Reducing iodinated contrast volume by almost 40% in head and neck CT angiography (CTA) maintains or even improves diagnostic image quality -- and generates meaningful cost savings, researchers have reported.
Their findings show that "standardized contrast dose reduction for [head-neck] CTA is feasible, sustainable, and does not compromise imaging," wrote a team led by Jocelyn Wu, MD, of the University of Utah in Salt Lake City. The study was published April 30 in the Journal of the American College of Radiology.
Head and neck CTA use has increased dramatically over the past 20 years, with most exams ordered in the emergency department for patients presenting with stroke symptoms, trauma, headache, dizziness, and altered mental status, the group explained. This increase has prompted an effort to reduce contrast use – made more possible due to advances in CT technology.
But contrast dosing for head and neck CTA has remained "largely unchanged," the team wrote. It conducted a study that explored implementation and outcomes of a standardized dose reduction protocol for head and neck CTA.
The investigators included in the study a total of 3,604 inpatient, outpatient, and emergency department patients who underwent head and/or neck CTA between July 2024 and February 2025. Patients were divided into baseline, phase one, and phase two groups by CTA head and CTA neck exams. Starting from a baseline dose of 100 mL of Isovue-370, the team implemented two sequential reductions: first to 70 mL (phase one, six weeks after baseline), then to 60 mL (phase two, eight weeks after baseline).
The group randomly selected 65 CTA head and 65 CTA neck exams from each of the study cohorts, and three readers rated the images' diagnostic quality using a five-point Likert scale. They also calculated contrast-to-noise ratio and tracked demographic and exam variables (CTDI [CT dose index], DLP [dose length product], age, sex, race, weight, BMI, history of heart failure, and exam timing). The study's primary outcome was image quality, while its secondary outcome was any cost savings that arose from contrast dose reduction.
The researchers reported the following:
- Mean contrast dose decreased from 103 mL at baseline to 73 mL in phase one and 64 mL in phase two (both, p < 0.05).
- Vessel quality ratings were similar to slightly improved after dose reduction.
- Statistically significant improvements occurred in the left V1 vertebral artery from baseline to 70 mL (3.6 versus 3.8 on the Likert scale; p < 0.05) and at the carotid bulbs comparing baseline to 60 mL (right: 4.3 versus 4.5; left: 4.3 versus 4.5; p < 0.05).
- There was no statistically significant difference in mean vessel opacification or CNR across phases.
From a cost standpoint, a 39-mL reduction saved $19.89 per exam, according to the authors. Projected annually across 5,000 examinations, this represents a cost reduction from roughly $131,000 to $82,000 -- a 38% decrease, they explained.
They also noted that broader health system adoption of this lower-use CTA contrast dose protocol could reduce iodinated contrast consumption by approximately "100,000 mL annually (assuming 5,000 annual exams, halved as the same dose is used for both head and neck)," with corresponding reductions in vial waste and environmental contamination, which could "mitigate downstream ecological effects and reduce the environmental burdens associated with iodine production and distribution."
The authors noted that equivalent reductions may not be achievable on older CT platforms, and stressed that image quality varies with body habitus and cardiac comorbidities. But the findings are promising, they wrote.
"Further reduction may be possible with emerging technologies such as dual-energy CT, photon counting CT, and advanced bolus-tracking techniques," they concluded.
Access the full study here.
