Cost-effectiveness of computerized tomography and magnetic resonance imaging in dementia.

The benefits and costs of routinely using computerized tomography (CT) to diagnose surgically treatable causes of dementia compared to a more selective strategy were assessed, using a decision-analytic model, for hypothetical cohorts at 60, 70, and 80 years of age. The model was also used to project what the impact would be if magnetic resonance imaging (MRI) were to replace CT, assuming that MRI is a perfect test. Given plausible assumptions, routine CT could be expected to detect between 1 425 and 14 930 additional surgically treatable cases at an extra cost of between $0 and $49 million per 100 000 persons scanned. Replacing CT with MRI might yield an additional 70 to 150 cases of surgically treatable dementia, at an additional cost of $20-$30 million. Given current treatment limitations in dementia, it appears that, as a clinical tool, MRI will have little immediate health impact on this problem.