RD7.2 | Imaging in Sensorineural Hearing Loss — Summary & Reflection

KEY TAKEAWAYS

Imaging in Sensorineural Hearing Loss — Key Points

• Image only the SNHL that needs it: asymmetric/unilateral, sudden, vertiginous, paediatric/congenital, and pre-cochlear-implant cases. Symmetrical age-related (presbycusis) loss does not usually need imaging.
• MRI of the IAM/CPA is the modality of choice for retrocochlear SNHL. Gadolinium-enhanced T1 detects the avidly enhancing vestibular schwannoma ('ice-cream-cone' when it extends into the CPA); heavily T2 CISS/FIESTA screens the IAM and assesses the cochlear nerve.
• HRCT temporal bone is the modality for bony/congenital causes: cochlear malformations, enlarged vestibular aqueduct (EVA) (wider than the posterior semicircular canal / midpoint >~1.5 mm — the commonest imaging-detectable congenital cause of paediatric SNHL), and otosclerosis (pericochlear lucency).
• CPA differential: schwannoma (enhances, IAM-centred) vs meningioma (dural-based, dural tail) vs epidermoid (follows CSF, no enhancement, restricts on DWI).
• Management integration: schwannoma → observation / radiosurgery / microsurgery by size, growth and hearing (serial MRI); EVA → head-trauma avoidance + rehabilitation; pre-implant imaging must confirm a patent cochlea AND a present cochlear nerve — cochlear nerve aplasia contraindicates a conventional cochlear implant (consider auditory brainstem implant).
• MRI for the nerve, CT for the bone — let the clinical pattern choose; in children the two are complementary. ALARA governs CT use; MRI requires safety screening.

REFLECT

On your next ENT, neurology or paediatric posting, notice how an asymmetric hearing loss is handled: is an MRI of the internal auditory meatus requested, and does anyone explain that the concern is a vestibular schwannoma? When a child fails newborn hearing screening, watch how HRCT and MRI are used together — and ask whether the cochlear nerve was specifically commented on, because that single finding can decide the child's whole rehabilitation. Each time you see an SNHL imaging report, trace the chain yourself: what was the pattern, why this modality, what did it show, and how did it change the plan? Building that habit — rather than treating the scan as a reflex — is what turns radiological knowledge into the clinical judgement RD7.2 is testing.