Audiogram — Sudden Sensorineural Hearing Loss

A 52-year-old man presents with sudden unilateral hearing loss noticed on waking this morning. Audiometry shows the pattern marked **A** in the diagram — severe sensorineural hearing loss across all frequencies on the left, with normal hearing on the right (marked **B**). The air-bone gap is absent (marked **C**), and symptom onset was within 72 hours (marked **D**). The patient reports aural fullness and tinnitus but denies vertigo. Which of the following is the MOST appropriate immediate next step in management?

A 52-year-old man presents with sudden onset severe unilateral hearing loss in the left ear that developed overnight. Audiometry confirms sensorineural hearing loss >30 dB across three contiguous frequencies. The structure marked **D** in the diagram indicates that MRI is essential to exclude vestibular schwannoma. Which of the following best explains why this imaging modality is a critical diagnostic step in all cases of sudden sensorineural hearing loss?