Dynamic Contrast-Enhanced MRI Scanning May Reduce Breast Biopsies

Water diffusion measurements coupled with magnetic resonance imaging (MRI) could decrease false-positive breast cancer findings and reduce preventable biopsies.

Researchers reported that the technique also could improve patient management by distinguishing high-risk lesions requiring further workup from other nonmalignant subtypes. The study’s findings were reported in online October 2, 2012, in the journal Radiology. Dynamic contrast-enhanced MRI (DCE-MRI) has recently become a practical approach in breast cancer identification and staging. One of its chief restrictions is a substantial number of false-positive findings that require biopsies.

“Many benign lesions demonstrate enhancement on DCE-MRI,” said Savannah C. Partridge, PhD, research associate professor at the University of Washington, Seattle Cancer Care Alliance (Seattle, WA, USA). “We need another means for differentiating benign lesions from malignancies.”

One possible solution is diffusion-weighted imaging (DWI), an MRI application that calculates the apparent diffusion coefficient (ADC)--a gauge of how water moves through tissue. “DWI has been used mostly in neurological applications, but it’s been studied more recently in breast imaging,” Dr. Partridge stated. “It only adds a couple of minutes to the MRI exam and does not require additional contrast or any extra hardware.”

Research has shown that DWI is valuable for distinguishing between benign and malignant breast lesions. Normal breast tissue has a high ADC because water moves through it comparatively unrestricted, whereas most tumors have a lower ADC because their cells are more tightly crammed and restrict water motion. However, considerable overlap exists between the ADC values of nonmalignant lesions and breast malignancies, and little is known about the ADC values of specific subtypes of nonmalignant lesions.

Dr. Partridge and colleagues assessed the DWI characteristics of nonmalignant lesions in 165 women. Based on ADC values above an earlier determined diagnostic threshold, DWI effectively characterized 46% of nonmalignant breast lesions identified as false-positive findings on DCE-MRI as benign.

“We were excited to see the number of false-positives that could be reduced through this approach,” Dr. Partridge noted. “DWI gives us extra microstructural information to distinguish among lesions. We can use ADC values to draw a cutoff above which we might not need to do a biopsy.”

The investigators are planning a multicenter trial to validate the findings and determine how to best to incorporate ADC measures into clinical breast MRI interpretations. “We are very motivated to translate this promising technology to a clinically useful breast imaging tool,” Dr. Partridge concluded.

Related Links:
University of Washington, Seattle Cancer Care Alliance