Update on Imaging of Hearing Loss

In the imaging evaluation of hearing loss, the radiologic examination is complementary to the physical examination. The clinical evaluation includes not only an accurate history of the hearing loss itself (unilateral or bilateral, slow onset or fast onset, etc.) but also the patient's medical history (possible trauma, ototoxic drugs, associated facial nerve palsies, etc.). Hearing loss can be described as sensorineural, conductive, or mixed, and this will guide the choice of imaging modality to correlate with the clinical history and symptoms. In this chapter, we will review the more common hearing loss entities and divide these pathologies into those presenting with sensorineural hearing loss (SNHL), conductive hearing loss (CHL), and mixed hearing loss (MHL). The pathologies for SNHL and CHL will be further grouped and discussed as either congenital or acquired entities. In very simplistic terms, CHL is frequently initially evaluated with CT, whereas SNHL is most frequently initially evaluated with MRI. When reviewing the imaging studies, a systematic “outside-in” approach along the hearing pathway is helpful, from the external anatomic structures to the internal structures.