Depends. If the aphasia is due to an infarct the brain will look different.
Maybe. Might show the stroke.
Maybe. Following a stroke, hemorrhage, infection or trauma may leave structural alterations visible on MRI scans. Some inherited aphasias are also likely to be visualized. However many cases of aphasia will not be visualizable on standard imagery. Functional MRI and spect might be useful in visualizing some aphasias.
Possibly.... If one had a tumor or stroke involving certain areas of the brain (e.g. Broca's area) you may develop an aphasia and would see an abnormality on mri. However, it is also possible to have an aphasia with no MRI abnormality.