MRI findings of highly suspected Acute brain infarction in a dog.

Dear Colleagues;

This time I wanted to share a very interesting case I saw last time I visited University of Saskatchewan Vet College as Radiologist Locum. This is a canine, adult, acute onset of central neurological signs 2 days prior to presentation. MRI revealed interesting changes in the brain. On T2 and FLAIR weighted images there is a hyperintense lesion in the region of the caudate nucleus with no significant mass effect. First thing came to my mind was an acute brain infarct. SO I took a look at the DWI and ADC to  try to identify any changes suggestive of restricted diffusion of water molecules inside the lesion. The lesion is hyperintense in DWI suggesting restricted diffusion, but wait, we need to rule out the phenomenon called T2-shine through that can mimic true restricted diffusion.   In this case the same lesion was hypointense on ADC indicating that there is  decreased diffusion in the lesion and therefore the most logical explanation / diagnosis is acute brain infarction. But WAIT!!! I took a look the Post contrast (post gad) images and I saw that the same lesion is showing minimal contrast enhancement pattern, mild, however. So I suggested the primary clinician that CSF analysis may be necessary to rule out any inflammatory lesion due to the contrast enhancement pattern. CSF analysis was normal. So acute brain infarcts may uptake contrast medium in MRI no quite frequent and not quite strong as other lesions, however. Combination of DWI/ADC/ accurate history are the key.