What is the role of Computed Tomography (CT) scan in diagnosing vertigo?

From the Guidelines

CT scans are not routinely recommended as the first-line imaging test for patients with vertigo unless there are specific concerning features, such as severe headache, focal neurological deficits, altered mental status, or recent head trauma, as the diagnostic yield of CT remains very low (<1%) 1.

Key Considerations

• The positivity rate of head CT in the emergency department for patients presenting with vertigo is approximately 2%, with the most common positive findings including ischemic stroke, neoplasm, and hemorrhage 1.
• MRI is generally preferred for evaluating vertigo because it provides better visualization of the posterior fossa, inner ear structures, and brainstem 1.
• In patients with acute persistent vertigo and an abnormal neurologic examination or HINTS examination consistent with central vertigo, posterior circulation infarct is suspected, and MRI head without IV contrast is recommended 1.
• A non-contrast CT scan may be appropriate in emergency settings to quickly rule out life-threatening conditions like hemorrhage, large stroke, or mass effect 1.

Diagnostic Approach

• The diagnostic approach to vertigo should be guided by the patient's history, physical examination findings, and associated symptoms rather than reflexively ordering imaging studies 1.
• Various bedside tests, such as the HINTS examination, have been developed to distinguish acute vestibular syndrome (AVS) of benign cause from posterior circulation infarct 1.
• For patients with persistent or recurrent vertigo, an MRI with contrast is more sensitive for detecting small infarcts, demyelinating lesions, or acoustic neuromas 1.

Radiation Exposure

• The radiation exposure from CT scans should be considered, especially in younger patients or those requiring repeated imaging 1.
• CT temporal bone studies (with thin cuts through the temporal bone) may be useful in cases of trauma-related vertigo or to evaluate bony abnormalities of the inner ear, but should be used judiciously due to radiation exposure concerns 1.

From the Research

CT Scan in Vertigo

• The use of CT scans in diagnosing vertigo is a common practice, especially in emergency departments 2.
• A study published in the American Journal of Otolaryngology found that 42.0% of patients with benign paroxysmal positional vertigo (BPPV) received imaging, with the most common modality being plain CT Head (54.2%) 2.
• However, the study also noted that CT head was the initial imaging of choice in 44.7% of cases, and CT/CTA in 42.6%, despite the limitations of computed tomography in diagnosing posterior circulation strokes 2.
• Another study published in the Laryngoscope Investigative Otolaryngology found that BPPV is typically diagnosed through clinical history and diagnostic maneuvers, and does not require additional ancillary testing such as CT scans 3.
• The use of CT scans in vertigo diagnosis has been criticized for being overly utilized, and the HINTS exam has been proposed as a bedside test to rule out stroke in patients presenting with acute vestibular syndrome (AVS) 4.

Diagnostic Procedures for Vertigo

• Current diagnostic procedures for vertigo include the HINTS exam, video head impulse test, and vestibular evoked myogenic potentials 5.
• A systematic review and meta-analysis published in Academic Emergency Medicine found that the HINTS examination, when performed by neurologists, had a high sensitivity and specificity for ruling out a central cause of vertigo, but its accuracy when performed by emergency physicians was lower 4.
• The study suggested that the HINTS examination, when used in isolation by emergency physicians, may not be sufficiently accurate to rule out a stroke in patients presenting with AVS 4.

Treatment of Vertigo

• A study published in The Journal of Emergency Medicine found that diazepam and meclizine were equally effective in treating patients with peripheral vertigo in the emergency department 6.
• The study suggested that the choice of treatment for vertigo may depend on the underlying cause and the patient's symptoms, rather than the use of CT scans or other diagnostic tests 6.