Hi!
Of course I am only speculating, BUT--post menopausal bleeding in someone your mother's age is ( unfortunately ) often a sign of uterine cancer. They may be performing the MRI scan to see if there is any spread of cancer outside of the uterus, for example, to the lymph nodes in the pelvis. Sometimes the extent of the disease can determine what type of therapy is best--for example--radiation therapy instead of surgery.
I don't mean to worry you unnecessarily, but I do think you should prepare yourself and your mom for this possibility.
Hope this helps!
Dr B
THANK YOU SO MUCH FOR YOUR PROMPT REPLY IT WAS VERY HELPFUL INFORMATION AND GAVE US A GREATER UNDERSTANDING OF THE SITUATION.THIS IS AN EXCELENT SITE KEEP UP THE GOOD WORK .KIND REGARDS ; HUTCH