breast tomosynthesis reduces breast tomosynthesis reduces

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  • 1. Breast tomosynthesis reduces radiologist performancevariability compared to digitalmammographyAndrew Smith1, Elizabeth Rafferty2, Loren Niklason1 1 Hologic,Inc., Bedford MA, USA2 Massachusetts General Hospital, Boston MA,

2. Study GoalsMeasure radiologist variability ofperformance of 2D+3D comparedto 2D: Area under ROC curve Decision to recall 3. Tomosynthesis Acquisition X-ray tube Compression plateReconstructed1 mm planes BreastDigitaldetector X-ray tube moves in an arc across the breast 11 projections over 15 Total tomo dose matched to 2D dose (FFDM) Reconstruction into 1 mm transverse slices 4. Data CollectionStudy tomo in screening environment. 1000patients. Diagnostic needed to enrich with cancers.Imaged using 2D (FFDM: Selenia),Imaged using 3D (Tomosynthesis prototype)Both views (CC, MLO), both breasts.Previous studies suggest both CC and MLO tomoneeded for optimal performanceInstitution Review Board/Informed patient consent 5. Why 3D+2D, and not 3D alone?Tomosynthesis (3D) will reduce tissueoverlap compared to FFDM (2D), mostlyneeded for massesHaving 2D exam speeds up search formicrocalcificationsThere will be a transition period when 2D isuseful: comparison to priors, use of 2D as goldstandard.System supports single breast compressionacquisition of both 2D and 3D 6. Acquisition showing 3D followed by 2D exam 7. Reader Study Protocol~310 patients, includes normals, recalls,benign lesions and 51 cancers27 readers, radiologists with range ofmammography experienceReaders had no prior experience withtomosynthesisReaders were trained over 2 day session 8. Assessment MethodologyRead images on dedicated mammography workstationRead and score the 2D:Initial BIRADS 0, 1, or 2Forced BIRADS (1-5)Probability of Malignancy (POM) from 0 to 100%Read 3D and score (2D+3D) using same methodsInitial BIRADS 0, 1, or 2Forced BIRADS (1-5)Probability of Malignancy (POM) from 0 to 100% 9. Data Analysis Compare 2D and (2D+3D) Compute ROC curve from Probability ofMalignancy ROC analysis: Multi-reader multi-caseDBM MRMC Beta 2 software 10. Examples of readers ROC curves 11. ROC Analysis:Area under ROC Curve (AUROC)AUROC of 3D+2D superior to 2D forevery readerLook at radiologist variation, i.e.standard deviation of AUROCEquality of Variance test forstatistical significance 12. Radiologist Variability with 2D and 2D+3D2D+3D2D 13. All Cases2D2D+3DMean0.825 0.895AUROCStandard0.032 0.023DeviationAUROCAUROC 2D+3D variability 72% of 2D,variances equal p=0.11 14. Averaged ROC CurvesAll cases Calcs only No calcs 15. Cases involving Calcifications 2D2D+3D Mean0.840 0.856 AUROC Standard0.051 0.048 Deviation AUROCAUROC 2D+3D variability 93% of 2D,variances equal p=0.73 16. Cases without Calcs2D2D+3DMean0.827 0.922AUROCStandard0.044 0.027DeviationAUROCAUROC 2D+3D variability 63% of 2D,variances equal p = 0.02 17. Decision to Recall,non-cancer cases (BIRADS 0)2D 2D+3DAgreed on 70.9%78.7%recalldecisionKappa 0.4130.530Kappa differences statistically significant 18. Image Examples 19. False PositiveDigital MammogramTomosynthesis Image 20. CancerDigital MammogramTomosynthesis Image 21. ConclusionsTomosynthesis previously shown to improveradiologist performance: 3D+2D compared to2DVariability of AUROC reduced when using 3D,for cases not involving calcifications, p = 0.02Variability unchanged for calc casesRadiologists are more accurate (AUROC) andmore confident (Variances) with 3D+2D,compared to 2D for mass detectionRadiologists agreed more often on decision torecall non-cancer cases with 2D+3D than 2D 22. More on the same subjectElizabeth Rafferty, MDMassachusetts General Hospital, Boston MA, USAInter-reader variability: Comparing breasttomosynthesis combined with FFDM to FFDM aloneMulti-center, retrospective study: Comparing breasttomosynthesis combined with FFDM to FFDM aloneSunday, March 8, 14:00-15:30Satellite Symposium, Room F2 23. Thank youImages and data courtesy of: Massachusetts General Hospital, Boston MA USA Netherlands Cancer Institute Antoni Van Leeuwenhoek Hospital, Amsterdam Holland Centre de Radiologie et dEchographie du Docteur Joussier, Paris France Dartmouth Hitchcock Medical Center, Lebanon NH USA Magee Womens Hospital, Pittsburgh PA USA University of Iowa Health Care, Iowa City IA USA Yale University School of Medicine, New Haven CT USA


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