Standard contrast protocols may be 'overdosing' women with the imaging agent
New research is calling into question the amount of iodinated contrast given to women during thoracoabdominal CT exams, revealing that females attenuate “significantly more” contrast in their vessels and organs compared to men.
Published in European Radiology, the study compares contrast attenuation in the blood and solid organs of both men and women and how other factors, like BMI, age, height and blood volume, affect the amount of contrast within a person’s system following injection. Authors of the new paper suggested that their findings highlight concerns with relying on weight-based dosing protocols, as these may be adversely affecting women.
“Despite the great benefits of contrast-enhanced imaging, the use of iodinated CM...must be carefully considered because of various factors. Some of the most important risks include allergic reactions, contrast-induced nephropathy and inducible thyroid dysfunction,” Thomas Kroencke, with the Department of Diagnostic and Interventional Radiology at University Hospital Augsburg in Germany, and colleagues explained. “Historically, these risks were thought to be sex-unspecific, affecting men and women equally; however, recent studies suggest that women are more likely to experience adverse effects from CM than men.”
For the study, researchers retrospectively analyzed 274 thoracoabdominal CT scans conducted between August 2021 and January 2022. Each patient received roughly the same contrast dose—100 or 120-mL. Iodinated contrast in the liver, portal vein, spleen, left atrium, left ventricle, pulmonary trunk, and ascending and descending aorta were measured for each patient, while a subanalysis evaluated the impact of sex, age, BMI, height, weight, and blood volume on these measurements.
When given the same dose, contrast attenuation in the blood and organs of women was found to be markedly higher than in men. Even after adjusting for height, weight and other variables, sex was determined to play a significant role in how much contrast was present in patients’ blood and organs, with women showing higher parenchymal and vascular iodine contrast.
Based on these findings, the authors suggested that adjusting contrast dosing based on blood volume (calculated via the Nadler method) could offer the safest and most effective approach for scanning women who require contrast-enhanced exams.
“We suggest that the amount of CM should be sex-adapted in delayed CT scans,” the authors wrote. “In this study, the iodine contrast in organs and the blood pool was not significantly influenced by sex when correcting for blood volume. Only the iodine contrast of the spleen sex remained significant after correction for BV, which may be due to its often inhomogeneous enhancement and the resulting difficulty in obtaining valid measurements.”
Not only could this method reduce risks related to contrast exposure, it also could optimize the use of resources and reduce healthcare costs, the authors signaled.
The study abstract is available here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.