MRI 
/ˌɛmˌɑɚˈaɪ/ noun
plural MRIs /ˌɛmˌɑɚˈaɪ/ noun medical 1 [noncount] : magnetic resonance imaging
▪ an MRI machine/scanner 2 [count] : a procedure in which magnetic resonance imaging is used
▪ He had an MRI (done) on his knee.
▪ an MRI machine/scanner
▪ He had an MRI (done) on his knee.
