What is the preferred imaging modality, Computed Tomography (CT) scan or Magnetic Resonance Imaging (MRI), for a patient presenting with vertigo and hand numbness?

From the Guidelines

MRI is the preferred imaging modality for a patient presenting with vertigo and hand numbness. This combination of symptoms suggests a potential neurological issue, possibly involving the brainstem, cerebellum, or cervical spine, which MRI can visualize with superior soft tissue contrast 1. The presence of hand numbness alongside vertigo increases the likelihood of a central cause, such as a stroke, multiple sclerosis, or a structural lesion in the posterior fossa or cervical spine, all of which are better visualized with MRI.

According to the American College of Radiology Appropriateness Criteria, the diagnostic yield of MRI increases to 12% when associated neurologic findings are present, such as hand numbness 1. While CT scans are useful in emergency settings for detecting acute hemorrhage or skull fractures, they have limited sensitivity for posterior fossa lesions and spinal cord abnormalities, making MRI a more comprehensive choice for evaluating vertigo with neurological symptoms like hand numbness.

Key points to consider include:

• MRI provides superior soft tissue contrast for visualizing brainstem, cerebellum, and cervical spine pathologies.
• The presence of hand numbness alongside vertigo suggests a potential central cause that is better evaluated with MRI.
• MRI has a higher diagnostic yield than CT when neurologic symptoms are present, as indicated by the increased positivity rate of diffusion-weighted imaging (DWI) MRI from 4% in isolated dizziness to 12% when associated neurologic findings are present 1.
• CT scans are more appropriate for suspected acute hemorrhage, skull fracture, or when MRI is contraindicated due to certain implanted devices or severe claustrophobia.

Given the clinical presentation of vertigo and hand numbness, an MRI with contrast (if not contraindicated) is recommended for a comprehensive evaluation of potential neurological causes, allowing for the visualization of both brain and cervical spine structures that could explain this symptom combination 1.

From the Research

Imaging Modalities for Vertigo and Hand Numbness

• The choice between Computed Tomography (CT) scan and Magnetic Resonance Imaging (MRI) for a patient presenting with vertigo and hand numbness depends on the clinical suspicion of the underlying cause 2, 3, 4.
• For patients with vertigo, the diagnostic yield of head CT is low (2.2%) 4, and it is often not helpful in identifying the cause of vertigo 5.
• MRI is more useful in detecting infarctions in patients with vascular dizziness/vertigo, especially in the posterior-circulation territories 6.
• A study found that MRI of the inner ear and cerebellopontine angle presented the most significant findings (17.7%) in patients with vertigo and dizziness 2.
• The HINTS (head-impulse, nystagmus, test of skew) examination can help distinguish peripheral from central etiologies of vertigo, and it is recommended to use this examination to guide the selection of imaging tests 3.

Specific Considerations

• For benign paroxysmal positional vertigo (BPPV), imaging is not usually necessary, and the canalith repositioning procedure (e.g., Epley maneuver) can be used for treatment 5.
• For patients with stroke, imaging is crucial, and CT or MRI can be used to diagnose the condition 3.
• The cost-utility analysis of CT and MRI in the study of vertigo and dizziness found that the cost for a positive test was 1,576 euros, and a large number of head CT and MRI are made in patients with vertigo and dizziness 2.

Imaging Recommendations

• For patients with vertigo and hand numbness, MRI may be a better choice than CT scan, especially if there is a suspicion of vascular dizziness/vertigo or posterior-circulation territories infarction 2, 4, 6.
• However, the final decision on the imaging modality should be based on the clinical evaluation and suspicion of the underlying cause 5, 3.