Yes, Tinks, I was first diagnosed with a 2.0cm AN in January, 2008 via an MRI with contrast. (See my signature at the bottom for the rest of my history.) The vast majority of the relatively rare acoustic neuromas are slow growing.
That being said, I had an MRI without contrast 14 months earlier (November, 2006) that was perfectly clear of any tumor. Paul is right, though, that a tumor the size of mine would normally have been detectable on an MRI without contrast. My neurosurgeon thoroughly examined the CD of my November, 2006 MRI and compared it with the January, 2008 MRI and could find absolutely no sign of it on the 2006 scan. Therefore, he felt I had a rare, rapidly growing AN. Indeed, it grew from 2.0 cm on the MRI to 2.6 cm at surgery three weeks later.
Not telling you this to scare you, but it can happen. Paul is right that most people do not have one, but there are rare instances where a subsequent MRI will show an AN.
Thoughts and prayers for an accurate diagnosis and successful treatment.
Clarice