Daisy,
I don't mean to be a pain and I certainly don't want to cause you undue stress, but I do feel it is extremely important to get an MRI
before the surgery. Heather's tumor didn't even show up on the CT scan and I have heard from many people that the MRI seems to pick up more stuff. I know you don't want to postpone the surgery, but I would strongly suggest calling the surgeon ASAP and get this resolved before monday. I am convinced Heather's second tumor was not a recurrence, but was present from the beginning. If she had had an MRI and the tumor had been detected, her treatment would have been different and perhaps she would still be alive.
I realize your case is entirely different, but it just makes good sense to know exactly what you are dealing with before starting treatment. Best wishes.
Rainbows & hugs,
Rosie