Offshoot of digital mammography could provide alternative to breast MRI

An adaptation of digital mammography could cut image acquisition times and provide a new screening method to patients unable to undergo breast MRI, but added time commitments could make the technique difficult to implement in clinical practice, a case study published in the Journal of the American College of Radiology suggests.

Contrast-enhanced spectral mammography, or CESM, is a a subset of digital mammography that uses intravenous contrast to analyze breast cancer using a dual-energy technique, first author Jordana Phillips, MD, and colleagues at Harvard Medical School wrote. Screening technicians obtain both high- and low-energy images in this approach, with the former highlighting areas of contrast intake and the latter producing an image similar to conventional 2-D mammography. The images are then merged for evaluation.

CESM has in studies demonstrated higher sensitivity for breast cancer detection compared with run-of-the-mill digital mammography, Phillips et al. said. It’s also cheaper than an MRI and easier to implement into practice, since CESM equipment is an add-on to the mammography equipment most facilities already have in place.

The method was approved by the FDA in 2011 for use as an alternative diagnostic tool. CESM is especially helpful to patients who can’t undergo breast MRI, the authors wrote.

Phillips and her team reviewed a handful of CESM exams from their practice, which implemented the imaging technique in late 2014. Performing technologists recorded time metrics during each examination—including equipment setup time, patient setup time, exam and post-exam time, and aggregate time—and similar metrics were recorded for digital diagnostic mammography (DM), breast MRI and contrast-enhanced CT for comparison.

In all, 38 CESM cases were included in the trial, according to the study, as well as 34 digital mammograms, 25 breast MRIs and 44 contrast-enhanced CTs.

“Our study helped quantify the additional time required to perform CESM,” Phillips and colleagues wrote. “We found that CESM had a similar examination time to DM and was significantly shorter than breast MRI, providing an appealing diagnostic alternative to breast MRI. However, the aggregate time for CESM was increased by 33 minutes above DM for a total aggregate time of 56 minutes.”

That increased aggregate time, the authors said, slowed down their integration of CESM into daily practice. They said that increased patient and equipment setup times were largely to blame—mostly due to IV placement—though a comparison with contrast-enhanced CTs led the researchers to believe those setup times could be reduced by as much as 21 minutes. That would mean CESM aggregate time would sink closer to that of digital diagnostic mammography.

“For any busy practice, incorporating a new imaging technique into daily workflow can be a challenge,” Phillips and co-authors said. “In this study, we identified how the different steps involved in CESM affect workflow in our practice.”