Indications for CT Scanning in Mild Traumatic Brain Injury: A Cost-Effectiveness Study

BACKGROUND: There is considerable uncertainty about the indications for cranial computed tomography (CT) scanning in patient with minor traumatic brain injury (TBI). This analysis involves an evidence-based comparison of several strategies for selecting patients for CT with regard to effectiveness and cost. METHODS: We performed a structured literature review of mild traumatic brain injury and constructed a cost-effectiveness model. The model estimated the impact of missed intracranial lesions on longevity, quality of life and costs. Using a 20-year-old patient for primary analysis, we compared the following strategies to screen for the need to perform a CT scan: observation in the emergency department or hospital floor, skull radiography, Selective CT based on the presence of additional risk factors and scanning all. RESULTS: Outcome measures for each strategy included average years of life, quality of life and costs. Selective CT and the CT All policy performed significantly better than the alternatives with respect to outcome. They were also less expensive in terms of total direct health care costs, although the differences did not reach statistical significance. The model yielded similar, but smaller, differences between the selective imaging and other strategies when run for older patients. CONCLUSIONS: Although the incidence of intracranial lesions, especially those that require surgery, is low in mild TBI, the consequences of delayed diagnosis are forbidding. Adverse outcome of an intracranial hematoma is so costly that it more than balances the expense of CT scans. In our cost-effectiveness model, the liberal use of CT scanning in mild TBI appears justified.