Will affected lymph nodes show up on a bilateral breast mri?

No: We cannot tell if a node has cancer within it in the us. In eurpoe they have a special agent which goes into the nodes. They can sometimes tell if a node has cancer in the node. It is used there more for staging of colon cancer. The breast MRI is to detect cancer in your breasts - not the nodes. Of course it can see nodes as enlarged but they can be enlarged from infection and inflamamtion.

Possibly: Mri can evaluate lymph nodes looking for suspiciously enlarged nodes or nodes that have lost their normal "fatty" center . Either of these findings can suggest tumor involvement, but MRI cannot detect cancer in the nodes.

If the: lymph nodes are infiltrated with cancer to the extent that they enlarge or lose their normal shape, they can be detected with MRI. Of course, there are a number of other causes of abnormal lymph nodes(e.g. infectious/inflammatory processes). Microscopic invasion of lymph nodes would generally be undetectable on MRI...the lymph node would look normal.