J Neurol Surg B Skull Base 2012; 73 - A359
DOI: 10.1055/s-0032-1314273

Incidental Findings on MRI Internal Acoustic Meatus (IAM) in ENT Outpatients

M. J. Lee 1, S. Dawes 1, J. Douglas 1 O. Al Hamarneh 1(presenter), R. Bickerton 1, C. Coulson 1
  • 1Warwick, UK

Objective: To establish the incidence of incidental findings on MRI IAM and to establish the rate of diagnosis of vestibular schwannoma (VS) on MRI IAM.

Design: Retrospective review.

Patients/Materials and Methods: All patients undergoing first MRI IAM for symptoms of hearing loss, tinnitus, or other symptoms associated with VS. A two-year period was reviewed at a district general hospital (DGH), and a 6-month period was reviewed at a tertiary ENT center. Indication for imaging was recorded from clinic notes, and imaging reports were reviewed.

Results: We identified 1066 scans (657 at a DGH; 409 at a tertiary center). VS was diagnosed in 1.7% of MR scans. This was consistent between the two trusts. Incidental findings occurred in 18% of the DGH MRIs and 36% of the tertiary center's MRIs. Ischemia and sinus disease were the two most common incidental findings, occurring overall in 9.7% and 4.3% of MRI IAM scans, respectively.

Conclusion: Pick up rate of VS on MRI IAMs between the two trusts was consistent at 1.7%. This is a useful number to the clinician and patient when counselling occurs in outpatients. There was a high rate of incidental findings on MRI IAMs, which will affect future follow-up and may trigger further investigations in an otherwise asymptomatic patient.