Abbreviated MR May Serve as Added Breast Cancer Screening Tool
Critics of breast MR imaging have focused on its high cost, lengthy duration, high false-positive rates and the tendency of the exam to detect indolent breast cancers. But what if breast MR imaging could be performed faster and cheaper, yet still be able to detect biologically significant breast cancers?
By Mike Bassett
In a study presented Monday at RSNA 2014, Laura Heacock, M.D., Linda Moy, M.D., and colleagues at New York University Langone Medical Center, determined that abridged breast MR imaging can significantly reduce acquisition times while detecting biologically significant cancers.
"MRI has the highest sensitivity for the detection of invasive breast carcinoma and ductal carcinoma in situ [DCIS]," said Dr. Heacock in her presentation. "Critics of this exam have argued that it leads to the overdiagnosis and overtreatment of more indolent tumors. However, the functional information that a breast MRI can provide can help us detect more aggressive lesions."
Dr. Heacock said an abridged MR protocol is comparable to the current mammography model in which a short screening exam can be performed and the patient recalled as necessary for a full exam. "The potential benefits of such an approach," she said, "include wider availability due to the decreased scan time and cost of the exam, decreased radiologists interpretation time, and increased patient comfort and tolerability."
According to Dr. Moy, the idea behind an abridged MR imaging protocol was introduced by Christiane Kuhl, M.D., of the Department of Diagnostic and Interventional Radiology at the University of Aachen in Germany. In a study published earlier this year in the Journal of Clinical Oncology, Dr. Kuhl and her colleagues demonstrated that an abbreviated MR imaging protocol for breast cancer resulted in an exam that took just three minutes, and was more accurate than digital mammography.
"I was intrigued by this because it really changes the whole paradigm of how we can detect breast cancer," Dr. Moy said, adding that abbreviated MR imaging could address the biggest barriers to an increased use of breast MR imaging—cost and time factors.
"If we have short version MR imaging and can get valuable information from it, it may lead to a more widespread use of MR imaging as a supplement for women who may be high risk or have dense breast tissue," she said. "We're lucky that we have many new imaging modalities—like breast ultrasound and tomosynthesis—to detect breast cancer, but it's important that MR imaging becomes more widespread because it has the highest sensitivity of these modalities."
Abridged MR Imaging Yields 98 Percent Specificity
Last year at RSNA 2013, Dr. Moy and colleagues presented a study in which they reviewed 100 breast MR imaging exams with an abridged protocol and found that they were successful in detecting known cancers.
In this study, Drs. Moy, Heacock and their colleagues sought to determine how an abridged MR protocol with one post-contrast (and subtracted) sequence at 90 seconds performed at identifying cancers considered to be biologically significant.
"Our thought was that if we could detect these invasive cancers, particularly those that are going to be an intermediate grade or higher, these are the cancers that are going to metastasize," Dr. Moy said.
Researchers retrospectively reviewed 103 women with 180 findings who underwent a breast MR imaging exam and determined that the abridged MR imaging "works very well," Dr. Moy said. "All of the cancers that were high grade were detected."
Of six cancers that were missed, two were intermediate-grade invasive cancers, she said, "and that's where we need to improve." Another four were lower-grade ductal carcinoma in situ, which Dr. Moy said would likely be classified as indolent tumors.
The abridged breast MR imaging protocol yielded 98 percent sensitivity for invasive cancers, 83 percent sensitivity for DCIS and increased specificity compared to routine breast MR exams, reported Dr. Heacock. Therefore, "the abbreviated MR exam may potentially reduce overdiagnosis by preferentially detecting biologically significant breast cancers."
"We think an abbreviated MR can really serve as an additional screening tool, not just for women at very high risk, but maybe for women who are low to moderate risk or perhaps even women with dense breast tissue," Dr. Moy said. "This can be a supplement to screening mammography, just like ultrasound and tomosynthesis."