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

  • Valentina IottiEmail author
  • Paolo Giorgi Rossi
  • Andrea Nitrosi
  • Sara Ravaioli
  • Rita Vacondio
  • Cinzia Campari
  • Vanessa Marchesi
  • Moira Ragazzi
  • Marco Bertolini
  • Giulia Besutti
  • Carlo Alberto Mori
  • Pierpaolo Pattacini
  • the RETomo Working Group



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.


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.


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.


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.


Breast neoplasms Mass screening Mammography Workflow Sensitivity and specificity 



Arcispedale Santa Maria Nuova


Azienda Unità Sanitaria Locale


Breast imaging-reporting and data system


Computer-aided detection


Initials of reader 1




Confidence interval


Digital breast tomosynthesis


Ductal carcinoma in situ


Digital mammography


Food and Drug Administration


Interquartile ranges


Istituto di Ricovero e Cura a Carattere Scientifico (Research Hospital)


Mediolateral oblique


Picture archiving and communication system


Initials of reader 2


Initials of reader 3


Synthetic 2D



Many thanks to all the personnel for their committed work during data collection and to all women who participated in the study for their fundamental contribution. We want to sincerely thank Carlo Alberto Mori, MD, for his precious support, devoted work for this study, and inestimable experience in breast diagnosis. The following are also members of the RETomo working group. Screening readers and post-recall assessment: Coriani C, MD; Pescarolo M, MD; Stefanelli G, MD; Tondelli G, MD; Beretti F, MD; Caffarri S, MD. Screening Coordinating Center: Paterlini L, MD. Radiographers Coordinator: Canovi L, Colli M, Boschini M. Scientific direction: Cavuto S; Braglia L. We thank Jacqueline Costa for editing the text. The results of this study were presented orally at a scientific session at the RSNA Annual Meeting in Chicago 2017 and at the ECR in Vienna 2018.


The study has been partially funded by the Regione Emilia-Romagna (Public Health System) and sustained by the institutional funds of the Reggio Emilia Local Health Authority (AUSL)-IRCCS.

Compliance with ethical standards


The scientific guarantor of this publication is Paolo Giorgi Rossi, PhD.

Conflict of interest

VI, AN, RV, and PP have received speakers’ fees and travel grants from GE Healthcare. CAM received financial support from GE Healthcare to allow the conclusion of the study after his retiring.

PGR, SR, CC, VM, MR, and MB disclosed no relevant relationships.

Statistics and biometry

One of the authors (Paolo Giorgi Rossi, PhD) has significant statistical expertise.

Informed consent

Written informed consent was obtained from all subjects (patients) in this study.

Ethical approval

Institutional Review Board approval was obtained.


• Retrospective

• Diagnostic or prognostic study

• Performed at one institution


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Copyright information

© European Society of Radiology 2019

Authors and Affiliations

  • Valentina Iotti
    • 1
    Email author
  • Paolo Giorgi Rossi
    • 2
  • Andrea Nitrosi
    • 3
  • Sara Ravaioli
    • 1
  • Rita Vacondio
    • 1
  • Cinzia Campari
    • 4
  • Vanessa Marchesi
    • 1
  • Moira Ragazzi
    • 5
  • Marco Bertolini
    • 3
  • Giulia Besutti
    • 1
    • 6
  • Carlo Alberto Mori
    • 1
  • Pierpaolo Pattacini
    • 1
  • the RETomo Working Group
  1. 1.Radiology UnitAUSL Reggio Emilia, IRCCSReggio EmiliaItaly
  2. 2.Epidemiology UnitAUSL Reggio Emilia, IRCCSReggio EmiliaItaly
  3. 3.Medical Physics UnitAUSL Reggio Emilia, IRCCSReggio EmiliaItaly
  4. 4.Screening Coordinating UnitAUSL Reggio Emilia, IRCCSReggio EmiliaItaly
  5. 5.Pathology UnitAUSL Reggio Emilia, IRCCSReggio EmiliaItaly
  6. 6.Clinical and Experimental Medicine PhD ProgramUniversity of Modena and Reggio EmiliaModenaItaly

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