Dr. Shile is Medical Director of the Susan G. Komen Breast Center, Peoria, IL.

Computer-aided detection (CAD) has the potential to improve the practice of screening mammography significantly. While current clinical trials will help define how this technology will enhance the diagnostic efficacy of screening mammography, there is little information on how CAD will affect workload in radiology practices. A study was performed of two suburban, general radiology practices to examine the impact of CAD on the workload of the radiologists and technologists.

Materials and methods

Practice sites--Both radiology practices offer breast imaging services and are staffed by radiologists, who subspecialize in breast imaging, and dedicated breast imaging technologists. Screening mammograms are batch read by the interpreting radiologists several times a day.

CAD technology--The study examined the use of the Second Look* (CADx, Laval, Quebec, Canada) computer-aided detection system. Exam films are batch loaded into the system's digitizer for computer processing. The system's output, known as a Mammagraph, is a paper printout of the screening exam with potentially suspicious masses and microcalcifications identified in the exam images. This output serves as a reading aide to the interpreting radiologist and can be thought of as an independent second opinion to be consulted during exam interpretation.

Data collection--Data was collected in order to identify the amount of additional time required by technical staff and radiologists to process and interpret exams as a result of their use of this CAD technology. Timing data were collected using videocameras mounted in technologists' processing areas (where the Second Look devices were located) and screening mammography reading areas. Videotapes were analyzed by a Mammography Quality Standards Act and board-certified radiologist.

Radiologists--Under institutional review board approved protocols, two radiologists were studied during their interpretation of screening mammograms. They both interpreted and reported on 35 consecutive exams from their practices. After completion of their usual exam interpretation and report, they reviewed each exam with the Mammagraph and modified their interpretation and report as needed. For each exam, the total time for interpretation without the aid of the Mammagraph was determined. This included the amount of time spent assessing the exam with a magnification lens, reporting findings, interpretations, and recommendations. The amount of time added to case interpretation as a result of the radiologist's review of the Mammagraph was also determined.

Technologists--Technologists at both study sites were studied while processing cases. Timed events included removing exam films from X-ray film jackets, arranging and identifying films for Second Look processing, loading cases into the film digitizer, and refiling exam films and associated output into x-ray film jackets. The total amount of technologist time spent on these tasks was determined for 35 screening mammograms at each study site.

Data analysis--Mean and standard deviation, median, minimum, and maximum process times were calculated for the tasks performed by the radiologists and technologists.

Results

Radiologists--Table 1 lists key events during the radiologists' interpretation of exams without the use of the Mammagraph output. The mean time for case interpretation was 1 minute and 16 seconds, which included 16 seconds of assessment with a magnification lens and 16 seconds of case reporting. On average, the use of Second Look technology required an additional 17 seconds per case of a radiologist's time, with a minimum of 3 seconds per case and a maximum of 38 seconds per case (Table 2).

Technologists--On average, an additional 1 minute and 21 seconds of technologist's time was required for case processing by Second Look (Table 3).

Discussion

This study was performed to assess incremental changes in workloads that occur with the use of Second Look CAD technology in screening mammography. For radiologists, average case interpretation time increased from 1 minute, 16 seconds to 1 minute, 33 seconds; an additional 17 seconds. Compared to other events that occur during exam interpretation, it is interesting to note that the work effort created by the use of Second Look is roughly equivalent to that required to assess an exam with a magnification lens, 16 seconds. If its diagnostic efficacy is equally great, one can speculate that CAD will be as essential in mammography interpretation as the magnification lens is today. Clinical trials currently in progress should help to address this issue.

The additional amount of time needed by technologists to implement Second Look CAD technology was 1 minute, 21 seconds. Thus, in facilities where screening mammograms are scheduled at 15 to 20 minute intervals, the findings suggest that technologists can implement the technology as they perform patient exams without any change in patient throughput.

Conclusion

This study was designed to determine the additional amount of time that is required by radiologists and technologists to use computer-aided detection in screening mammography. On average, CAD adds an additional 17 seconds of radiologist's time to the interpretation of a screening exam. This is about the same amount of time that the radiologists in this study used the magnifying lens during exam review. CAD also increases technologist's case processing time by an average of 1 minute and 21 seconds per exam. AR

* Second Look is for investigational use only and is currently not for sale in the United States.