acrin breast committee fall meeting 2010 4006: comparison of full-field digital mammography with...

ACRIN Breast Committee

ACRIN Breast CommitteeFall Meeting 2010

4006: Comparison of Full-Field Digital Mammography with Digital Breast

Tomosynthesis Image Acquisition in Relation to Screening Call-Back Rate

Emily F. Conant, MD Constantine Gatsonis, PhD



Digital Breast Tomosynthesis

Disclosures:

GE Support (P.I. E. Conant): A Multicenter Study to Test the Non-Inferiority of Digital Breast Tomosynthesis (DBT) Compared to Full-Field Digital Mammography(FFDM) in Detecting Breast Cancer

E.Conant: Consultant to Hologic


Study Summary


Limitations of Mammography

Tissue superimposition

Projection Projection imagingimaging

DetectorDetector

BreastBreast

Compression Compression PlatePlate

X-raysX-rays


Digital Breast Tomosynthesis (DBT)

Multiple low dose digital mammographic images are obtain along an arc and then reconstructed into a stack of images




Tomographic Tomographic ImagingImaging

Tube Tube RotationRotation

DetectoDetectorr

BreastBreast

X-raysX-rays

Compression Compression PlatePlate



Vendors have varied approach to DBT:• Image acquisition

– Angle of acquistion, number of images in arc• Continuous arc image acquisition• “Stop and shoot” image acquisition

• Stand alone screening tool versus adjunct to full field digital mammography (FFDM)– Single view MLO DBT (no FFDM)– Two view DBT plus FFDM



• Preliminary experience has suggested that digital breast tomosynthesis (DBT) may provide:

– Better specificity leading to reductions in recall rates

– Improvements in sensitivity and the depiction of the extent of disease



Issues?• Few published trials • Results stress specifity as measured by reduction in

recall rates• Most are single institution, single vendor

– Technical approach varies greatly by vendor…

Little published data on impact of tomosynthesis on sensitivity in breast cancer screening



Multi-center trial of 1957 pts• Compared FFDM and DBT recall rates

– 43% reduction in recall rate Rafferty et al. RSNA 2007:SSG01-01

Single institution trial of 98 pts• Compared FFDM and DBT recall rate

- 40% reduction in recall ratePoplack et al. AJR

2007;189(3):616-623

Single institution trial of 125 selected studies• FFDM alone, DBT alone and FFDM/DBT combo

- 30% decrease recall rate with combo, 10% DBT aloneGur et al. AJR

2009;193:586-591



Two views versus one view tomo?• Results

– 22/34 (65%) both projections equal– 4/34 (12%) much better seen on MLO projection– 5/34 (15%) much better seen on CC projection– 3/34 (9%) seen only on the CC projection

Imaging in both CC and MLO positions is optimal

Rafferty et al:RSNA 2006;SSG01-04


What about calcifications in DBT?

• 98 recalled cases– “image quality of tomosynthesis was inferior to

diagnostic mammography” in characterization of calcsPoplack et al. AJR

2007;189(3):616-623

• 119 DBT cases with calcifications– Approx. 50%, DBT = FFDM– Approx. 40%, DBT > FFDM

Kopans et al. RSNA 2008 SSJ01-02.

Motion artifact in DBT



Hypothesis

• Digital breast tomography (DBT) will improve the specificity of breast cancer screening as measured by a reduction in the call-back rate while maintaining the sensitivity of cancer detection. – This improved accuracy will be achieved by the

optimization of the imaging sequence and number of views obtained at a capped radiation dose in the combined DBT and 2-D screening sequence


Eligibility and Sample Size

• Screening Group A (n=500) : – Women presenting for screening > 25 yrs

• Enrichment Group B (n=50) : – Women called back from FFDM screening for

diagnostic imaging

Total Accrual = 550 cases


Study Design

• Standard of Care clinical study: – 3 view digital mammogram

• Study Imaging: – 2 view tomosynthesis (MLO and CC) and low dose 2-

D MLO– Sequential read of study low dose 2-D CC view.

Studies read independently therefore, call-backs determined independently


Specific Aims

• Primary Aim: – Compare recall rates of FFDM to limited DBT set

(Group A)

• Secondary Aims: – To compare sensitivity of FFDM to the limited DBT

set (Groups A and B)

– To assess lesion-type characterization: • To compare sensitivity and specificity by lesion-type (calc only

lesions versus soft-tissue lesions, as well as lesion subgroups: masses, calcs, architectural distortions, asymmetries) in FFDM versus DBT.

• To estimate the agreement of FFDM and DBT with the determination of the adjudication committee on lesion-type characterization.


Additional Aims

• Secondary Aims, continued: – To use the sequential interpretation results [Groups A and B] to

compare the two-view limited tomosynthesis set (with low-dose MLO view alone) with the tomosynthesis plus set (addition of low-dose CC view) on the basis of:

• Call-back rate;• Identification of new lesion(s);• Lesion characterization; and• Triangulation

– To calculate and compare the radiation dose of the FFDM and the DBT sets

– To identify the determinants of participant radiation dose and clinical image quality, including factors such as kVp, mAs, target/filter combination, and breast thickness and composition


Recruitment

• Patients to be recruited over a 1 year period

• Trial scheduled to open 10/6/10 at Pennsylvania sites:

– Hospital of the University of Pennsylvania– Einstein Medical Center

• Limited to one industry since only one vendor in PA – Hologic


Future Tomosynthesis Trials?

Optimize imaging for tomosynthesis• Which combinations of 3-D and possibly 2-D images?

• Decision based on risk/benefit for individual patient?

• Optimization of dose based on task?

Trial powered for sensitivity?• High/intermediate risk patients (+/-MR)?

How do we best utilize tomosynthesis for diagnostic imaging?

acrin breast committee fall meeting 2010 4006: comparison of full-field digital mammography with...

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