The American Cancer Society recently issued new recommendations for women with a higher risk of developing breast cancer, including those with a family history of breast or ovarian cancer, and those who may carry genetic mutations (BRCA1 or BRCA2) that make them more likely to develop the disease.
Specifically, it recommends the use of screening MRI as an alternative to conventional mammography for women at higher risk, because the former is more sensitive and can detect hidden tumors that might otherwise escape notice.
However, according to UNLV's Dr. Phillip Patton, the lead investigator on the project, MRI is so sensitive that it reveals even non-cancerous suspicious growths in the breasts, providing insufficient specifics about whether such growths are malignant. This in turn leads to many unnecessary biopsies and additional scans, not to mention heightened anxiety. In this new approach, any suspect lesions can be imaged with MRS, with no need for an invasive biopsy. Spectroscopy can be used to test for any number of chemical compounds. In breast MRS, it is useful in measuring the amount of a metabolite called choline in suspect lesions. In most cases, elevated levels of choline are a strong indicator of malignancy (cancer).
Thus far, the UNLV researchers have done MR spectroscopy on healthy patients without breast cancer as proof of principle. As expected, choline levels were low. The next step is to image patients with breast cancer to confirm that MRS can be used to detect the telltale higher choline levels. The UNLV study is being conducted in conjunction with Spring Valley Nevada Imaging Centers Amigenics and Philips Medical Systems. The study is the first step in what Patton and colleagues hopes will be a series of clinical studies on the efficacy of MRS to distinguish between normal and cancerous tissue, including comparisons to other magnetic field strengths for both MRI and MRS.
Patton and graduate student Rob Etnire are using a 3.0 T MR spectrometer, the highest magnetic strength allowable for clinical use by the FDA. There have been prior similar published studies, but those used 1.5 T or 4.0 T spectrometers; Patton's team is the first to publish results using the 3.0 T instrument. "In theory, the higher magnetic strength gives more signal to noise for the same imaging time," explains Etnire "Thus, it will either improve the quality of the image, or shorten the time to obtain a certain quality image."