New MRI Technique Could Mean Fewer Breast Biopsies in High-Risk Women

The universal technology will give radiologists greater confidence in visually categorizing a lesion as malignant or benign.

The American Cancer Society (Atlanta, GA, USA) recommends that women with certain breast cancer risk factors including inherited genetic mutations, family, or personal history of breast cancer, or previous radiation therapy to the chest receive a yearly screening in addition to their yearly mammogram.

During a breast MRI, which lasts about 30 minutes, the technician injects a contrast agent into a vein in the patient's arm. Over time, the contrast agent flows throughout the body, including the breasts. Because they are growing quickly, cancerous lesions frequently have immature vasculature, and the contrast agent flows in and "leaks” out rapidly. On the other hand, benign lesions show more gradual in and out flow.

"The tricky ones are the ones that enhance quickly and then fall off more slowly,” said Dr. Wally Block, a University of Wisconsin-Madison (UW-Madison; USA) associate professor of biomedical engineering and medical physics. "Many of these lesions turn out to be difficult to classify and lead to biopsy.”

However, it turns out that with the right sort of MRI scan, radiologists can visually identify a cancerous lesion based on characteristics about its shape. For example, breaks or interruptions in a lesion can indicate a benign fibroadenoma. Lumps with smooth edges often are benign, while those with jagged edges can signal cancer.

To generate the kind of precise, three-dimensional (3D) images necessary for such a diagnosis, Dr. Block, UW-Madison radiology associate professor Dr. Fred Kelcz, and graduate student Catherine Moran are capitalizing on their unique MRI data-acquisition method.

An MR image is made up of thousands of smaller pieces of data. The traditional data-acquisition method gathers that information slowly, and it is designed to be viewed from a single imaging plane. "What people do now is they compromise,” said Dr. Block. "They don't get resolution in the other planes to make it a reasonable scan time. We found a way around that.”

With the team's powerful technique, an MRI machine acquires data radially and generates a high-resolution, 3D image that radiologists can turn, slice, and view from many perspectives enabling them to evaluate a lesion's physical characteristics more carefully. Machines equipped with the technique also acquire more data in less time.

Moreover, the method also makes it possible for radiologists to view fat images and water images separately, which is particularly useful because fat composes a large portion of the breast. "Rarely is disease associated with fat,” noted Dr. Block. "Most of the time radiologists are concentrating on water images, but sometimes our fat images of the breast are also useful. The boundaries of a lesion often stand out very clearly when embedded in fat.”

The investigators currently are collecting data on the efficacy of the technique. They have tested the method on 20 patients at the University of Wisconsin Hospital and have shared it with colleagues at the University of Toronto (Canada) for additional assessment. They also are working with Michigan State University researchers to test the technique.

Collaborating with Dr. Scott Reeder, a UW-Madison assistant professor of biomedical engineering and radiology, Dr. Block and colleagues also are fine-tuning ways to image both breasts simultaneously a development that could decrease scan time and free valuable MRI space for additional patients. "If you have a screening procedure that you want people to participate in regularly, you want to make it convenient for them,” concluded Dr. Block.

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