Reliability of MRI without contrast

[jtg1]

I have not been diagnosed with AN, but have most of the symptoms:  Tinnitus and fullness/pressure in my right ear (for several years); within the last 10 months, have had 2 major vertigo attacks; numbness on the right side of my face that has gradually increased in duration and intensity (it is now constant); dizziness, which started out infrequently but now consists of a constant 'head rush'.  Hearing in my right ear has diminished somewhat.  Most concerning, I seem to be having some memory issues and inability to focus (perhaps because the symptoms are now quite distracting).

As for treatment:  I had an MRI without contrast after my first vertigo attack; the results were negative for hemorrhage or cranial mass.  Since then, I have been to an ENT, who did hearing tests and VNG - I was then referred to a neurologist (MRA, medication, occipital nerve block, jaw x-ray for potential TMJ issues), but has dismissed my concerns about acoustic neuroma due to the negative MRI.

I am by no means convinced I have AN, but from what I have been reading it sounds like AN should not be eliminated as a possible diagnosis based on an MRI without contrast.  Also, it is not clear to me whether AN would show up on an MRA.  Are there any formal, documented studies that address the reliability/unreliability of MRI/MRA without contrast?  If this is the case, I would like to forward to my neurologist. 

[Blw]

I think there is a thread around here on this topic. Perhaps search the word contrast. I believe there are some cases where no contrast has been reported to work, but everyone has to know they are looking for an AN and you may even need to use the 3T imager (more powerful). Also, I don't think it would pick up a smaller tumor without contrast. If your doctors will not agree to it, perhaps see if you can find an ENT at a larger clinic or center. They have a ton of test they can run, and there is a specific one for facial nerve  (electroneurography (ENoG)) that is quantitative and I believe definitive of facial nerve problems.

[PaulW]

New MRI's can detect small AN's without contrast, however if something is detected they will give you the contrast to determine what sort of mass it is.
For instance if it doesn't light up it maybe a meningioma, while if it does light up and Acoustic Neuroma is more likely..

The quality of the imaging chain and experience of the reporting radiologist are key factors determining the efficacy of a non-contrast screening strategy. Based on a cost-effectiveness model developed to reflect UK practice it was concluded that a diagnostic algorithm that deploys non-contrast MR imaging as an initial imaging screen in the investigation of acoustic neuroma is less costly than and likely to be as effective as available contrast MR imaging.

http://www.ncbi.nlm.nih.gov/pubmed/19358774

[PaulW]

Here is a better link...
They successfully detected a 2mm AN without contrast..

Screening noncontrast MR imaging using a combination of axial CISS and coronal T2WI sequences can detect small internal auditory canal lesions with 100% sensitivity and excellent interobserver agreement.

http://www.ncbi.nlm.nih.gov/pubmed/25034778