Objective measurement of breast density, a marker of breast cancer risk, using fully automated radiation- and compression-free MRI.

Abstract

11088 Background: Women may have contraindications to mammography (MG) or simply refuse the test due to subjective reservations usually concerning compression and/or radiation. Other than the detection of suspicious findings these women do not have standardized information concerning their breast density (BD), one of the strongest independent predictors of breast cancer (BC) risk. We developed a fully-automated quantitative magnetic resonance imaging (MRI) based BD measurement system, provided correlation to MG BD estimation and compared BD in BC patients and age-matched healthy controls. Methods: In this IRB-approved prospective study 35 healthy women and 19 BC patients age-matched to one of the healthy controls were included. BD for healthy women and BC patients was assessed using a) subjective qualitative radiologist´s review allocating 1 of 4 ACR BIRADS BD categories, b) Cumulus, a MG based semi-automatic method and c) a radiation- and compression-free MRI measurements system, which automatically calculates volume of breast (cm3), % of fatty tissue and % of glandular tissue. Descriptive statistics were used to define the typical range of quantitative MRI BD readings corresponding to the qualitative four ACR BIRADS BD categories. Áppropriate statistical tests were used to compare mean values of method b) and c) and BD readings of cancers and controls. Results: % MRI BD correlated well with % MG BD (r = 0.83; P < 0.0001). MRI BD measurements ranged from 1.7% to 61.9% (mean 29.05%). MG BD measurements ranged from 5.42% to 74.33% (mean 40.23%). Equivalent values were found with MRI BD readings of 0-7.2%, 7.3-26%, 26.1-39.6% and >39.7% respectively for each of the four ACR BIRADS BD categories. Mean BD (%) was higher in BC patients than in healthy controls: 24% (SD 16.9%) vs. 18.4% (16.6). Conclusions: MRI BD measurement strongly correlates with MG based BD readings. The data suggest that objective, radiation- and compression-free MRI BD measurement is a convenient alternative to MG for assessment of BD. MRI BD measurement confirms higher breast density in BC patients compared to healthy women. The data is entirely consistent with the fact that BD is a strong independent risk factor for BC.