Frequency and Clinical Significance of Incidental Findings Detected in Internal Acoustic Canal Magnetic Resonance Imaging of Patients with Audiovestibular Symptoms.

Objectives: Retrocochlear pathology associated with audiovestibular symptoms is detected in very few of the patients, and most of the internal acoustic canal magnetic resonance imaging examinations (IAC-MRIs) are either completely normal or include accompanying incidental findings (IFs). The aim of our study is to reveal the presence and frequency of IFs in IAC-MRIs, together with retrocochlear lesions. In addition, we intend to emphasize the clinical importance of these IFs.

Methods: A retrospective analysis of 374 serial IAC-MRI scans.

Results: Gender distribution: 201 males and 173 females. Age range: 2-82 years. Seventy-two scans (19.25%) were totally normal. Fifteen scans (4.01%) demonstrated only pontocerebellar angle findings (PCAFs). The presence of PCAF and IF was together in 57 scans (15.24%). In 230 (61.50%) of the scans, only IFs were present. The incidence of IFs in all IAC-MRIs was 76.74% (287 of 374). Critical findings that may require clinical further evaluation and examination were present in 34 scans (9.09%). IFs that did not require further examination were observed in 253 scans (67.65%).

Conclusion: Various IFs can be detected with IAC-MRI that may cause similar symptoms with PCAF. And unfortunately, some of these IFs may be of very high clinical importance. All referral clinicians should know well that these audiovestibular symptoms can appear as IFs anywhere in the auditory pathway, and how they should be followed in their clinical approach.