Diffusion-weighted MR shows potential for clarifying breast lesions without contrast

An innovative, seven-minute MR scanning technique using no contrast has shown promise in ruling out malignancy—and thus averting unneeded biopsies—when deployed after regular screening mammography brings back troubling lesions.

The technique, diffusion-weighted imaging with background suppression MR mammography (DWIBS-MRM), had a negative predictive value of 92 percent in a prospective study of 50 women who had suspicious mammograms occasioning physician orders for biopsy.

The study is running ahead of print in Radiology.

Using DWIBS-MRM, lead author Sebastian Bickelhaupt, MD, a radiologist at the German Cancer Research Center in Heidelberg, and colleagues reached similar levels of accuracy as with two comparison techniques—full diagnostic workup with histopathologic findings and abbreviated contrast MR.

Along with the 92 percent negative predictive value, DWIBS-MRM had specificity of 94 percent and positive predictive value of 93 percent.

In addition to the quick scan time, it also had a reading time of less than 30 seconds. This largely owed to the use of maximum intensity projection (MIP), which allows the radiologist to interpret from one summary image without having to pore over multiple slices.

Of the 50 patients in the study, 24 had a malignancy. Most of these (21 or 87.5 percent) were invasive ductal carcinomain situ (DCIS). One was invasive lobular carcinoma.

The only cancers undetected by DWIBS-MRM were two at a very early stage of the disease, DCIS lesions related to pure clustered microcalcifications. The abbreviated MR with contrast missed these as well.

The authors concluded that, when used as a complement after the screening clarification procedure, DWIBS-MRM is highly accurate in ruling out malignancy in BI-RADS category 4 or 5 lesions detected on x-ray screening mammograms.

The 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,” Bickelhaupt said in prepared remarks. “This might help to reduce the number of invasive biopsies and the related anxiety in women who have suspicious findings at mammography.”