Beyond your mother's mammogram

MBI, tomosynthesis and ultrasound detect cancer in dense breast tissue

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March 28, 2014 | 9:26 pm

Just about everyone has heard about the traditional 2D mammogram.

These x-ray pictures of the breast are used as screening tools to check for breast cancer in women with no signs or symptoms of the disease and as diagnostic tools to check for breast cancer after a lump or other signs or symptom of the disease have been found.

The National Cancer Institute recommends that women age 40 or older have screening mammograms every year. But some women and their doctors may also want to pursue newer, additional screening and diagnostic technologies available locally, such as molecular breast imaging (MBI) and ultrasounds.

These tests are especially helpful for women with dense breast tissue — that is, breasts that have more glandular and supportive tissue than fat. That dense tissue can look white on a mammogram, making it difficult to detect breast cancer, which also appears white. High breast density also is linked to an increased risk of breast cancer.

But you can’t tell whether you have dense breast tissue just by how your breasts feel. You need a mammogram; the physician reading the mammogram can assess and report if your breasts are heterogeneously or extremely dense. It’s a good idea to ask year health care provider, and discuss further options if necessary, say local health professionals.

Molecular Breast Imaging (MBI)

Mercy Medical Center introduced Molecular Breast Imaging in Iowa in 2011, and UnityPoint Health — St. Luke’s Hospital began offering it the following year. It is one of several FDA-cleared technologies used for breast imaging as a complement to mammography. Others include ultrasound, MRI and tomosynthesis.

With MBI, the patient is given an injection in the arm of a short-lived radioactive isotope, the same used in cardiac imaging. This material accumulates more in tumor cells than it does in normal cells. Using a dual-head digital imaging system, tumors then show up as “hot spots” on the resulting image.

“MBI is a functional test. It can look through even the densest breast and tell us where there is tissue that is functioning out-of-the-ordinary,” says Dr. Laura Hemann, medical director of women’s imaging for Mercy Women’s Center and Radiology Consultants of Iowa. “In a mammogram, even one using tomosynthesis, we’re just looking at anatomy. So we’re looking at completely different things with the two tests.”

Medicare covers MBI, but most insurance does not. Out-of-pocket cost at Mercy is $538. The test is covered by the Especially for You Fund, a financial-assistance program for uninsured or underinsured people who live in or around Linn County and use accredited Cedar Rapids health care facilities.

“It’s not inexpensive, but it can be very beneficial … it’s a supplemental exam for women who have an increased risk, but not enough risk to be eligible for an annual MRI breast exam,” Hemann says. MRI — magnetic resonance imaging — is used as a screening test when women carry the BRCA1 or BRCA2 genes and have a family history of breast cancer. “It’s good for women to know what their options are.”

Breast tomosynthesis (3D mammography)

A traditional two-dimensional mammogram is comprised of several images of each breast, compressing a lot of information into one flat image.

Technology available at University of Iowa Hospitals and Clinics adds more dimension to that image — literally. Tomosynthesis, or three-dimensional mammography, takes multiple pictures of the breast, then pieces them together into a three-dimensional image that radiologists can manipulate.

“Instead of looking at two flat pictures, I can look at 50 or 60 images. I can look at the breast in slices, one millimeter at a time, like paging through a book. If my slice gets to a point in the breast where there’s a cancer, that’s all I see. I don’t have the tissue above or below it crowding it out,” says Dr. Laurie Fajardo, professor of radiology at University of Iowa Hospitals and Clinics. For that reason, the test is especially beneficial to women with breast dense tissue, or who are otherwise at higher risk for developing breast cancer.

From the patient’s perspective, the test is no different from a regular mammogram — though it does take slightly longer. A traditional mammogram takes about one-tenth of a second, versus two seconds for tomosynthesis. The machines also take a 2D mammogram. While the test exposes patients to more radiation than a traditional mammogram, it still falls below FDA limits and the dose a patient would receive from an MBI exam.

UIHC has five tomosynthesis machines — three in Iowa City and two at the Iowa River Landing clinic in Coralville. Doctors have been using the machines with patients for two years, and before that, Fajardo says, they “did a lot of the pivotal research on the design and how to get the best image quality.”

Most insurance does not cover 3D screening; those who choose the test currently have an additional $60 out-of-pocket fee tacked into the mammogram bill.

Automated Volume Breast Ultrasound Scanning (AVBS)

Later this fall, University of Iowa Health Care — Iowa River Landing in Coralville will become the first provider in the area to offer Automated Volume Breast Ultrasound Scanning as a supplemental ultrasound breast cancer screening tool for women with dense breasts.

“We’ll still need to do the mammogram, but an ultrasound lets you see the tissue a little differently. It’s very helpful in seeing breast masses,” Fajardo says. Ultrasound technology sees cancer as echo patterns of dark and gray, while dense breast tissue appears as white.

The patient lies on her back and the machine is placed gently on top of the breast; there is no breast compression involved. The system scans the breast systematically from three different positions, collecting thousands of images that can be used to create a three-dimensional ultrasound picture of each breast.

“It takes a little bit longer than tomosynthesis does, but there isn’t radiation, and there isn’t compression,” Fajardo says.

AVBS will likely be beneficial to women with breast implants as well as those who have dense breast tissue and have a moderate increased risk for breast cancer, but for whom insurance does not cover a breast MRI screening examination. Insurance covers this exam, and there is no additional charge to a patient who has supplemental AVBS screening in addition to a screening mammogram/tomosynthesis.

“It’s very exciting for me, as a more senior radiologist in breast imaging, to see the development of personalized medicine in the area of breast cancer screening,” Fajardo says. “There are now several breast cancer tools that can be tailored to a specific woman depending on her breast density, her lifetime risk for developing breast cancer and other issues specific to an individual, such as breast implants.”

This story originally appeared in the Oct. 6, 2013 Surviving Breast Cancer special section.

 

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