was not absorbed by the head. A sequence of images come in to view on a computer monitor or on an x-ray plate as if the head had been sliced from side to side by a sizable salami cutter & the slices were arranged out horizontally & in series.

After that, in the 1980s Magnetic Resonance Imaging or MRI scans came in to the picture & astounded the medical society by not taking an picture of the brain itself, but by doing so in a brand spanking new way. MRIs concentrate on water molecules, as an alternative to imaging the degree to which the various parts of the head absorb x-rays. To be more specific, MRIs represent the speed at which rotating hydrogen atoms of water molecules inside various parts of the brain either line up or fall out of arrangement with a powerful magnetic field. These different values of de-magnetization or magnetization are inputted in to a computer. Slice like images are formed in a sequence & put on view on a computer screen or x-ray type film in hues of grey. Irregular compositions, like brain tumors or the signs of multiple sclerosis, are shown in their own hues of grey & are also identifiable by their contours & positions. Getting hold of a different set of images after a hypodermal injection of gadolinium, which is the MRI equivalent of x-ray dye, also adds to analytical information.

For a patient, the incident of having a CT & of having an MRI much looks a lot like each other. In both situations the patient lies flat on a plane table that moves in to & out of a hole in the scanner that looks a lot like an oversize doughnut hole. In the MRI machine the doughnut hole is narrower, so patients suffering from claustrophobia must notify their doctors if this might be a hitch. Noise is also an issue with the MRI machine. A loud noise is produced every time the radio frequency coils are turned on & off. For either of these seven scans the technologist may need to inject a needle in the patient’s vein to dispense a distinct substance.

A situation in which MRIs are fundamentally not done is when the patient has a heart pacemaker. This is for the reason that the MRI machine’s magnet might disturb the pacemaker & cease the heart. No picture is so essential & important that this peril would be worth taking. Another situation in which an MRI is evaded is when the patient is gravely ill. A serious patient can be effectively examined & sustained while getting a CT scan, but not while getting an MRI.