Head computed tomography utilization and intracranial hemorrhage rates.

Utilization of computed tomography scans (CTs) has increased dramatically in emergency departments in the USA. This study aimed to retrospectively determine the yield of CTs among all patients that received a CT of the head from 2001 to 2007, which is adjusted for patient volume. For secondary endpoints, we examined the yield of CT of the head for the following hemorrhages: (1) intracerebral, (2) subarachnoid, (3) subdural, and (4) epidural. In 2001, 3.3 head CTs were performed per 100 patients seen. This increased by 60 % to 5.2 per 100 in 2007 (p = 0.005, R (2) = 0.82). This correlated with a nonsignificant decrease in the rate of intracranial hemorrhage found by CT from 3.6 per 100 CTs in 2001 (95 % confidence interval (CI) = 2.7-4.5) to 3.0 per 100 in 2007 (95 % CI = 2.5-3.6). There were no significant differences in "positive" rates for each subgroup of intracranial hemorrhage. Our study found that the utilization of head CTs increased dramatically, but there was a corresponding increase in the number of positive findings so that the overall yield of head CTs from 2001 to 2007 remained relatively constant.