In a recent study published by PLOS Medicine, a team of researchers analyzed more than 11,000 patients ages 14 year and older with blunt trauma, creating two decision instruments they believe could reduce unnecessary chest CTs by approximately 25 to 37 percent.

Robert M. Rodriguez, MD, of the University of California, San Francisco, department of emergency medicine, and colleagues examined the presence or absence of 14 clinical criteria in more than 6,000 patients ages 14 years and older with blunt trauma before viewing the chest CT results.

That research helped the team form two decision instruments—Chest CT-All and Chest CT-Major—which could potentially help future patients receive an accurate diagnosis with less or no exposure to CT scans.

“The Chest CT-All decision instrument, which maximized sensitivity (the ability to correctly identify people with a condition) for either major and minor chest injuries, consisted of seven clinical criteria including an abnormal x-ray, rapid deceleration mechanism (trauma caused by, for example, a road collision occurring at more than 40 mph), and bone tenderness (pain that occurs when an area is touched) in the chest,” the authors wrote. “The Chest CT-Major instrument, which maximized sensitivity for only major chest injuries, consisted of the same criteria without rapid deceleration mechanism.”

The authors’ next step was testing their work. They used the decision instruments to diagnose an additional 5,475 patients ages 14 years and older with blunt trauma, making their own determination before the chest CT results were viewed. They could then compare their verdict with the final, post-CT diagnosis and gain an understanding of the decision instruments’ true accuracy.

And how did they do? The criteria within the Chest CT-All instrument identified 95.4 percent of patients with a major or minor injury as having an injury. The criteria within the Chest CT-Major instrument identify 99.2 percent of patients with a major injury.

This high level of accuracy, the authors concluded, could reduce unnecessary chest CT scans on trauma patients by approximately 25 to 37 percent.

“Because the use of these instruments allows clinicians to identify virtually everyone who has this type of injury, clinicians can forego CT in patients who do not exhibit any of the decision instrument criteria for blunt chest injury,” the authors wrote. “That is, clinicians can safely use physical examination and history findings, instead of imaging, to rule out blunt chest injury in many patients attending a trauma center.”

Rodriguez et al. warned that these decision instruments are meant to augment clinical judgement, not replace it altogether. In addition, they said these are not valid when attempting to diagnose younger patients.

“Given that the radiation risks of chest CT are higher in younger patients and may be negligible in elderly patients, providers may wish to apply our [decision instruments] differentially by age,” the authors wrote.

The full study is available on the PLOS website.