MRI vs tomography

MRI and tomography both are nouns.

Word	Noun	Adjective	Verb	Adverb
MRI	Yes	No	No	No
tomography	Yes	No	No	No

As nouns, tomography is a hypernym of MRI; that is, tomography is a word with a broader meaning than MRI:

MRI: the use of nuclear magnetic resonance of protons to produce proton density images
tomography: (medicine) obtaining pictures of the interior of the body

Other hypernyms of MRI include imaging.

MRI (noun)	tomography (noun)
the use of nuclear magnetic resonance of protons to produce proton density images	(medicine) obtaining pictures of the interior of the body