Is there sometimes dye used in an MRI? What is this test used to diagnose/see versus for example a PET scan? TIA.
In: Technology
MRI scans are physically mapping the concentration of hydrogen, what this means for the human body is mostly measuring water and fat. They produce a structural image for example in the brain you can see all of the grey and white matter (and they appear different which is useful diagnostically). They’re using for diagnosing pretty much anything which causes a structural change in the brain like Alzheimer’s.
MRI does occasionally use contrast agents but it’s rare as most MRI imaging doesn’t require it.
A PET scan on the other hand measures the distribution of the tracer you inject, eg some sugar analog with a radioactive isotope. This lets you map metabolic processes, seeing where that tracer gets concentrated in the body. For example cancer cells use a tonne of sugar because they are growing so much, so if you image them with a PET scan then they can be easily identified.
My experience in this is from studying physics involving medical imaging so someone with a medical background may be able to elaborate on exactly what they can be used for.
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