Quantification Of Breast Density Research Articles

Magnetic Resonance Imaging quantification of breast density in BRCA carriers following gonadotropin releasing hormone agonist (GnRHA)-based hormonal chemoprevention

1506 Background: Breast tissue density limits the usefulness of mammography as a surveillance tool in young women. Breast Magnetic Resonance Imaging (MRI) provides high tissue contrast and three-dimensional structural information not impaired by high breast density. We developed a volumetric “MR density” measure of breast structural composition that may be complementary to mammographic breast density. We tested this MR density measure in unaffected women with known high risk of breast cancer due to a BRCA gene mutation (or empiric risk > 30% lifetime), who were recruited in a phase II trial to study the effects of a hormonal chemoprevention regimen. Methods: Nine premenopausal high-risk women age 21 to 48 were treated with intranasal GnRHA (deslorelin), low-dose estradiol, and testosterone daily for 10 months. All patients underwent one contrast-enhanced breast MRI exam before and after treatment. We measured MR density as the ratio of fibroglandular tissue volume to total volume of the breast, at both time points. Our technique involved the semi-automated delineation of the breast and the automated segmentation of fibroglandular from adipose tissue. An “MR index” was also defined to quantify partial voluming effects due to the presence of adipose/fibroglandular edges in the MR data. Results: Eight out of nine patients showed a reduction in MR density (p = 0.026) with treatment. Three patients had less than 5% MR density at baseline, making it difficult to quantitate a change with treatment. All of the remaining six patients had reduced MR density after treatment (mean reduction 35.5%; p = 0.035). Conclusions: We have demonstrated the use of breast MR density as a robust volumetric quantitative measure of breast tissue composition. Our findings suggest that MR could be used to measure hormonal chemoprevention effects in BRCA carriers. [Table: see text]

Quantification of breast density with dual energy mammography: A simulation study

Breast density, the percentage of glandular breast tissue, has been identified as an important yet underutilized risk factor in the development of breast cancer. A quantitative method to measure breast density with dual energy imaging was investigated using a computer simulation model. Two configurations to measure breast density were evaluated: the usage of monoenergetic beams and an ideal detector, and the usage of polyenergetic beams with spectra from a tungsten anode x-ray tube with a detector modeled after a digital mammography system. The simulation model calculated the mean glandular dose necessary to quantify the variability of breast density to within 1/3%. The breast was modeled as a semicircle 10 cm in radius with equal homogenous thicknesses of adipose and glandular tissues. Breast thicknesses were considered in the range of 2-10 cm and energies in the range of 10-150 keV for the two monoenergetic beams, and 20-150 kVp for spectra with a tungsten anode x-ray tube. For a 4.2 cm breast thickness, the required mean glandular doses were 0.183 microGy for two monoenergetic beams at 19 and 71 keV, and 9.85 microGy for two polyenergetic spectra from a tungsten anode at 32 and 96 kVp with beam filtrations of 50 microm Rh and 300 microm Cu for the low and high energy beams, respectively. The results suggest that for either configuration, breast density can be precisely measured with dual energy imaging requiring only a small amount of additional dose to the breast. The possibility of using a standard screening mammogram as the low energy image is also discussed.

TH‐C‐332‐05: Quantification of Breast Density with Dual Energy Mammography

Purpose: To investigate a quantitative method for measuring breast density (the percentage of glandular breast tissue) with dual energy mammography using a dual exposure / dual kVp technique. Method and Materials: An analytical simulation model was developed to determine the mean glandular dose required to quantify breast density to within an accuracy of 1%. The simulation considered stochastic x‐ray and detector noise sources in a dual energy breast density image. The breast was modeled as a semicircle 10 cm in radius with homogenous equal thicknesses of adipose and glandular tissues. Monoenergetic beams were simulated with an ideal detector and polyenergetic spectra were simulated with an energy integrating detector modeled after an existing clinical system. A surrogate breast phantom was constructed to simulate a range of breast densities from 0 to 100%. The phantom was imaged using a full field digital mammography system at 25 kVp and 39 kVp with an additional 2 mm Al filter added to the high energy image. Dual energy images were generated with a non linear basis decomposition algorithm to yield image thickness maps of glandular and adipose tissue. Breast density was quantified using the dual energy images. Results: For a 4.2 cm breast of 50% density, optimal energies determined from simulation, for monoenergetic beams and an ideal detector, were 19 keV and 71 keV. For an energy integrating detector and polyenergetic spectra, optimal energies were 20 and 69 kVp. The estimated required dose for either technique was less than 0.1 mGy. For dual energy images, the known (K) and measured (M) breast densities were related by M = 1.007K − 0.006 (r = 0.999). RMS error for all densities was calculated to be less than 2% of the mean density. Conclusion: The results suggest that breast density can be accurately measured with dual energy mammography.

Neutral effect of ultra-low-dose continuous combined estradiol and norethisterone acetate on mammographic breast density

Objective To compare the effects of two different ultra-low doses of continuous combined hormone therapy and placebo on mammographic breast density in postmenopausal women.Methods A subpopulation of 255 postmenopausal women from the CHOICE trial were randomly assigned to 0.5 mg 17β-estradiol (E2) + 0.25 mg norethisterone acetate (NETA), 0.5 mg E2 + 0.1 mg NETA, or placebo. Women using hormone replacement therapy (HRT) up to 2 months prior to the study were excluded; 154 women fulfilled the inclusion criteria. Mammograms were performed at baseline and after 6 months. Breast density was evaluated by visual classification scales and a computer-assisted digitized technique.Results No significant differences were detected between the active treatment groups and the placebo group in the digitized quantification. The mean baseline values for density around 20% were unchanged after 6 months. Also, visual classifications showed no increase in breast density in any study group.Conclusion In contrast to currently available bleed-free regimens, the new ultra-low-dose combination of 0.5 mg E2 and 0.1 mg NETA seems to have very little or even a neutral effect on the breast. Both digitized quantification and visual assessment of breast density were unchanged after 6 months. Larger prospective studies should be performed to confirm this new finding.