Could The Vertigo Be Due To Brain Tumor?

i had an mri on wed. and the dr. won't give me the results for 2wks when my next appt is. He was looking for a brain tumor or MS b/c I have had vertigo for 4wks now and he said he doesn't think it is from my ear b/c my vertigo is like trying to walk on a rocking boat. If I did have a brain tumor, do doctors normally wait until your follow up to tell me or do they usually call right away?