The cost-effectiveness of magnetic resonance imaging for patients with equivocal neurological symptoms.

OBJECTIVE: To determine the incremental cost-effectiveness of magnetic resonance imaging (MRI) and computed tomography (CT) in young adults presenting with equivocal neurological signs and symptoms. DESIGNS AND METHODS: A decision analysis of long-term survival using accuracy data from a diagnostic technology assessment of MRI and CT in patients with suspected multiple sclerosis, information from the medical literature, and clinical assumptions. MAIN RESULTS: In the baseline analysis, at 30% likelihood of an underlying neurologic disease, MRI use has an incremental cost of $101,670 for each additional quality-adjusted life-year saved compared with $20,290 for CT use. As the probability of disease increases, further MRI use becomes a cost-effective alternative costing $30,000 for each quality-adjusted life-year saved. If a negative MRI result provides reassurance, the incremental costs of immediate MRI use decreases and falls below $25,000 for each quality-adjusted life-year saved no matter the likelihood of disease. CONCLUSIONS: For most individuals with neurological symptoms or signs, CT imaging is cost-effective while MR imaging is not. The cost-effectiveness of MRI use, however, improves as the likelihood of an underlying neurological disease increases. For selected patients who highly value diagnostic information, MRI is a reasonable and cost-effective use of medical resources when even the likelihood of disease is quite low (5%).