A C-Scan reveals bones better than MRI. It may reveal a widening of the IAC, Inner Auditory Canal, which would be indicative of an AN. I've read where occassionally a C-Scan will miss an AN up to 1.5 cm. It is a cheaper prescreening test ordered by some ENTs.
Needed, is a closed tube MRI to accurately image an AN. The scanner must be at least T-3 weighted and a high resolution scan with gadolinium contrast be taken between the IAC axial plane.
Open MRIs are not sufficient for imaging ANs in all situations. They are generally T-1 weighted, T, Tesla, being the measurement unit of magnetism.
Best wishes here. I would stand my ground for an MRI to be on the safe side.
I may be a little premature in writing this as I only have been diagnosed via symptoms and audiogram tests. My ENT sent me for a CT scan due to my defibrilator preventing me from getting a MRI. Question is...Can a CT scan catch an AN 100%? Symptoms are gradual left hearing loss, bad tinnitus, and 2 severe occurances of vertigo/sweating/nausea. CT scan was without contrast.