[Lani]

MRI is based on magnetism and looks at the water content of tissues and thus shows soft tissues better (it also is exquisitely sensitive to detecting some heavy metals such as iron--due to their magnetic properties, such that nanomolecules containing iron can create easy to see abnormalities even whent the structure is very small--but new contrast agents based on fusing herceptin to iron-containing nanomolecules are still experimental and not yet appproved for people (they theoretically could show micrometastatic disease that is her2+) This property is not entirely useless until these agents are approved as . iron deposits , wuch as in in hemachromatosis, a disease where there are abnormal iron deposits in internal organs, shows up easily)

CT is based on the same radiation as xrays and shows bones (hard tissues) in more detail

CTs create images that are sliced more thinly than MRI (due to technologic challenges) and thus show smaller abnormalities than could be detected on MRI