|Brain Metastases on
On this film there is a single lesion (white ringed lesion on the right) and just above this is a dark area which is abnormal edema (fluid) due to swelling. This is a common appearance of a single brain met.
The best way to see the cancer is on the post-contrast T1 image and the best way to see the edema is the T2 or FLAIR image (go here and here). MRI will show the tumor in three different views (see here). Often the tumor is not visible unless IV contrast is injected and the pictures repeated (see here, here and here).
|MRI of the brain with single brain metastases from lung cancer, notice how with out contrast (T1 no contrast) you only see an area of vague edema (swelling) on the Flair image the edema is quite prominent and shows up white on this technique, the best view to see the actual tumor is T1 with contrast, where the cancer is much more obvious|