Analysis of Technical Repeat Studies in Screening Mammography

Objective: To identify causes of technical repeats, determine whether differences exist between mobile and fixed mammography units, and evaluate the rate of improvement on repeat imaging. Methods: IRB approval was obtained for retrospective review of Enhancing Quality Using the Inspection Program (EQUIP) logs of screening mammography technical repeats performed from March 2017 to December 2018 at a hospital breast imaging center and from April 2017 to December 2018 on mobile mammography units. Frequency tables and Fisher's exact tests were used for statistical analysis. Results: Technical deficiencies were reported in 483 cases and reviewed by two or three auditors. Auditors identified no technical deficiencies in 31 cases, which were excluded. The remaining 452 cases were assigned a technical recall category: motion, positioning/excluded tissue, skin folds, artifacts, undercompression, or contrast (under/overexposure). Motion was the most common technical recall category (253/452, 56.0%). Positioning/excluded tissue was the second most common reason (150/452, 33.2%). Statistically significant differences in technical deficiencies were identified between mammograms performed on mobile versus fixed mammography units for motion (94/143, 65.7% vs 159/309, 51.5%, respectively, P = 0.0058), skin folds (16/143, 11.2% vs 15/309, 4.8%, respectively, P = 0.02), and positioning/excluded tissue (30/143, 21% vs 120/309, 38.8%, respectively, P = 0.00016). Most recalls improved with repeat imaging (auditor 1: 451/483, 93% and auditor 2: 387/483, 80%). Conclusion: Motion and positioning/excluded tissue are the most common reasons for screening mammography technical recalls. The reasons for technical recall differ between patients imaged on mobile and fixed mammography units, likely because of differences in each location's patient population.