Stereo” Mammography

Stereoscopic digital mammography, a new diagnostic technique capable of producing three-dimensional, in-depth views of breast tissue, could significantly reduce the number of women who are recalled for additional tests following routine screening mammography.

"Standard mammography is one of the most difficult radiographic exams to interpret," said David J. Getty, Ph.D., division scientist at BBN Technologies of Cambridge, Mass. "In a two-dimensional image of the breast, subtle lesions may be masked by underlying or overlying normal tissue and thus be missed, and normal tissue scattered at different depths can align to mimic a lesion, leading to false-positive detections."

Stereoscopic digital mammography consists of two digital x-ray images of the breast acquired from two different points of view separated by about eight degrees. When the images are viewed on a stereo display workstation, the radiologist is able to see the internal structure of the breast in three dimensions. In the ongoing clinical trial, researchers use a full-field digital mammography unit modified to take stereo pairs of images. The workstation enables the mammographer to fuse the stereo image pair and to view the breast in depth.

"Stereo viewing is the only way to see the structure within the breast volume in true depth," said Dr. Getty, who has been working on the development of the technology over the past 12 years.

Scintimammography

Scintimammography, also known as nuclear medicine breast imaging, is an examination that may be used to investigate a breast abnormality that has been discovered on mammography. Scintimammography is also known as Breast Specific Gamma Imaging (BSGI).

Nuclear medicine is a branch of medical imaging that uses small amounts of radioactive material to diagnose and determine the severity of or treat a variety of diseases, including many types of cancers, heart disease, gastrointestinal, endocrine, neurological disorders and other abnormalities within the body. Because nuclear medicine procedures are able to pinpoint molecular activity within the body, they offer the potential to identify disease in its earliest stages as well as a patient’s immediate response to therapeutic interventions.

The procedure is noninvasive and involves the injection of a radiotracer, or drug that emits radioactivity, into the patient. Because the radiotracer accumulates differently in different kinds of tissue, it can help physicians determine whether cancer could be present, thus helping determine whether a biopsy or additional follow-up is necessary.

After injection, the radiotracer eventually accumulates in the breast, where it gives off energy in the form of gamma rays. This energy is detected by a device called a gamma camera. The camera works with a computer to measure the amount of radiotracer absorbed by the body and to produce special pictures offering details on both the structure and function of organs and tissues.

What are the benefits vs. risks?

Benefits

• Scintimammography can reduce unnecessary invasive procedures by helping physicians determine whether a breast abnormality requires biopsy.
• The procedure is particularly helpful for patients who have dense breast tissue or breast implants.

Risks

• Because the doses of radiotracer administered are small, diagnostic nuclear medicine procedures result in low radiation exposure, acceptable for diagnostic exams. Thus, the radiation risk is very low compared with the potential benefits.
• Nuclear medicine diagnostic procedures have been used for more than five decades, and there are no known long-term adverse effects from such low-dose exposure.
• The risks of the treatment are always weighed against the potential benefits for nuclear medicine therapeutic procedures. You will be informed of all significant risks prior to the treatment and have an opportunity to ask questions.
• Other imaging tests, such as mammography, ultrasound, and breast MRI, are lower in radiation dose than scintimammography and therefore may be more useful for most women. However, scintimammography may be an alternative for women that cannot undergo these examinations.
• Allergic reactions to radiopharmaceuticals may occur but are extremely rare and are usually mild. Nevertheless, you should inform the nuclear medicine personnel of any allergies you may have or other problems that may have occurred during a previous nuclear medicine exam.
• Injection of the radiotracer may cause slight pain and redness which should rapidly resolve.

Galactography (Ductography)

How is the procedure performed?

This examination is usually done on an outpatient basis.

The patient is seated or placed on her back with the breast exposed. The nipple is cleansed, and a tiny amount of fluid is squeezed from the nipple to identify the duct with the discharge. The milk duct may be dilated to permit a small catheter (a plastic, hollow tube) or blunt-tipped needle to be inserted into the milk duct. Occasionally a warm towel will be placed on the breast to help the milk duct become more visible and to allow easier access to the milk duct. A small amount of contrast material is then injected, and a mammogram is obtained. A second injection and mammogram may be performed.

You must hold very still and may be asked to keep from breathing for a few seconds while the x-ray picture is taken to reduce the possibility of a blurred image. The technologist will walk behind a wall or into the next room to activate the x-ray machine.

When the examination is complete, you will be asked to wait until the radiologist determines that all the necessary images have been obtained.

The procedure normally takes between 30 minutes and an hour.

MRI - Magnetic Resonance Imaging

The American Cancer Society has convened an expert panel to review new evidence regarding the use of Screening Breast Magnetic Resonance Imaging (MRI) for breast cancer. The expert panel reviewed this evidence and defined three levels of risk. These new recommendations are listed below. Please be aware that Screening Breast MRI does not replace mammography, but is considered an additional test. These recommendations are only for screening asymptomatic women, and do not apply to women who have symptoms or signs of breast cancer, including a lump or an abnormality on mammography or ultrasound.

1. MRI Breast Cancer Screening is recommended for women with a lifetime risk of 20 – 25% or greater for developing breast cancer. These include:

• Women with a breast cancer gene, BRCA1 or 2 (BReast CAncer 1 or 2).
• Women who are a first degree relative (parent, sibling, or child) of someone with a breast cancer gene.
• Women who have a lifetime risk of 20-25% based on a breast cancer prediction model determined primarily by family history, such as the BRCAPRO model.
• Radiation to the chest between age 10 and 30 years (such as is given for Hodgkin's Disease).
• Various rare syndromes that have a high incidence of breast cancer.

2. There is insufficient evidence to determine if MRI Breast Cancer Screening is useful or not for:

• Women who have a lifetime risk of 15-20% based on a breast cancer prediction model determined primarily by family history, such as the BRCAPRO model.
• Lobular carcinoma in situ (LCIS) or atypical lobular hyperplasia (ALH).
• Atypical ductal hyperplasia (ADH).
• Dense breasts on mammography.
• Women with a personal history of breast cancer, including ductal carcinoma in situ (DCIS).

3. MRI Breast Cancer Screening is not recommended for women who have a less than 15% lifetime risk of breast cancer. This includes most women.

Date: 2014-12-21; view: 1409