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COMPARISON OF DEDICATED DIGITAL SPECIMEN RADIOGRAPHY WITH DIRECT DIGITAL SPECIMEN MAMMOGRAPHY IMAGES
J Morel, V Milnes, A Iqbal, R Wasan, C Peacock, D Evans, M Michell, Breast Radiology and NaBonal Breast Screening Training Centre, King's College Hospital, Denmark Hill, London, United Kingdom
Introduction Specimen radiography is a long established procedure for confirming the p resence o f bo th ca l c i f i ed and noncalcified targeted lesions after needle localization and surgical excision(1,2) and to confirm the presence of targeted mic roca l c i f ca t i on fo l l ow ing co re biopsy(3). With the digitalization of breast radiology it is possible to perform rapid digital specimen radiography with a standard direct digital mammography unit. Prior to digital mammography specimen radiography has been performed on dedicated digital specimen equipment but with significant loss of sensitivity compared to screen/film mammography. Therefore these dedicated systems have been used for their rapidity but a film/screen image has been required in addition due to poorer image quality. This study aims to compare the image quality obtained from a new generation digital specimen radiography system with the image quality from a standard direct digital mammography unit.
Methods All surgical and core biopsy samples taken within our department during the study period were imaged with both a Direct Digital Radiography (DDR) unit and a Digital Specimen Radiography System(DSRS). The systems used in the study were Hologic Dimensions digital mammography and the Bioptics BioVision digital specimen radiography system. WLE specimens were imaged without magnification on both systems. Biopsy s p e c i m e n s w e r e i m a g e d w i t h magnification. Two film readers assessed each set of images side by side. F o r a l l s p e c i m e n s c o n t a i n i n g microcalcif ications the number of microcalcifications was recorded as 0, <5, <10, <15, <20, >20. In addition the visibility of each lesion was assessed on a 4 point scale where 1 signifies that the lesion is not visible and 4 signifies the lesion is well seen.
Conclusions
References 1)Gallager hs, Breast specimen radiography: obligatory, adjuvant, and investigative. Am J Clin Pathology 1975;64:749-755 2)Stomper PC, Davis SP, Sonnenfeld MR, Meyer JE, Greenes RA, Eberlein TJ, Efficacy of specimen radiography of clinically occult noncalcified breast lesions. AJR 1988;151:43-47 3)Meyer JE, Lester SC, Frenna TH, White FV. Occult breast calcifications sampled with large-core biopsy: confirmation with radiography of the specimen. Radiography 1993;188:581-582
Table – 1. Crosstabulation of number of microcalcifications demonstrated by direct digital radiography system and digital specimen x-ray
Results Of the 67 specimans containing microcalcification, 44 of the specimens when imaged with the digital specimen x-ray system showed more than 20 microcalcifications as opposed to only 24 with the direct digital radiolgraphy system. This is shown to be significant with a p-value of 0.001. In two of the specimens where no calcification was demonstrated on the direct digital radiography system, the digital specimen x-ray system demonstrated <5 microcalcifications. Significant difference was also shown in the conspicuity of the lesions between the two systems with the lesions having greater conspicuity on the digital specimen x-ray system (p-value of 0.027)
Results The total number of specimens was 97. Of these specimens 67 contained microcalcification, 23 masses, 4 distortions and 3 masses with calcification.
Table – 3. Fisher exact test for number of microcalcifications seen
D
IGITAL
SPE
CIMEN
X-‐RAY
DIRECT DIGITAL RADIOGRAPHY SYSTEM
No count
<5 <10 <15 <20 >20 Total
< 5
2 2 0 0 0 0 4
<10 0 3 2 0 0 0 5
<15 0 5 4 1 0 0 10
<20 0 0 0 3 1 0 4
>20 0 0 1 11 8 24 44
Total 2 10 7 15 9 24 67
DIRECT DIGITAL MAMMOGRAPHY CONSPICUITY
DIGITA
L SPEC
IMEN
X-‐RA
Y CO
NSPICUITY
1 2 3 4 TOTAL
1 0 0 0 0 0
2 1 0 0 0 1
3 1 2 3 0 6
4 0 3 16 42 61
TOTAL 2 5 19 42 68
Microcalcifica>on
Not well seen Clearly visible total
Digital specimen x-‐ray 3 58 61
Direct Digital mammography
19 42 61
Fisher exact test P-‐value = 0.027
No. of Microcalcifica>on
Total Less than 20 More than 20
Digital specimen x-‐ray 23 44 67
Direct Digital mammography
43 24 67
Fisher exact test P-‐value = 0.0001
Significantly more microcalcification is demonstrated by the digital specimen x-ray system when compared with direct digital mammography. Conspicuity of lesions is also shown to be significantly better with digital specimen x-ray. This provides increased confidence that a representative sample has been obtained at biopsy. This potentially avoids the need to take further samples and can lead to increased diagnostic confidence at biopsy. In addition, a digital specimen imaging modality avoids delay in the performance of specimen mammography in a busy breast imaging department.
BioVision digital specimen radiography system from bioptics
Table – 4. Fisher exact test for conspicuity of lesions containing microcalcifications
Table – 2. Crosstabulation of conspicuity of lesions containing microcalcification
Fig -1. Soft tissue mass shown on DSRS
Fig – 2. Microcalcification shown on DSRS