What is the recommended imaging for an adult patient with persistent vertigo that worsens with Valsalva (Valsalva maneuver) and has not improved with Epley's (canalith repositioning procedure) maneuver?

Recommended Imaging for Persistent Vertigo with Valsalva Provocation Unresponsive to Epley Maneuver

Order MRI head without IV contrast immediately, as this presentation represents atypical BPPV that warrants imaging to exclude central causes including posterior circulation stroke, mass lesions, or superior semicircular canal dehiscence. 1

Clinical Reasoning

Your patient's presentation has two critical red flags that mandate imaging:

• Lack of response to Epley maneuver - The ACR Appropriateness Criteria explicitly state that imaging is indicated in brief episodic vertigo when there is "lack of response to treatment maneuvers (eg, Epley)" 1

• Worsening with Valsalva - This specific trigger suggests superior semicircular canal dehiscence or perilymphatic fistula, conditions that require structural imaging to diagnose 1

Specific Imaging Recommendation

First-Line: MRI Head Without IV Contrast

MRI head without IV contrast is the recommended initial study because: 1

• It detects acute ischemic stroke (the most common serious pathology) in approximately 70% of positive cases, with two-thirds located in the posterior circulation 1
• It has superior soft tissue resolution compared to CT for detecting central causes 1
• The diagnostic yield is approximately 4% in isolated dizziness, but increases to 11% in patients with atypical features like treatment failure 1

Alternative: CT Temporal Bone Without IV Contrast

Consider adding CT temporal bone without IV contrast specifically because: 1

• Superior semicircular canal dehiscence (suggested by Valsalva provocation) is readily diagnosed on CT temporal bone 1
• This structural abnormality cannot be detected on standard brain MRI 1

Why Not CT Head?

Avoid CT head as the sole imaging modality - it has only 20-40% sensitivity for detecting causative pathology in vertigo and misses most posterior circulation infarcts 2. CT detected acute brain lesions in only 6% of atypical BPPV cases compared to 11% with MRI 1

Clinical Context and Risk Stratification

The combination of treatment failure and Valsalva provocation places your patient in a higher-risk category: 1

• Central causes masquerading as BPPV occur in approximately 3% of treatment failures 3
• Risk factors that increase likelihood of central pathology include: older age, hypertension, atrial fibrillation, and vascular risk factors 1
• Even with normal neurologic examination, up to 75-80% of posterior circulation strokes causing vertigo may lack focal neurologic deficits initially 3, 4

Critical Pitfalls to Avoid

• Do not assume this is simply refractory BPPV - the Valsalva provocation is atypical for classic BPPV and suggests alternative pathology 1
• Do not delay imaging pending additional repositioning attempts - treatment failure is itself an indication for imaging per ACR guidelines 1
• Do not rely on normal neurologic examination to exclude central causes - normal examination does not exclude posterior circulation infarct 1, 4

Additional Diagnostic Considerations

If MRI head and CT temporal bone are both negative, consider: 1

• MRI head and internal auditory canal (IAC) without and with IV contrast - useful for detecting vestibular schwannoma or other IAC masses that can present with atypical vertigo 1
• MRA or CTA head and neck - if vascular insufficiency is suspected based on risk factors, though there was disagreement in guidelines about this as initial imaging 1

The key principle is that atypical features (Valsalva provocation) plus treatment failure (unresponsive to Epley) = mandatory imaging to avoid missing serious central pathology. 1