CT for headache: cost/benefit for subarachnoid hemorrhage.

Nationwide cost and benefit was estimated for performing computed tomography (CT) on headache patients in the hope of discovering a specific finding, subarachnoid hemorrhage. Case finding costs were estimated using a previously published survey of CT use at a university hospital where, of 258 headache patients scanned, two had subarachnoid bleeding due to ruptured aneurysms. The incidence and natural history of ruptured aneurysms from a large-scale clinical trial and the outcome of surgery from the recent literature were used in the calculations. The results ranged from a worst case calculation of $24,713/year and $543,688/person saved (ignoring all other diagnoses) to a best case calculation of $1,999/year and $43,975/person assuming that other positive diagnoses were of equal outcome to ruptured aneurysms. The analysis, using a technique recommended as a model for future determinations of this type, also demonstrated that a most important variable in determining costs is the case finding rate. If there is a need to improve the use of new diagnostic technologies, such as CT, concentration should be on the identification of the characteristics of high-yield patient groups.