What is the accuracy of brain imaging for ED patients presenting with acute vertigo?

Question

What is the accuracy of brain imaging in detection of a central cause of dizziness for ED patients presenting with acute vertigo?

The Study

In March 2023, Academic Emergency Medicine (AEM) published a study that answered this question.

ED evaluation of dizziness is challenging and frequently involves neuroimaging to exclude a central cause (stroke, hemorrhage, tumor, etc). The authors note that misdiagnosis is frequent and costs associated with advanced imaging are high.

The study was a systematic review of literature from 2000-2021. 6309 publications were reviewed and 12 studies met criteria.

Inclusion criteria:

• ED study population of adult patients presenting with acute vertigo or dizziness with symptoms that started within the past 2 weeks without a known etiology
• The study assessed a neuroimaging test to evaluate for sensitivity and specificity of differentiating central from peripheral causes of vertigo/dizziness.

Exclusion criteria :

• Studies that did not report data allowing for calculation of sensitivity or specificity
• Studies published in languages other than English or Spanish
• Studies with a sample size of <10
• Narrative review, clinical guidelines or articles not available in full text.

What did they find?

• The criterion for a positive test was any central cause for dizziness (e.g., stroke, transient ischemic attack, intracerebral tumor, inflammatory lesions, and multiple sclerosis). The gold standard reference was delayed MRI (>48 hs).

Findings

• CT scan: sensitivity 28.5% and specificity 98.9% (771 patients in 6 studies)
• MRI: sensitivity 79.8% and specificity 98.8% (95% CI 96.2%–100%, high certainty); (943 patients in 5 studies)
• CTA: sensitivity 14.3% and specificity 97.7% (153 patients in 1 study)
• MRA: sensitivity 60.0% and specificity 92.9% (24 patients in 1 study)
• US: sensitivity 30%-53.6%, specificity 94.9%-100% (258 patients in 3 studies)

The authors also noted that “MRI with diffusion-weighted imaging can miss up to 20% of acute posterior circulation strokes when imaging is obtained <48 h from symptom onset”

Conclusion

Noncontrast CT has very low sensitivity and MRI will miss approximately one in five patients with stroke if imaging is obtained early after symptom onset. The evidence does not support neuroimaging as the only tool for ruling out stroke and other central causes in patients with acute dizziness or vertigo presenting to the ED.

These findings were used to create Guidelines for reasonable and appropriate care in the emergency department 3 (GRACE-3): Acute dizziness and vertigo in the emergency department, (Academic EM)

Read The Original Article

Shah VP, Oliveira J E Silva L, Farah W, Seisa M, Kara Balla A, Christensen A, Farah M, Hasan B, Bellolio F, Murad MH. Diagnostic accuracy of neuroimaging in emergency department patients with acute vertigo or dizziness: A systematic review and meta-analysis for the guidelines for reasonable and appropriate care in the emergency department. Acad Emerg Med. 2023 May;30(5):517-530. doi: 10.1111/acem.14561. Epub 2022 Aug 17. PMID: 35876220.