Perspective from Pamela J. Lund, MD
Disclosures: Smith-Bindman reports being a co-founder of Alara Imaging.
June 22, 2022
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Combined dose-reduction strategies may reduce contrast use by 80%

Perspective from Pamela J. Lund, MD
Disclosures: Smith-Bindman reports being a co-founder of Alara Imaging.
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By combining dose-reduction strategies, investigators found IV contrast use for CT scans could be reduced by approximately 80%.

“Contrast is essential in any situation where we need to assess the blood vessels — for example, for some trauma patients or those with a suspected acute gastrointestinal bleed — and it is also needed for evaluation of certain cancers, such as in the liver or pancreas,” Rebecca Smith-Bindman, MD, senior study author and professor in the department of epidemiology and biostatistics at the University of California San Francisco, said in a press release. “However, most CT scans are done for less specific indications, such as abdominal pain in a patient with suspected appendicitis. These can and should be done without contrast during the shortage, because the loss of information in these patients will be acceptable for most patients.”

OT0622Davenport_Graphic_01
Results showed contrast use would be reduced by 12% with weight-based dosing, 25% with reduction of tube voltage and contrast dose, 78% with use of unenhanced CT and 83% with all three approaches combined. Data were derived from Davenport MS, et al. JAMA. 2022;doi:10.1001/jama.2022.9879.

Smith-Bindman and colleagues created models that used five alternative strategies for conserving contrast during CT imaging, including weight-based dosing (model A), reducing contrast dose while reducing tube voltage (model B), replacing contrast CT with unenhanced CT if the American College of Radiology Appropriateness Criteria predicted no more than moderate negative effect on diagnostic accuracy (model C), a combination of models A and C (model D) and a combination of models A, B and C (model E). Researchers estimated the total expected contrast use at baseline and in each of the five hypothetical strategies by applying the rules of each contrast-conserving strategy to observed contrast use in a sample of 1.04 million CT examinations in the University of California San Francisco International CT Dose Registry performed Jan. 1, 2015, to March 11, 2021.

Results showed an estimated 47.1 million mL of contrast was used for the 1 million CT scans in the base case. Researchers found contrast use would be reduced by 12% and 25% with weight-based dosing and by reducing tube voltage and contrast dose, respectively. Use of unenhanced CT instead of contrast-enhanced CT when moderate reduction in diagnostic accuracy is acceptable had the greatest reduction in contrast use by 78%, according to results. Researchers estimated an 83% reduction in contrast use when all three approaches were combined.

“Given the acute shortage, it’s important that clinicians who order imaging exams coordinate with radiology to cancel scans that aren’t absolutely necessary, postpone exams that can be safely delayed, replace CT with MRI and ultrasound where possible and order an unenhanced scan where possible,” Smith-Bindman said in the release. “Further, clinicians should communicate with their patients about why this is necessary. It is crucial that contrast be conserved for clinical situations where its use is essential for accurate diagnosis.”

References

Amid global shortage, study shows how to cut contrast dye use 83%. https://www.ucsf.edu/news/2022/06/423086/amid-global-shortage-study-shows-how-cut-contrast-dye-use-83#:~:text=June%209%2C%202022-,Amid%20Global%20Shortage%2C%20Study%20Shows%20How,Cut%20Contrast%20Dye%20Use%2083%25&text=As%20a%20worldwide%20shortage%20of,)%20by%20up%20to%2083%25. Published June 9, 2022. Accessed June 22, 2022.

Davenport MS, et al. JAMA. 2022;doi:10.1001/jama.2022.9879.