MRI technique beats breast ultrasound at supplemental screening

Diffusion-weighted MRI (DWI) may soon command broader consideration than it’s been getting as a supplemental breast-screening tool. The modality not only finds many breast cancers that don’t show up on mammograms but also outperformed supplemental breast ultrasound in a study published online Oct. 28 in Clinical Imaging.

Nita Amornsiripanitch, MD, of the University of Massachusetts and colleagues retrospectively evaluated DWI vs. ultrasound for showing 60 mammographically occult breast cancers that were initially detected on contrast-enhanced MRI and underwent pre-biopsy targeted ultrasound.

The team found that more known cancers were visible on DWI than ultrasound (78 percent vs. 63 percent; p = 0.049).

A little over half the cancers were visible on both and 12 percent were not visible on either.

Visibility differences were more significant in larger lesions (92 percent vs. 68 percent), the authors report.

Commenting on DWI versus contrast-enhanced MRI, the authors note the safety concerns, added costs and lengthy exam times that necessarily accompany the use of contrast agents.

They also note DWI’s short scan time, “which may render the modality more comparable in cost and exam length to handheld whole breast ultrasound.”

“Our study suggests that DWI may detect more mammographically occult breast cancers than ultrasound, supporting the potential role of DWI as a safer and more cost-effective supplemental screening tool as an alternate to contrast-enhanced MRI that warrants further investigation,” they conclude.

DWI uses the diffusion of water molecules to generate contrast effects in MR images.