Chest tomosynthesis (CTS) could streamline radiological work-up logistics as well as optimize an institution’s CT resources and reduce effective radiation doses, according to a study published this month in Academic Radiology.

Åse A. Johnsson, MD, PhD, from the University of Gothenburg in Sweden, and colleagues sought to investigate potential benefits and drawbacks of the clinical use of CTS in terms of it precluding the need for an additional chest CT. They examined results from 149 individual CTS scans that occurred in March 2010.

CTS and lesion detection

For each case studied, researchers determined whether CT would have been performed if the CTS had not been available, and whether the CTS was an adequate substitution—a decision based on the status of the patient and the clinical and radiological information available prior to the CTS.

In cases in which researchers judged that CT would have been performed had CTS not been an option, a determination was made on whether the use of CTS had been beneficial, neutral or detrimental.

The CTS was deemed beneficial if it verified a suspected chest lesion that had been detected during a chest x-ray and resulted in an adequate work up with CT or if the CTS correctly dismissed a suspected lesion.

If an adverse event had been reported (a finding of pulmonary pathology during the follow-period), the CTS was determined to be detrimental. Cases were determined to be neutral if the CTS examination did not affect radiological work up and the patient still had to undergo CT.

Johnsson and team found that of the 149 studied CTS cases, CT would have been performed in 100 of those cases had CTS not been available.

Further, they determined CTS obviated the need for CT in 80 cases. CTS was judged as beneficial in 85 cases, neutral in 13, and detrimental for the radiological work-up in two cases.

CTS and radiation

Dose data collected from initial exams was used to determine the patient-averaged dose-area product (DAP) from each type of examination. These data sets were converted to estimations of effective radiation doses.

To determine any potential benefits on radiation dose levels with the use of CTS, the dose to patients was compared to doses that hypothetically would result from the alternative scenario, in which CTS was not available and either a CT or chest x-ray would have been performed on the patient.

The research team found, that in all 149 cases studied, the use of CTS decreased the average effective radiation dose from 2.7 to 0.7 mSv.

Despite the promising findings on CTS use, Johnsson and colleagues asserted that it was not always the best course to take.

“A drawback is that CTS examinations may fail to reveal pathology visible with CT,” they wrote. “In clinically doubtful cases, further investigations including other imaging procedures should be therefore considered.”