Bigger magnets mean finding more cancer, sooner


Emma Carew

By now, doctors and researchers would hope that everyone knows mammograms help catch breast cancer.

But mammograms can miss up to 25 percent of cancers in young women because their breast tissue is too dense.

University researchers at the Center for Magnetic Resonance Research have been working to develop breast magnetic resonance images and magnetic resonance spectroscopy, tools to help doctors diagnose cancer in high-risk cases and younger women.

The technology for breast MRIs isn’t new, although they have done research on high field magnets, which produce higher quality images, the center’s Pat Bolan said.

Breast MRIs identify tumors by analyzing blood flow. While mammograms find calcifications in the breast, MRIs identify areas of abnormal vascularity, he said.

The newest developments have come in spectroscopy, he said.

Spectroscopy uses a combination of magnetic fields and radio waves to track chemicals in a tumor, Bolan said, so they can often tell without a biopsy if a tumor is benign or malignant.

MRIs are used for patients who have an identified increased risk of developing breast cancer, Dr. Michael Nelson said.

The average woman has about a 12 percent risk of developing breast cancer in her life, Nelson said.

If a woman’s risk has been identified at 20 to 25 percent or higher – such as a family history of breast cancer or a confirmed mutation of either BRCA gene for instance – she might be considered for regular MRI screening, he said.

In some cases, a contrast agent, usually gadolinium, is injected and areas that would have been missed by a mammogram or PET scan will light up on the MRI, Nelson said.

The center is unique to Minnesota, he said, the only of its kind in the world.

Using the MRI technology, cancerous tumors as small as 1 mm to 2 mm can be seen, Nelson said. The old technology only found tumors 2 cm and larger.

Another development at the center involves spectroscopy, Bolan said, a process that generates data that quantifies the chemicals within a tumor.

Using spectroscopy, it is possible to track the levels of the chemical choline, he said.

If a patient is receiving chemotherapy, spectroscopy can prove right away whether the treatment is working.

It the chemotherapy works, the levels of choline will decrease, generally within the first 24 to 48 hours, Bolan said.

This development is important for clinical trials of new drugs, he said.

Rather than wait through multiple rounds of chemotherapy and using imaging to see if the tumor shrinks, doctors can see how tumors will react to the drugs right away by measuring the levels of choline.