When do we consider brain imaging in patients presenting with vertigo?

Brain Imaging in Patients Presenting with Vertigo

Brain imaging is not necessary for patients with typical benign paroxysmal positional vertigo (BPPV) with positive Dix-Hallpike testing, but should be performed when there are features suggesting a central cause, including abnormal neurological examination, atypical nystagmus patterns, or a negative HINTS examination. 1

Key Indications for Brain Imaging

Acute Vestibular Syndrome (AVS)

• Brain imaging is indicated in patients with acute persistent vertigo when:
  • Neurological examination reveals focal deficits 1
  • HINTS examination suggests a central cause (normal head impulse test, direction-changing nystagmus, or skew deviation) 2
  • Symptoms are unresponsive to emergency department treatment, especially in patients with history of hypertension or coronary artery disease 3
• Despite normal neurological examination, up to 11% of patients with acute persistent vertigo may have acute brain infarcts, with posterior circulation stroke being the most concerning diagnosis to exclude 1

Episodic Vertigo

• Imaging is generally unnecessary for typical BPPV with positive Dix-Hallpike testing 1
• Consider brain imaging when:
  • Dix-Hallpike testing is negative or shows atypical nystagmus patterns 1
  • Patient is unresponsive to repositioning maneuvers 1
  • There is short-term recurrence of symptoms despite treatment 1
  • Patient is elderly or has vascular risk factors 1
  • Post-traumatic onset of symptoms 1

Chronic or Recurrent Vertigo

• Brain imaging is indicated when:
  • Associated with hearing loss or tinnitus to evaluate for conditions like acoustic neuroma 4
  • Associated with brainstem neurological deficits to evaluate for vertebrobasilar insufficiency 5
  • Positional vertigo with purely vertical nystagmus (upbeating or downbeating), which may suggest a central lesion near the fourth ventricle 5

Imaging Modality Selection

MRI

• MRI is the preferred modality for evaluating vertigo due to superior soft tissue resolution 1
• MRI with diffusion-weighted imaging (DWI) has higher sensitivity (79.8%) compared to CT (28.5%) for detecting central causes of vertigo 6
• MRI can better characterize masses, inflammatory processes, demyelinating disease, and small infarcts 1
• Consider adding contrast when suspecting tumors, inflammatory, infectious, or demyelinating processes 1

CT

• CT may be used as an initial rapid screening tool when MRI is not immediately available 1
• CT detected acute brain lesions in 6% of cases compared to 11% with MRI in patients with central positional paroxysmal vertigo (CPPV) 1
• CT has limited sensitivity (28.5%) but high specificity (98.9%) for central causes of vertigo 6

Clinical Pearls and Pitfalls

• The HINTS examination, when performed by properly trained clinicians, can be more sensitive than early MRI for detecting stroke in acute vestibular syndrome 2
• Cerebellar infarction can sometimes present with isolated vertigo and imbalance without other neurological signs, making it difficult to distinguish from peripheral causes 5
• Early MRI may miss approximately 20% of strokes if performed too soon after symptom onset 6
• Vertebrobasilar insufficiency typically causes vertigo lasting minutes, whereas peripheral causes typically last hours 5
• Neuroimaging alone should not be relied upon to rule out stroke and other central causes in patients with acute dizziness or vertigo 6