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Taking aim at breast cancer

MRI-guided biopsies now available to aid diagnosis

When a subtle but suspicious spot was picked up during an MRI breast scan at Community Hospital in the past, the patient had to travel to Stanford University Medical Center for an MRI-guided biopsy to learn whether the lesion was cancer. No more. The Community Imaging Center at Ryan Ranch has added new technology - the first of its kind in Monterey County - that enables doctors to do the MRI-guided tissue sampling on-site. That advance has streamlined the diagnostic process, enabling radiologists to hone in on areas that are otherwise difficult, even impossible, to target.

"The new equipment has made it possible to perform an MRI-guided biopsy of abnormalities found only through MRI," says Dr. Susan Roux, breast radiologist and medical director of Community Hospital's Breast Care Center.

Mammograms and ultrasounds are on the frontline for detecting breast cancer, but magnetic resonance imaging scans are increasingly being used for women with an especially high risk of breast cancer or who have already been diagnosed.

MRI uses the power of computers and magnetic fields, rather than X-rays, to noninvasively capture images of the human body. Highly detailed images of the breast are obtained before and after the injection of a special contrast agent.

"The injected contrast," Roux says, "makes the cancers appear as bright areas in the breasts. These bright spots often are in areas of the breast that appeared normal on mammogram or ultrasound. Even on a recheck evaluation of the breasts knowing where the MRI was abnormal, the mammogram and ultrasound are normal."

A 2003 study published in the peer-reviewed journal Radiology reported that up to 14 percent of malignant lesions in the breast are detectable only by MRI.

Last year, the American Cancer Society began recommending annual mammograms plus MRIs for women who meet certain high-risk conditions, including a genetic predisposition to the disease. Together, they give doctors a better chance of finding breast cancer early, when it is easier to treat and the chance of survival is greatest, the society said.

In many cases where lesions were found through mammogram or ultrasound, MRI can give an even clearer picture of the extent of the disease, Roux says.

"Approximately 25 percent to 35 percent of the time, the patient has much more cancer than was demonstrated by the other two tests, and the surgeons and oncologists change their treatment recommendations after seeing the MRI," Roux says.

"If a lesion is picked up on MRI, we then use the MRI to triangulate the position of the finding, then take extra mammogram and ultrasound views of the area," Roux says. "If they are all normal, then MRI is the only technology that can find it, and the only technology that can guide our needle for the biopsy."

An MRI-guided biopsy uses the images and computer analysis to locate the lesion, plot its coordinates, and aim the biopsy needle to take a tissue sample. As the last step, a tiny marker - a piece of metal about the size of a comma - is placed in the biopsied area so that it shows up on future mammograms for monitoring.

The procedure is less invasive than surgical biopsy, requires only a local anesthetic, leaves little or no scarring, and can be performed in less than an hour.

Roux and two other Community Hospital radiologists, Dr. Kristine Leatherberry and Dr. Amy Defatta, read the MRIs and do the biopsies. All three are board-certified radiologists with additional fellowship training in breast imaging and intervention. This year, Roux is celebrating her 20th year as a breast imaging specialist.

"We are doing MRI on about 30 percent to 40 percent of our cancer patients as part of their initial workup," Roux says. "We will be doing follow-up on some cancer patients whose cancer was difficult to see. MRI is a wonderful way to follow them in the future."
In addition to the new biopsy service, Community Hospital is now able to do bilateral MRIs. Using new software, radiologists are able to make images of both breasts at one time. In the past, two visits were required.

"We are committed to providing the latest technology for our community," says Eric LoMonaco, director of Radiology Services. "These technologies lead to the most accurate diagnostic results, which then allow us to provide the best care possible.