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Digital Breast Tomosynthesis
02.04.2014 UK SH International Master Program Biomedical Engineering Digital Breast Tomosynthesis from a first idea to clinical routine Historical background • 2D imaging of 3D objects has important limitations Jörg Barkhausen Clinic for Radiology and Nuclearmedicine, University Hospital Schleswig‐Holstein Campus Lübeck UK SH UK SH Clinical Example Historical background • 2D imaging of 3D objects has important limitations • Request: to generate 3D information out of several 2D x‐ray images • First ideas were published by Ziedes des Plantes in 1931 UK SH UK SH Planography Planography • Basic idea: relative movement of the x‐ray‐tube, the image receptor • Result: a single plane is displayed sharply, and all other structures are blurred (out of focus) • Limitation: only one plane per scan, 3D coverage increases radiation dose Pollak B, 1953 1 02.04.2014 UK SH UK SH Planography Planography Pollak B, 1953 Pollak B, 1953 UK SH UK SH Planography Planography UK SH UK SH Digital Tomosynthesis Digital Tomosynthesis • Basic idea by Miller et al. in 1971: production of an infinite number of planar slices from a finite number of radiographs • Equipment: linear tomographic x‐ray machine, fluoroscope and TV system, video recorder, analog to digital converter and a computer • Several clinical applications including angiotomography Maravilla KR, AJR 1983 Maravilla KR, AJR 1983 2 02.04.2014 UK SH UK SH Digital Tomosynthesis Clinical background • Breast cancer is the most common malignancy in women • Worldwide, breast cancer comprises 10.4% of all cancer incidence among women • Prognosis and survival rate varies greatly depending on staging Level of the internal auditory canal Level of the orbits and facial structures • Early detection is most crucial Maravilla KR, AJR 1983 UK SH UK SH Mammography Mammography: Advantages • Fast • Non‐ expensive • Accurate • Detects Microcalcification and Masses • Allows for breast cancer screening UK SH UK SH Mammography Typical findings: stellate lesion 3 02.04.2014 UK SH UK SH Typical findings: stellate lesion Calcifications solitary, large calcification with smooth margins benign UK SH UK SH Reasons for Nondetection of Cancer Breast Ultrasound clustered, irregular, small calcifications suspicious • 335 US‐depicted cancers, 56% > 10 mm • Review of mammograms by 5 radiologists • 81% (272 / 335) of cancers were not seen at mammography even in retrospect • 78% (263 / 335) of cancers were obscured by overlapping dense tissue Bae MS, Radiology 2014 UK SH UK SH Breast MRI First idea: Digital Breast Tomosynthesis Niklason LT, Radiology 1997 4 02.04.2014 UK SH UK SH Digital Breast Tomosynthesis Mastectomy specimen • X‐ray tube moves in an arc • Stationary breast tissue • Stationary digital detector • Low‐radiation‐dose images were acquired using step‐and‐expose method • 2 phantoms and 4 mastectomy specimen Mammography Niklason LT, Radiology 1997 Digital Tomosynthesis Niklason LT, Radiology 1997 UK SH UK SH Digital Breast Tomosynthesis (DBT) Digital Breast Tomosynthesis in Lübeck • Mammomat Inspiration • Digital Mammography • Stereotactic Breast Biopsy • Digital Breast Tomosynthesis (DBT) • 25 projections • 50° angle UK SH UK SH Different DBT Systems Angular range System GE Essential Hologic IMS Selenia Giotto Dimension s Philips Micro Dose Planmed Nuance Excel DBT Siemens MAMMOMAT Inspiration Detector type Full‐field indirect Full‐field direct Full‐field direct Linear slit scan Full‐field direct Full‐field direct Detector size 24 x 30 cm 24 x 29 cm 24 x 30 cm 21 Lines, 24 cm 24 x 30 cm 24x 30 cm Detector pixel size 100 µm 70 µm 85 µm 50 µm perpendicular to motion 85 85 X‐ray tube motion Step & Shoot Cont. Step & Shoot Cont. Cont. Cont. 9 15 13 21 15 25 Number of projectionen Angular range 25° 15° 40° 11° 30° 50° Scan time 7 s 3,7 s 12 s 3‐10 s 20 s 25 s 5 02.04.2014 UK SH UK SH How to read DBT How to read DBT 2D 2D 3D‐ DBT UK SH UK SH Focus Focal Lesions FFDM 3D‐ DBT DBT UK SH UK SH Focal lesions Prerequisites for clinical routine • Robust and commercially available hardware (not too expensive) • Some excellent clinical examples • Enthusiastic physicians 6 02.04.2014 UK SH UK SH Case 1 Lesion visible only in one standard view Case 2 Case 3 Courtesy I. Andersson UK SH UK SH Case 2: 8 mm invasive Carcinoma Case 3: no mass at DBT UK SH UK SH Case 3: additional MRI Prerequisites for clinical routine • Robust and commercially available hardware (not too expensive) • Some excellent images • Enthusiastic physicians • Low radiation MRM, subtraction, 4 min after contrast 7 02.04.2014 UK SH UK SH Radiation exposure Radiation exposure • Compressible water‐oil mixture phantoms • Full‐field digital mammography (FFDM) • Digital breast tomosynthesis (DBT) • Single craniocaudal view • Mean glandular dose (MGD) for different breast of varying sizes and glandular compositions Mammo cc Single Projektion DBT (25 Projections) Mammo mlo AGD 1,05 mGy AGD 0,06 mGy AGD 1,46 mGy AGD 1,28 mGy Feng SS, Radiology 2012 UK SH UK SH Radiation exposure Prerequisites for clinical routine • FFDM MGD 0.309 – 5.26 mGy • DBT MGD 0.657 – 3.52 mGy • Robust and commercially available hardware (not too expensive) • Compressed thickness 5 cm, 50 % glandular fraction • Some excellent images • FFDM 1.2 mGy • Enthusiastic physicians • DBT 1.3 mGy ( +8% ) • Low radiation • Single view DTB reduces dose compared standard two view FFDM • Data from large clinical trials Feng SS, Radiology 2012 UK SH UK SH Screening: DM versus DM + DBT 48 yo, screening • 2011 to 2012, multicenter trial • 13.158 patients presented for Screening Mammography, 6.100 received additional DBT • Tumor detection rate DM 5,2 • Recall rate DM + DBT 5,7 DM 12% DM + DBT 8,4 % • Greatest reduction in recall rate occurred in women with dense breasts and those younger than 50 Haas BM, Radiology 2013 8 02.04.2014 UK SH UK SH 48 yo, screening Head to head comparison ADH Cyst • In none of the available smaller studies DBT was inferior to digital mammography • Detection of microcalcification with DBT !? • Most studies suffer from a selection bias, only women with abnormal DM included • Malmö Breast Tomosynthesis Screening Trial (MBTST) with 15000 subjects started in 2010 UK SH UK SH Cancer or no cancer? Additional tomosynthesis UK SH UK SH Additional tomosynthesis Additional MRI without contrast with contrast Slice 13 Slice 21 Slice 32 Slice 46 subtraction 9 02.04.2014 UK SH Conclusion • Digital breast tomosynthesis is technically ready for clinical use • All published studies showed excellent results for digital breast tomosynthesis • We need more clinical studies • DBT will change our algorithm in breast imaging within the next 5 years 10
