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Clarification of Scans
A CT is a very detailed xray taken my moving the xray source in three dimensions and utiliziig computer programs to reconstruct the body part in three dimensions--when viewed it looks as if someone sliced and diced you either top from bottom, right from left or front from back. It utilizes x rays and shows bones best, much better than soft tissues (ligament, muscle, brain, etc)It can be done with or without contrast, often iodine-based.
An MRI involves no irradiation, only magnetism. When a magnetic field is turned on it takes all the electrons in all the atoms in your body and makes the electrons spin a different way just for a second, when they go back to spinning the same way an image can be generated. It often shows areas which have more or less water in them as different densities and shows SOFT TISSUES BETTER THAN BONE. Unfortunately you cannot take as small of slices with it as with CTs, but contrast utilized with it is not iodine-based, it is usually gadolinium.
A PET scan involves being injected with radioactivity attached to a glucose like molecule, which shows areas which have high metabolic rates (burning lots of energy). These can be areas of infection, inflammation or tumor.
It is best done as a PET/CT (simulataneous PET and CT scan, mainly teaching hospitals and comprehensive cancer centers have this capabillity)
as otherwise it only shows the abnormality in two dimensions and not three, so it is hard to interpret exactly what structure is involved
Which scan is better depends on what they are looking for and how small it might be ie, you could miss a 1 mm nodule in a lung if your cuts sliced just above and just below it on an MRI. It might show up on a CT, but the resolution of a PET is such that a 2mm lung nodule would not show up. The resolution of both CTs and MRIs is getting better and better, so try to be treated at a facility which constantly updates to the best machinery/software.
A MUGA scan is another test where one is injected with radioactivity in order to see how efficiently the heart is pumping ( Left ventricular ejection fraction). The same information can be gained from a well-done cardiac echo without the radioactivity, but again it depends on the equipment and capabillity of the health care center you are being treated at.
NED stands for "no evidence of disease" that is, they can't find any with their searching. Originally it meant nothing showed up on xray, then it meant nothing showed up on CT or bone scans, then it meant nothing showed up on MRI or PET scan. As our technology progresses the meaning of NED changes as well.
Never be afraid to ask!!!!
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