Recent research at a major medical center’s emergency department shows a sharp increase in CT angiography (CTA) usage for patients with headache or dizziness over five years, alongside a decrease in positive findings on these exams. This prompts concerns about the necessity and appropriateness of the 67% rise in CTA from 2017 to 2021, as reported in Internal and Emergency Medicine.

CTA, an advanced neurovascular imaging scan, swiftly detects damaged blood vessels, allowing prompt treatment for conditions like brain injuries, aneurysms, and strokes, potentially saving lives through the intravenous injection of a contrast dye to generate images of blood vessels and tissues. However, despite its life-saving potential, the American College of Radiology Appropriate Use Criteria indicates that CTA may not be clinically warranted in many cases of headache and dizziness, common complaints in the ED.

The study, conducted by researchers from Medically Engineered Solutions in Healthcare (MESH) Incubator and the Innovation in Operations Research Center (MESH IO) at Massachusetts General Brigham, in collaboration with the Harvey L. Neiman Health Policy Institute, analyzed ED admissions for headache and/or dizziness, along with associated CTA exams, using data from a level 1 trauma center evaluating approximately 110,000 ED patients annually.

The researchers found that CTA rates for headache and dizziness increased from 7.89% of ED visits in 2017 to 13.24% in 2021; a 67.4% increase over these five years.  On average, a given patient with headache and/or dizziness was 15% more likely to have a CTA in 2021 vs 2017.  To glean whether the increased use was driven by greater severity in ED patients, the researchers also evaluated the rate of positive findings on these CTAs.  They found that over the same period, the rate of positive findings dropped by 38%.

“Although the total number of CTA exams increased from 422 in 2017 to 662 in 2021, the number of patients with an abnormality detected actually dropped slightly from 71 to 69, accounting for the lower positivity rate,” says Marc Succi, MD, co-senior author, emergency radiologist, and executive director of the MESH Incubator.  “This finding suggests the increasing trend does not reflect increasing need, and that hospitals should take steps to ensure that imaging is appropriately used.”

Co-senior author Karen Buch, MD, a neuroradiologist at Massachusetts General Hospital shared concerns about observed disparities in the data: “Unfortunately, our results also revealed potential biases in the use of CTA for certain patient groups.  Specifically, patients with private insurance were more likely to have a CTA, whereas the likelihood of a CTA was less for Black compared to white patients.”

The published study was limited to a single medical center, so the researchers cannot say whether the results would be mirrored in other ED settings, nor whether the imaging was or was not appropriate. However, increasing utilization was expected.  

In the ED workflow, imaging orders are placed by the evaluating provider, be it a physician or, increasingly, a nurse practitioner or physician assistant. Recognizing the importance of accessible guidance on imaging appropriateness, the 2014 Protecting Access to Medicare Act (PAMA) mandates consultation of appropriate use criteria (AUC) via a qualified clinical decision support mechanism for advanced diagnostic imaging orders for Medicare patients. While the implementation of the PAMA AUC provisions is currently paused, many sites have adopted these programs to reduce unnecessary or low-value imaging.

“Clinical decision support can provide a seamless way to reduce the growing trends in advanced imaging in the ED without jeopardizing patient care or workflow efficiency. It also helps us to be good stewards of limited resources,” says John Jordan, MD, a neuroradiologist and chair of the ACR Commission on Neuroradiology. 

“While imaging offers ED providers assurance of an accurate diagnosis, it comes at a cost to patients—both in the expense of the imaging, as well as the exposure to radiation that may increase cancer risk,” he adds. “Weighing the benefits and risks is complicated, but worthwhile to ensure safe and cost-effective care.”