(American Roentgen Ray Society) -- MR imaging can find breast cancers that mammography has missed and should be considered for screening high-risk women, a new study suggests. The study is the largest to date done in the U.S.

Researchers at Memorial Sloan Kettering Cancer Center in New York reviewed the records of 367 women who had their first MR imaging screening examination. The examination was done using contrast media. All of the women were considered to be at high risk of developing breast cancer, says Elizabeth Morris, MD, lead author of the study. High risk patients include those that have previously been treated for breast cancer, have a first degree relative with breast cancer, have the BRCA 1 or 2 gene, or have been diagnosed with a benign lesion that can be a precursor to breast cancer, says Dr. Morris.

Based on the MR results, 59 women underwent a biopsy. "Biopsy revealed cancer that was not previously seen on a mammogram or felt on a physical examination in 17 (24%) of these women," says Dr. Morris. "Biopsy revealed high-risk lesions in 13 women and benign disease in the remaining group of women, Dr. Morris adds.

More than half of the MR detected cancers were ductal carcinoma in-situ (DCIS), says Dr. Morris. "These were early cancer, pre-invasive cancers," she says.

"There is a lot of interest in MR screening for breast cancer, particularly for high risk women because we want to find a supplemental test for mammography. While our study indicates that MR is a very valuable tool, more patients need to be studied and cost analyses need to be done before it is made universally available," she says.

Dr. Morris presented her study on May 6, during the American Roentgen Ray Society Annual Meeting in San Diego, CA.