Cost-effectiveness of functional imaging tests in the diagnosis of Alzheimer disease

PURPOSE: To evaluate the cost-effectiveness of functional neuroimaging in t he work-up of patients at specialized Alzheimer disease clinics. MATERIALS AND METHODS: A decision model was used to calculate costs and ben efits (in quality-adjusted life-years [QALYs]) that accrued to hypothetical cohorts of patients at presentation to an Alzheimer disease center. Sensit ivity analysis was performed to examine the effects of diagnostic test char acteristics, therapeutic efficacy, disease severity, and costs on cost-effe ctiveness. RESULTS: The incremental cost-effectiveness ratio of dynamic susceptibility contrast material-enhanced magnetic resonance (MR) imaging was $479,500 pe r QALY (compared with the usual diagnostic work-up), while visual or quanti tative single photon emission computed tomography (SPECT) ws dominated (hig her cost, lower effectiveness) by the usual diagnostic work-up. These resul ts depend critically on the sensitivity and specificity of the standard dia gnostic work-up, the effectiveness of drug treatment, and the disease sever ity. Varying these parameters resulted in estimates of incremental cost-eff ectiveness for dynamic susceptibility contrast-enhanced MR imaging of $24,6 80 to $8.6 million per QALY. SPECT either was dominated by the usual diagno stic work-up or had cost-effectiveness ratios of $180,200 to $6 million per QALY. CONCLUSION: The addition of functional neuroimaging to the usual diagnostic regimen at Alzheimer disease clinics is not cost-effective given the effec tiveness of currently available therapies.