BACKGROUND. Underlying stroke is often misdiagnosed in patients presenting with dizziness. Although such patients are usually ineligible for acute stroke treatment, accurate diagnosis may still improve outcomes through selection of patients for secondary prevention measures. OBJECTIVE. The purpose of our study was to investigate the cost-effectiveness of differing neuroimaging approaches in the evaluation of patients presenting to the emergency department (ED) with dizziness who are not candidates for acute intervention. METHODS. A Markov decision-analytic model was constructed from a health care system perspective for the evaluation of a patient presenting to the ED with dizziness. Four diagnostic strategies were compared: noncontrast head CT, head and neck CTA, conventional brain MRI, and specialized brain MRI (including multiplanar high-resolution DWI). Differing long-term costs and outcomes related to stroke detection and secondary prevention measures were compared. Cost-effectiveness was calculated in terms of lifetime expenditures in 2022 U.S. dollars for each quality-adjusted life year (QALY); deterministic and probabilistic sensitivity analyses were performed. RESULTS. Specialized MRI resulted in the highest QALYs and was the most cost-effective strategy with US$13,477 greater cost and 0.48 greater QALYs compared with noncontrast head CT. Conventional MRI had the next-highest health benefit, although was dominated by extension with incremental cost of US$6757 and 0.25 QALY; CTA was also dominated by extension, with incremental cost of US$3952 for 0.13 QALY. Non-contrast CT alone had the lowest utility among the four imaging choices. In the deterministic sensitivity analyses, specialized MRI remained the most cost-effective strategy. Conventional MRI was more cost-effective than CTA across a wide range of model parameters, with incremental cost-effectiveness remaining less than US$30,000/QALY. Probabilistic sensitivity analysis yielded similar results as found in the base-case analysis, with specialized MRI being more cost-effective than conventional MRI, which in turn was more cost-effective than CTA. CONCLUSION. The use of MRI in patients presenting to the ED with dizziness improves stroke detection and selection for subsequent preventive measures. MRI-based evaluation leads to lower long-term costs and higher cumulative QALYs. CLINICAL IMPACT. MRI, incorporating specialized protocols when available, is the preferred approach for evaluation of patients presenting to the ED with dizziness, to establish a stroke diagnosis and to select patients for secondary prevention measures.
Keywords: CTA; MRI; cost-effectiveness; dizziness; stroke.