Causes of unilateral sensorineural hearing loss screened by high-resolution fast spin echo magnetic resonance imaging: Review of 1,070 consecutive cases

Objective: Evaluation of the ability of screening high resolution, nonenhanced, fast spin echo (FSE) T2-weighted magnetic resonance imaging (MRI) of the internal auditory canal (LAC) and cerebellopontine angle (CPA) to detect nonacoustic schwannoma causes of unilateral sensorineural hearing loss (SNHL). FSE-MRI is equally sensitive in detecting acoustic (vestibular) schwannoma as gadolinium-enhanced MRI, but sensitivity to other causes of hearing loss is unknown. Study Design: Retrospective review of screening FSE-MRI studies. Setting: Academic otology/neurotology and neuroradiology practices. Patients: There were 1,070 patients with unilateral SNHL who underwent radiologic screening for retrocochlear pathology. Results: Normal findings were found in 944 cases. Typical (acoustic) vestibular schwannoma were found in 56 patients. Seventy additional lesions were identified: 27 CPA lesions, 29 inner ear lesions, and 12 intraaxial lesions including 9 infarctions, 1 multiple sclerosis case, 1 mesial temporal lobe sclerosis, and 1 colloid cyst. Conclusions: High-resolution T2 FSE-MRI of the IAC and CPA is a highly sensitive screening cool for unilateral SNHL, which can detect a variety of lesions in addition to vestibular schwannomas. To our knowledge in 2 years of follow-up in these patients screened for IAC/CPA lesions, no other lesions causing SNHL have been found. High-resolution FSE screening technique, used in conjunction with appropriate clinical prescreening and referral, can provide an equally sensitive method of evaluating unilateral SNHL compared to gadolinium-enhanced T1 MRI while reducing costs and providing distinct advantages in evaluating nonacoustic schwannoma causes of SNHL.