Wernicke's area is responsible for

The Wernicke's area is located in the temporal lobe on the left side of the brain and is responsible for the comprehension of speech (Broca's area is related to the production of speech). Language development or usage can be seriously impaired by damage to this areaof the brain.

Unlike  ct scans, which use x-rays,  mri scans  use powerful magnetic fields and radio frequency pulses to produce detailed pictures of organs, soft tissues, bone and other internal body structures.  differences between  normal and abnormal tissue is often clearer on an  mri  image than a  ct.you can see more with a mri scan. for example on an mri you can see internal bleeding.