Diffusion-Weighted MRI Technique Cuts Breast Biopsy Requirements

An abbreviated magnetic resonance imaging (MRI) protocol could reduce unnecessary breast biopsies by providing additional information on suspicious X-ray screening mammography findings, according to a new study.

Researchers at the German Cancer Research Center (DKFZ; Heidelberg, Germany), University Hospital Heidelberg (Germany), and other institutions conducted a study to evaluate the ability of an abbreviated MRI protocol consisting of maximum intensity projections (MIPs) from diffusion-weighted imaging with background suppression (DWIBS) and unenhanced morphologic sequences to help predict the likelihood of malignancy on suspicious screening X-ray mammograms, as compared with an abbreviated contrast material-enhanced MRI protocol and a full diagnostic breast MRI protocol.

To do so, 50 women (mean age 57.1 years), who gave informed consent and who had suspicious screening mammograms and an indication for biopsy participated in a prospective study from September 2014 to January 2015. Before biopsy, a full diagnostic contrast-enhanced MRI was performed that included DWIBS. Two abbreviated protocols based on MIPs were evaluated; the first showed the shape and appearance of the lesion; the second displayed its biophysiological properties with DWIBS, a technique that works by assessing the diffusion of water molecules through tissue, since areas of restricted diffusion may indicate malignancy.

The results showed that 25 of the 50 participants had a breast carcinoma. DWIBS achieved a comparable accuracy to that of the full diagnostic and the abbreviated contrast-enhanced MRI protocols, yielding an excellent negative predictive value of 92%. Only pure microcalcification related ductal carcinoma in-situ (DCIS) without solid tumor—a very early stage of breast cancer—was not detected by any of the MRI techniques. The study was published early online on September 11, 2015, in Radiology.

“If the preliminary findings are confirmed, this approach could have a high potential to be used as an adjunct in the clarification process of unclear lesions on X-ray mammography in breast cancer screening,” said lead author Sebastian Bickelhaupt, MD, a radiologist at DKFZ. “This might help to reduce the number of invasive biopsies and the related anxiety in women who have suspicious findings at mammography.”

DWIBS MRI holds several advantages; the images can be obtained in less than seven minutes, compared with more than 30 minutes for a full breast MRI protocol; and the mean reading time using the unenhanced DWIBS method is less than 30 seconds thanks to MIPS, a technique that allows lesion assessment by reading one summation image instead of multiple single-slice images. The technique however, is in its early stages, and as such is not intended as a standalone screening modality but as an adjunct to X-ray mammography and tomosynthesis.

Related Links:
German Cancer Research Center
University Hospital Heidelberg