Study: Digital mammo shortens acquisition time, but not interpretation time

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Digital mammography can significantly shorten the acquisition time for diagnostic mammography, but there is no significant difference in interpretation time compared with screen-film mammography in a diagnostic mammograms setting, according to a study in the September issue of Academic Radiology.

Cherie M. Kuzmiak, DO, from the department of radiology at the University of North Carolina Lineberger Comprehensive Cancer Center in Chapel Hill, N.C., and colleagues noted that 53 percent of U.S. mammography facilities had one or more full-field digital mammographic units as of December 2009 and clinical use in the U.S. continues to increase. The researchers sought to determine whether the acquisition and interpretation times of soft-copy digital mammography is faster compared to screen-film mammography in the diagnostic mammography center setting.

The researchers conducted their study in three phases for patients presenting for clinical diagnostic workup to a mammography clinic. Four experienced breast imaging radiologists and seven technologists participated in all phases of the study.  One hundred patients participated in phases one and two, and 95 patients were involved in phase three of the study.

Technologist acquisition and processing times and radiologist interpretation times were measured for patients imaged with a screen-film mammographic system in the first phase. The second phase measured times for patients imaged with a direct radiographic digital mammographic system with interpretation performed on a soft-copy display system. Times were measured again three months after installation of the soft-copy display system for patients imaged on the same direct radiographic digital mammographic system with interpretation on the same soft-copy system in the third phase of the study.

Kuzmiak and colleagues determined that diagnostic mammographic acquisition times with processing were 13.02 minutes per case for screen film in phase one, 8.16 minutes per case for digital in phase two and 10.66 minutes per case for digital in phase three.

In addition, the mean interpretation times were 3.75 minutes per case for screen film in phase one, 2.14 minutes per case for digital in phase two and 2.26 minutes per case for digital in phase three.

Researchers determined that one reader's mean screen-film interpretation time was an outlier. When his results were excluded, there was no significant difference in interpretation time among the remaining three readers between film and digital soft-copy display, wrote the authors. “The radiologist interpretation time for digital mammography in both phases was not significantly different from that for film mammography [and] there was no significant difference between phases two and three,” continued the authors.

Attributing the time saved per diagnostic mammographic examination to the elimination of processing time, Kuzmiak and colleagues explained that their results demonstrate that a diagnostic mammographic examination using a direct radiographic fixed-detector full-field digital mammographic system can significantly shorten the time of the examination.

“Compared to screen-film mammography in phase one, the direct radiographic digital system used in phases two and three decreased the mean acquisition time with processing time by an average of 3.61 minutes per case (27.7 percent),” they offered.

The researchers believe that the results of their study provide support to radiologists for conversion to direct radiographic digital diagnostic mammography in the clinic setting. “Patients' examination times are significantly shortened by the elimination of film processing. In addition, interpretation time performance with a soft-copy display system can be equivalent to screen-film interpretation,” Kuzmiak and colleagues concluded.