I recently had an mri for a possible acoustic neuroma. i have not received the results, but my ent has them, and wants me to go for ct why?

Ask ordering Doc: CT shows bone detail much better than MRI, so they are complementary modalities. The MRI results must be interpreted between your doc and the radiologist. Your ENT should explain why he wants the CT as a list of dx. possibilities from the MRI exists. You should know it before having the CT, just because there is x ray exposure and slight contrast risk to the CT but CT is often warranted for a dx.