Comparing two visualization protocols for tomosynthesis in screening: specificity and sensitivity of slabs versus planes plus slabs.

OBJECTIVES: Tomosynthesis (DBT) has proven to be more sensitive than digital mammography, but it requires longer reading time. We retrospectively compared accuracy and reading times of a simplified protocol with 1-cm-thick slabs versus a standard protocol of slabs + 1-mm-spaced planes, both integrated with synthetic 2D. METHODS: We randomly selected 894 DBTs (including 12 cancers) from the experimental arm of the RETomo trial. DBTs were read by two radiologists to estimate specificity. A second set of 24 cancers (8 also present in the first set) mixed within 276 negative DBTs was read by two radiologists. In total, 28 cancers with 64 readings were used to estimate sensitivity. Radiologists read with both protocols separated by a 3-month washout. Only women that were positive at the screening reading were assessed. Variance was estimated taking into account repeated measures. RESULTS: Sensitivity was 82.8% (53/64, 95% confidence interval (95% CI) 67.2-92.2) and 90.6% (95% CI 80.2-95.8) with simplified and standard protocols, respectively. In the random screening setting, specificity was 97.9% (1727/1764, 95% CI 97.1-98.5) and 96.3% (95% CI 95.3-97.1), respectively. Inter-reader agreement was 0.68 and 0.54 with simplified and standard protocols, respectively. Median reading times with simplified protocol were 20% to 30% shorter than with standard protocol. CONCLUSIONS: A simplified protocol reduced reading time and false positives but may have a negative impact on sensitivity. KEY POINTS: • The adoption of digital breast tomosynthesis (DBT) in screening, more sensitive than mammography, could be limited by its potential effect on the radiologists' workload, i.e., increased reading time and fatigue. • A DBT simplified protocol with slab only, compared to a standard protocol (slab plus planes) both integrated with synthetic 2D, reduced time and false positives but had a negative impact on sensitivity.

Impact of the Introduction of Digital Mammography in an Organized Screening Program on the Recall and Detection Rate.

In 2012, the Reggio Emilia Breast Cancer Screening Program introduced digital mammography in all its facilities at the same time. The aim of this work is to analyze the impact of digital mammography introduction on the recall rate, detection rate, and positive predictive value. The program actively invites women aged 45-74 years. We included women screened in 2011, all of whom underwent film-screen mammography, and all women screened in 2012, all of whom underwent digital mammography. Double reading was used for all mammograms, with arbitration in the event of disagreement. A total of 42,240 women underwent screen-film mammography and 45,196 underwent digital mammography. The recall rate increased from 3.3 to 4.4% in the first year of digital mammography (relative recall adjusted by age and round 1.46, 95% CI = 1.37-1.56); the positivity rate for each individual reading, before arbitration, rose from 3 to 5.7%. The digital mammography recall rate decreased during 2012: after 12 months, it was similar to the recall rate with screen-film mammography. The detection rate was similar: 5.9/1000 and 5.2/1000 with screen-film and digital mammography, respectively (adjusted relative detection rate 0.95, 95% CI = 0.79-1.13). The relative detection rate for ductal carcinoma in situ remained the same. The introduction of digital mammography to our organized screening program had a negative impact on specificity, thereby increasing the recall rate. The effect was limited to the first 12 months after introduction and was attenuated by the double reading with arbitration. We did not observe any relevant effects on the detection rate.

MRI patterns of invasive lobular breast cancer.

Dr. Schelfout and colleagues, in the March 2004 issue of European Radiology described six tumor morphologic patterns of invasive lobular breast cancer. We retrospectively compared findings on preoperative MR imaging in 18 patients with invasive lobular cancer performed at our institution and we found an additional morphologic pattern in our population: a mass with regular margins (five cases).