How to Conserve CT Contrast Media During a Shortage

NEW YORK (Reuters Health) – The amount of intravenous contrast media used for CT scans could be reduced by about 80% by using a combination of dose-reduction strategies, researchers report.

In April of this year, a global shortage of iodinated contrast media occurred due in large part to supply-chain issues fueled by the COVID-19 pandemic. The shortage is expected to continue into at least this summer and will affect millions of CT exams.

In a modeling study published in JAMA, Dr. Michael Davenport of Michigan Medicine in Ann Arbor and colleagues identified five ways to conserve iodinated contrast media for CT scans during the shortage:

1. Weight-based dosing for non-neurological CT exams.

2. Reducing kV and contrast-media dose if patient weight is less than 176 lbs (80 kg).

3. Performing non-contrast CT exams if the effect on accuracy is moderate (especially for nonvascular studies).

4. A combination of 1 and 2.

5. A combination of 1, 2, and 3.

They scaled the results (using data on age, weight, indication and contrast use) to a hypothetical population of one million CT scans in adults and calculated reductions in total contrast use from baseline.

For the base case, they estimated that 47.1 million mL of contrast would be used for the one million CT scans. The base case assumed the availability of multi-use vials.

The model estimated that weight-based dosing would reduce use by 12% (to 41.6 million mL) and that reducing tube voltage and contrast dose would reduce use by 25% (to 35.4 million mL).

The biggest reduction (78%, to 10.5 million mL) would involve performing unenhanced CT instead of contrast-enhanced CT when moderate reduction in diagnostic accuracy is acceptable.

Combining all three approaches would yield an estimated 83% reduction in use (to 7.8 million mL).

The base case estimate for single-use 100-mL vials would be 77.7 million mL versus an estimated 47.1 million mL for multi-use vials, but the relative benefits of the different reduction strategies are similar, the researchers report.

“Adoption of some of the dose-reduction strategies beyond the current shortage could mitigate supply chain risk and remove waste,” Dr. Davenport and colleagues say.

They caution that they did not model the potential reduction in diagnostic accuracy or potential harm to patients from withholding contrast.

The study had no specific funding. Dr. Davenport is vice chair of the commission on quality and safety and former chair of the committee on drugs and contrast media for the American College of Radiology and is on the board of directors for the Society of Advanced Body Imaging.

SOURCE: JAMA, online June 9, 2022.

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