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 u rban ED, to identify the rate of significant CT abnormalities in this setting, and to develop criteria for restricting the ordering of CT sc ans. Methods: A prospective, observational study of a case series of a dults who underwent cranial CT scanning for nontraumatic cases was per formed at the EDs of an urban teaching hospital and an affiliated comm unity hospital with a combined annual census of 110,000. Clinically si gnificant CT scans were defined as: 1) acute stroke, 2) CNS malignancy , 3) acute hydrocephalus, 4) intracranial bleeding, or 5) intracranial infection. X-2 recursive partitioning was used to derive a decision r ule to restrict ordering of CT scans. Results: Only 61 (8%) of 806 CT scans revealed clinically significant abnormalities. The presence of a ny of the following: age greater than or equal to 60 years, focal neur ologic deficit, headache with vomiting, or altered mental status, was 100% sensitive (95% CI: 94-100%) and 31% specific (95% CI: 28-33%) in detecting clinically significant CT scans. This set of features had po sitive and negative predictive values of 11% (95% CI: 8-13%) and 100% (95% CI: 98-100%), respectively. If these criteria had been used to re strict cranial CT use, 229 fewer patients (28%) would have had CT scan s obtained and no clinically significant abnormalities would have been missed. Conclusion: Clinically significant CT abnormalities were unco mmon in this study population, suggesting that current criteria for or dering 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 significan t cranial CT abnormalities. Before these results are applied clinicall y, these criteria should be validated in larger, prospective studies.