Hi Kaz,

I wish I could give you a definitive answer, but I'm not qualified. In your position, I'd probably see my GP and ask the question, or phone your named nurse at the hospital (if one has been appointed) and ask.

I guess there's a difference between what the doctor who did the ultrasound was prepared to say was probable and what she would commit to in writing. Ultrasounds are nowhere near as reliable as CT or MRI scans for diagnostic purposes. My own ultrasound was a waste of time as it showed nothing out of the ordinary whilst an endoscope the week after showed a large primary cancer which had been in my Oesophagus for months. Luckily I took my "negative" result with a pinch of salt as I knew the limitations of an ultrasound for this particular cancer. 

Good luck with your MRI scan.

Best wishes

Dave