Weighing Use of CT Scans in Non-Traumatic Headaches at EDs

December 13th, 2016

MADISON, WI – Determining when and how often to use CT scans for non-traumatic headaches can be difficult for emergency physicians. A new study offers more information to help make that decision.

The retrospective observational study published in the American Journal of Roentgenology reports that patients who underwent CT examination for atraumatic headache in an initial emergency department (ED) visit were less likely to return to the ED within 30 days.

Study authors are quick to point out, however, that they are not pushing greater use of the expensive technology.

"I think it would be easy to misinterpret this study as a call for increasing the practice of ordering CT scans for atraumatic headache," said lead study author Brian W. Patterson, MD, an emergency physician with the University of Wisconsin School of Medicine and Public Health. "Our findings do not support such a recommendation. Rather, we are calling attention to the downstream effects of these scans, and suggesting that future attempts to define appropriateness of imaging within the ED will need to account for their potential to lessen future care utilization."

The research was prompted by the growing trend of criticism associated with the increased rate of CT imaging in EDs, according to the study, which points out, "A variety of efforts have been aimed to reduce CT use within the ED given the costs and risks associated with ionizing radiation. Specifically, the use of CT of the brain for patients with atraumatic headache has been identified as potentially inefficient, as evidenced by wide variation in ordering rates between ED providers and low diagnostic yields."

The study was performed at an academic urban ED, Northwestern Memorial Hospital in Chicago, with more than 85,000 annual visits. It focused on 922 adult patients with a chief complaint of headache from January through December 2010 who were discharged after evaluation.

Results indicate that 139 (15.1%) patients revisited within 30 days, for a return rate that was 11.2% among patients who underwent CT at their initial visit and 21.1% among those who did not. An adjusted analysis controlling for age, race, sex, insurance status, triage vital signs, laboratory values, and triage pain level put the odds ratio for revisitation given CT performance at 0.49.

Researchers suggested several possible explanations for the study findings, including that CT results provided reassurance to patients, thereby preventing return ED visits. They also posit that the testing could allow outpatient providers, particularly primary care clinicians, to better focus on and manage the symptoms of an acute headache because emergent pathology has been ruled out.

"After adjustment for clinical factors, we found that patients who underwent a brain CT examination for atraumatic headache at an initial ED visit were less likely to return to the ED within 30 days,” study authors conclude. “Future appropriate use quality metrics regarding ED imaging use may need to incorporate downstream healthcare use."