MRI vs biopsy for debris in ducts

I had DCIS 4 years ago in rt. breast and now have enlarged ducts in left breast.  The radiologist suggested possilby getting an MRI and/or biopsy.  Does an MRI identify the type of cells that are in the duct or is biopsy the only way to know for sure?  I don't want added medical expense if they are going to recommend a biopsy later, anyway.  Also, what do they usually do about debris in the ducts?  

[japdip]

They are entirely different things as you well know. A biopsy of some type is the only way to arrive at a definite diagnosis. Debris is usually dead skin cells. MRI is a more sensitive type of imagery but can't test the area for Pathology.   Regards ....

[nasy]

Thanks.  My dr's office just called to say they are ordering a MRI so I guess that's the course I'm supposed to take.  Haven't acutally talked with the dr about it.  We'll see what shows up.

--nasy