Cost-effectiveness of functional imaging tests in the diagnosis of Alzheimer disease.
OBJECTIVE
To evaluate the cost-effectiveness of functional neuroimaging in the work-up of patients at specialized Alzheimer disease clinics.


METHODS
A decision model was used to calculate costs and benefits (in quality-adjusted life-years [QALYs]) that accrued to hypothetical cohorts of patients at presentation to an Alzheimer disease center. Sensitivity analysis was performed to examine the effects of diagnostic test characteristics, therapeutic efficacy, disease severity, and costs on cost-effectiveness.


RESULTS
The incremental cost-effectiveness ratio of dynamic susceptibility contrast material-enhanced magnetic resonance (MR) imaging was $479,500 per QALY (compared with the usual diagnostic work-up), while visual or quantitative single photon emission computed tomography (SPECT) was dominated (higher costs, lower effectiveness) by the usual diagnostic work-up. These results depend critically on the sensitivity and specificity of the standard diagnostic work-up, the effectiveness of drug treatment, and the disease severity. Varying these parameters resulted in estimates of incremental cost-effectiveness for dynamic susceptibility contrast-enhanced MR imaging of $24,680 to $8.6 million per QALY. SPECT either was dominated by the usual diagnostic work-up or had cost-effectiveness ratios of $180,200 to $6 million per QALY.


CONCLUSIONS
The addition of functional neuroimaging to the usual diagnostic regimen at Alzheimer disease clinics is not cost-effective given the effectiveness of currently available therapies.
McMahon
P M
PM
Department of Radiology, Decision Analysis and Technology Assessment Group, the Computer-Assisted Diagnostics Laboratory, Massachusetts General Hospital, Zero Emerson Pl, Ste 2H, Boston, MA 02114, USA.
Araki
S S
SS
Neumann
P J
PJ
Harris
G J
GJ
Gazelle
G S
GS
D000544:Alzheimer Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy; D003287:Contrast Media; D003362:Cost-Benefit Analysis; D003663:Decision Trees; D000077265:Donepezil; D017048:Health Care Costs; D006801:Humans; D007189:Indans / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging / Q000191:economics*; D008390:Markov Chains; D018803:Models, Economic; D018697:Nootropic Agents / Q000627:therapeutic use; D010880:Piperidines / Q000627:therapeutic use; D019057:Quality-Adjusted Life Years; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000191:economics*
D003287:Contrast Media; D007189:Indans; D018697:Nootropic Agents; D010880:Piperidines; D000077265:Donepezil