Magnetic resonance imaging (MRI) has emerged as a powerful new tool that can be used as a complement to mammography and ultrasound for breast cancer screening of certain women, particularly those at high risk for the disease, according to Anne Hoyt, M.D., radiologist at UCLA’s Iris Cantor Center for Breast Imaging.
“Because of the increasing sensitivity and specificity of contrast-enhanced breast MRI over the last decade, we are using this exam more frequently,” Dr. Hoyt says.

MRI offers certain advantages over mammography, she explains. “One of the biggest limitations of mammography is that dense breast tissue decreases the test’s sensitivity — the likelihood of finding breast cancer when it is present,” Dr. Hoyt notes. “The sensitivity of MRI isn’t affected by the density of the breast.”

She stresses that there are also limitations to MRI. Mammography is better at detecting some cases of ductal carcinoma in situ, the early form of breast cancer still confined to the milk duct. MRI also comes with a risk of a “false positive” — identification of a noncancerous, incidental finding in the breast that requires further investigation or biopsy — a risk patients need to understand prior to undergoing the test, Dr. Hoyt says. MRI is significantly more costly than mammography and/or ultrasound. Finally, a high-quality MRI exam is essential and requires technical expertise, expert interpretation and the ability of the facility performing it to do an MRI-guided biopsy if necessary.

“For these reasons, it is very important that MRI be performed only when appropriate,” Dr. Hoyt says. “MRI is a very powerful tool, but understanding its limitations is important. It is not appropriate for all women, and even for those who should receive it, MRI should always be performed in conjunction with an annual mammography.

Women's Imaging Services

A new Santa Monica-UCLA Women’s Imaging Center opens this September in Santa Monica, providing a warm, calm and private setting for all imaging needs for women.

UCLA’s Iris Cantor Center for Breast Imaging, located in Westwood, is renowned for its groundbreaking contributions to breast imaging. For an appointment at either facility, call (310) 301-6800.