Pam Harrison

April 10, 2013

VIENNA, Austria — A fully automated magnetic resonance imaging (MRI) system accurately measures breast density without the need for compression or the use of radiation, new research shows.

"Breast density increases the risk of breast cancer and breast cancer recurrence and reduces the sensitivity of mammography," said Katja Pinker-Domenig, MD, associate professor of radiology at the Medical University Vienna in Austria.

"Our fully automated MRI breast density measurement system allows for fast, reliable, and quantitative breast density measurements. It also confirmed higher breast densities in breast cancer patients than in healthy control subjects," she explained.

Dr. Pinker-Domenig and colleague Georg Wengert, also from the Medical University Vienna, described the novel breast density measurement system here at the European Congress of Radiology 2013.

The researchers compared images obtained with the novel MRI-based breast density measurement system and mammographic estimations of breast density in 43 premenopausal volunteers.

Two datasets were obtained using the fully automated system: one representing fatty tissue; the other representing glandular tissue.

The MRI-based system calculated the percentage of fatty and glandular tissue and the total volume of the breast. The mean MRI-based breast density measurement was approximately 26%, which correlated significantly with the mammographic breast density measurement (P < .0001).

However, quantitative MRI breast density readings were consistently lower than qualitative Breast Imaging-Reporting and Data System (BI-RADS) assessment on mammography.

"Mammographic breast density assessment tends to either over- or underestimate breast density, and there is significant interobserver variability," Dr. Wengert noted.

Mammography also requires the use of radiation and compression of the breast, which can be painful, he explained. In addition, a 2-dimensional assessment of a 3-dimentional organ does not allow for a true estimation of breast density.

MRI-breast density measurement allows investigators to obtain a 3-dimensional assessment of the breast, and without the need for either radiation or compression, Dr. Wengert explained.

3-Dimensional View

In a related presentation, Dr. Pinker-Domenig described MRI-breast density measurements obtained from 19 women with biopsy-proven breast cancer and 19 healthy control subjects. In both groups, mean age was 50 years.

"Fully automated quantitative MRI breast density measurements were successfully performed in both groups," Dr. Pinker-Domenig reported. The mean breast density for all women was 21.4%, but the mean percentage density was higher in breast cancer patients than in control subjects (24.0% vs 18.4%).

Breast density decreased gradually with age in both groups, Dr. Pinker-Domenig noted.

"These results are consistent with previous studies that have linked high breast density to breast cancer. They are also consistent with our understanding that breast density is a strong independent risk factor for breast cancer," she said.

"This is relevant because once we identify women at greater risk for breast cancer, we can follow them with different strategies — more frequent screening, different methods of screening, and more frequent MRI breast density screening because no radiation is involved," she said.

This is especially valuable because it has been shown that women at higher risk for breast cancer are more susceptible to the damaging effects of radiation.

This work is interesting because it shows that a qualitative measure of breast density is important if breast density is an independent risk factor for breast cancer, said session cochair Luca Carbonaro, MD, from IRCCS Policlinico San Donato Hospital in Milan, Italy, who was asked by Medscape Medical News to comment on the research.

"Up to now, there has been a lack of standardization in breast density assessments," Dr. Carbonaro said. "I believe that the use of a reproducible method to assess breast density can be the starting point from which to design homogeneous studies. The aim will be to give every woman a tailored screening program based on her age, family history, and breast density."

Dr. Wengert, Dr. Pinker-Domenig, and Dr. Carbonaro have disclosed no relevant financial relationships.

European Congress of Radiology (ECR) 2013: Abstracts B-562 and B-563. Presented March 9, 2013.