6th International Workshop on Breast Densitometry and Breast ...

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6 th <strong>International</strong> <strong>Workshop</strong> on Breast Densitometry
and Breast Cancer Risk Assessment
BACKGROUND PARENCHYMAL UPTAKE OF Tc-99m SESTAMIBI ON MOLECULAR
BREAST IMAGING IN WOMEN WITH DENSE BREASTS
Hruska CB 1 , Conners AL 1 , Jones KN 1 , Lingineni R 2 , Carter R 2 , Shah S 3 , Visscher D 3 , Rhodes DJ 4 ,
Vachon C 2
1 Departments of Radiology, 2 Health Sciences Research, 3 Laboratory Medicine and 4 Pathology, and
Medicine, Mayo Clinic, Rochester, MN
Background: While evaluating molecular breast imaging (MBI) for adjunct screening in women with
dense breasts, various presentations of background parenchymal uptake (BPU), or uptake of Tc-99m
sestamibi in normal fibroglandular tissue (FT), were observed. We describe the prevalence of BPU in
dense breasts and examine clinical and histologic risk factors associated with BPU.
ABSTRACTS
Methods: Screening MBI exams performed between April 2010 and March 2012 at Mayo Clinic in
women with dense breasts (BI-RADS D2 - scattered densities; D3 - heterogeneously dense, or D4 -
extremely dense) were reviewed. Participants with breast implants or cancer diagnosed at screening were
excluded. BPU intensity was subjectively categorized by two radiologists as photopenic (uptake in FT <
subcutaneous fat), mild (uptake in FT = fat), moderate (uptake in FT up to 2x fat), or marked (uptake in
FT > 2x fat). Association of BPU with age, BI-RADS mammographic density, percent density measured
by Cumulus, menopausal status, and use of hormonal medications was examined using Kruskal-Wallis
and Chi-Square analyses. To examine association of histological factors with BPU, prospective coreneedle
breast biopsy of 23 postmenopausal women was performed in regions of mammographically dense
tissue demonstrating either photopenic (18 women) or marked (5 women) BPU.
Results: In 1274 MBI exams, BPU was photopenic in 273 (21%), mild in 826 (65%), and moderate or
marked in 175 (14%). Significant differences in distribution of BPU were observed with age, BI-RADS
density, percent density, menopausal status, and postmenopausal hormone use (all p75% involuted).
Conclusion: Moderate/marked BPU occurred more often in denser breasts and in women who were
younger, pre- or perimenopausal, or using exogenous hormones. In each density category, substantial
proportions of both moderate/marked and photopenic BPU were observed, establishing that similarappearing
FT on mammography can demonstrate considerable differences in BPU on MBI.
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