What is the recommended imaging protocol for patients presenting with vertigo?

Imaging Protocol for Patients with Vertigo

The imaging approach for vertigo depends entirely on clinical presentation: no imaging is needed for brief episodic positional vertigo (BPPV) or acute persistent vertigo with normal neurologic exam and peripheral HINTS findings, while MRI head without IV contrast is the recommended modality for suspected central causes, particularly when neurologic examination is abnormal or HINTS suggests central pathology. 1

Clinical Classification Determines Imaging Strategy

The decision to image should be driven by specific clinical variants rather than the symptom of "vertigo" alone 1:

Variant 1: Brief Episodic Vertigo (Seconds to Minutes, Positional)

• No imaging is indicated when typical BPPV features are present with appropriate nystagmus on Dix-Hallpike maneuver and response to Epley maneuver 1
• Imaging should only be considered if atypical features exist, such as lack of nystagmus on provoking maneuvers or failure to respond to treatment 1

Variant 2: Acute Persistent Vertigo (Days to Weeks, Constant Symptoms)

With Normal Neurologic Examination:

• Imaging is not recommended when HINTS examination by a trained practitioner is consistent with peripheral vertigo (vestibular neuritis) 1
• MRI head without IV contrast may be helpful in high vascular risk patients (older age, hypertension, atrial fibrillation) even with normal neurologic exam, since 75-80% of posterior circulation infarcts present without focal deficits 2
• When a HINTS-trained practitioner is unavailable, MRI should be considered as the HINTS examination performed by non-experts is less reliable 2

Critical Pitfall: A normal neurologic examination does NOT exclude posterior circulation infarct 1, 2

Variant 3: Acute Persistent Vertigo with Abnormal Findings

MRI head without IV contrast is recommended when any of the following are present 1:

• Abnormal neurologic examination with focal deficits
• HINTS examination by trained specialist consistent with central vertigo (normal head impulse test, direction-changing nystagmus, or skew deviation)
• Combined neurological symptoms (strongest predictor with OR 16.72) 1
• Central oculomotor signs (OR 2.8) or focal abnormalities on examination (OR 3.3) 1

CT head without IV contrast may be appropriate as initial imaging before MRI in acute settings, though it has significantly lower sensitivity (28.5% vs 79.8% for MRI) 3:

• CT detects only 20-40% of causative pathology and misses many posterior circulation infarcts 2
• CT may be used for rapid screening when MRI is not immediately available 4
• Diagnostic yield of CT for isolated dizziness is extremely low (2.2%, with only 1.6% emergent findings) 1

Important Limitation: MRI with diffusion-weighted imaging (DWI) can be falsely negative in approximately 50% of small posterior fossa ischemic strokes within the first 48 hours 1. Some advocate for delayed MRI (3-7 days) if initial imaging was negative and clinical suspicion remains high 1

Variant 4: Chronic Recurrent Vertigo with Unilateral Hearing Loss or Tinnitus

Both MRI head and IAC without and with IV contrast AND CT temporal bone without IV contrast are useful 1:

• Primary purpose is exclusion of vestibular schwannoma, superior semicircular canal dehiscence, and other IAC masses rather than positive diagnosis of Meniere disease 1
• Most imaging facilities outside academic centers cannot perform specialized MRI protocols for endolymphatic hydrops evaluation 1

Variant 5: Chronic Recurrent Vertigo with Brainstem Neurologic Deficits

MRI head without IV contrast is useful for evaluation of posterior circulation infarcts 1

MRA or CTA of head and neck are useful for vascular evaluation 1

CT head without IV contrast may be appropriate as initial imaging 1

Key Performance Characteristics

MRI Diagnostic Yield:

• Overall yield in isolated dizziness: approximately 4% 1
• Changes diagnosis in up to 16% of cases, with acute findings in 8% 1
• Ischemic stroke is most common abnormality (nearly 70% of positive findings), with two-thirds in posterior circulation 1
• Sensitivity 79.8% (high certainty evidence), specificity 98.8% 3

CT Diagnostic Yield:

• Sensitivity only 28.5% (moderate certainty evidence), specificity 98.9% 3
• Detects significant pathology in <1% of isolated dizziness cases 2

Critical Clinical Point: The HINTS examination by trained practitioners has 100% sensitivity for posterior circulation stroke versus 46% for early MRI, making it superior to neuroimaging when performed correctly 2

Red Flags Mandating Immediate Imaging

Any of the following require urgent MRI evaluation 2:

• Focal neurological deficits
• Sudden hearing loss
• Inability to stand or walk
• Downbeating nystagmus or other central nystagmus patterns
• New severe headache accompanying dizziness
• Failure to respond to appropriate vestibular treatments

Common Pitfalls to Avoid

• Do not rely on patient descriptions of "spinning" versus "lightheadedness"—focus on timing, triggers, and associated symptoms instead 2
• Do not assume normal neurologic exam excludes stroke—most posterior circulation infarcts lack focal deficits 2
• Do not use CT as substitute for MRI when stroke is suspected—CT misses the majority of posterior circulation infarcts 2
• Do not order routine imaging for isolated dizziness without risk factors—yield is extremely low and most findings are incidental 2