Cranial computed tomography in the emergency evaluation of adult patients without a recent history of head trauma: a prospective analysis

Objectives

To examine the pattern of nontrauma cranial CT use in an urban ED, to identify the rate of significant CT abnormalities in headache, and to develop criteria for restricting the ordering of CT scans.

Methods

A prospective, observational study of a case series of adults who underwent cranial CT scanning for non-traumatic headache was performed at the ED of an urban teaching hospital with an annual census of 55 000. Clinically significant CT scans were defined as: 1) acute stroke, 2) CNS malignancy, 3) acute hydrocephalus, 4) intracranial bleeding or 5) intracranial infection. X2 recursive partioning was used to derive a decision rule to restrict ordering of CT scans.

Results

Only 12 (4%) of 291 CT scans revealed clinically significant abnormalities. The presence of headache with vomiting was 100% sensitive (95%CI: 74–100%) and 49% specific (95%CI: 43–56%) in detecting clinically significant CT scans. This set of features had positive and negative values of 8%(95%CI: 4–13%) and 100% (95% CI: 97–100%), respectively.

Conclusion

Clinically significant CT abnormalities were uncommon in the headache patients population, suggesting that current criteria for ordering nontrauma cranial CT scans may be too liberal. In this study, a set of clinical criteria was derived that may be useful at separating patients into high- and low-risk categories for clinically significant cranial CT abnormalities. Before these results are applied clinically, these criteria should be validated in larger, prospective studies.