A technique that combines high-level magnetic resonance imaging (MRI) with a new spectroscopic method may result in an accurate, non-invasive way to make breast cancer diagnoses. In this technique, MRI is used to detect breast lumps, while spectroscopy measures molecules known to accumulate in cancer cells.

According to a study published in the journal Magnetic Resonance in Medicine, researchers at The Cancer Center at the University of Minnesota have developed a magnetic resonance spectroscopy (MRS) method that quantifies breast tissue levels of choline (tCho) compounds, which the study found to be elevated in malignant lesions. Previous investigations of the diagnostic utility of MRS did not quantify tCho levels in breast masses, which limited the ability to differentiate between benign and malignant lumps detected by MRI.

"We found tCho concentrations to be significantly higher in malignancies than in benign lumps and normal breast tissues using this quantitative method," said lead investigator Michael Garwood, Ph.D., professor of radiology and Cancer Center member. "Using high magnetic fields and this spectroscopic technique may produce a powerful way to diagnose breast cancer and to monitor its response to treatment. We hope this technique will eventually be used to avoid unnecessary biopsy."

The application of MRS to breast cancer has unique technical demands. The problem lies in the composition of the breast, whose irregular distribution of fatty and glandular tissue makes it difficult to establish reference points against which to measure tCho levels. This method accounts for these tissue variations, using water as a reference compound and a mathematical approach to help "fit" or see choline levels relative to other compounds. This technique also exploits the increased sensitivity of a high magnetic field MR scanner, available only at a few locations in the world, including the University of Minnesota's Center for Magnetic Resonance Research (CMRR).

So far the study has enrolled 105 subjects and measured tCho levels in normal breast tissue and in benign and malignant lesions. The study remains open to women who have a suspicious breast lump; however, MRI and MRS scanning must occur before a biopsy or surgery on the lump has been performed. To determine the accuracy of the test, tCho concentrations will be compared with the pathologic findings in the excised tissues.

SOURCES:
Magnetic Resonance in Medicine, online edition, November 21, 2003
University of Minnesota (http://www.umn.edu)