Image Quality and Performance Benchmarks in Vehicle and Hospital Mammography

Background: Whether the quality and clinical performance of mammograms obtained in vehicles and those obtained in fixed facilities are equal remains unknown. We compared the characteristics of examinees screened in hospital and vehicle settings. Patients and Methods: Data from women who had undergone mammography at Shuang Ho Hospital from January 1, 2013, to December 31, 2016, were obtained from the Women's Breast Screening Database and used for analysis. The records revealed that 43,807 and 11,955 women had undergone mammography in vehicle and hospital settings, respectively. The performance benchmarks, including recall rate, cancer detection rate, and positive predictive value, in the 2 settings were compared. In addition, the image quality was compared by reviewing 110 records from each setting. Results: The hospital mammograms had greater subtotal mean scores (189.2 ± 5.9) compared with the vehicle mammograms (185.5 ± 7.7; P < .0001) in the mediolateral oblique view. Mobile mammography contributed to a lower odds ratio of classification in the Breast Imaging Reporting and Data System categories of 0, 4, and 5. In general, all performance benchmarks, including the cancer detection rate and positive predictive value of mobile and hospital mammography, were satisfactory. However, the recall rate with the hospital mammography service was slightly greater than the acceptable benchmark. Conclusion: Mobile mammography services should be continued with improvements in image quality. The reduction in the number of patients with a category of 0 in the classification system in both mammography service settings and the enhancement of data linking to previous mammograms warrants additional attention.