Women's Imaging

Breast Imaging and Procedures

Mammography

Mammography is a specific type of imaging that uses a low-dose x-ray system to examine breasts. A mammography exam, called a mammogram, is used to aid in the early detection and diagnosis of breast diseases in women.

An x-ray (radiograph) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Imaging with x-rays involves exposing a part of the body to a small dose of ionizing radiation to produce pictures of the inside of the body. X-rays are the oldest and most frequently used form of medical imaging.

Two recent advances in mammography include digital mammography and computer-aided detection.

Digital Mammography

Digital Mammography, also called full-field digital mammography (FFDM), is a mammography system in which the x-ray film is replaced by solid-state detectors that convert x-rays into electrical signals. These detectors are similar to those found in digital cameras. The electrical signals are used to produce images of the breast that can be seen on a computer screen or printed on special film similar to conventional mammograms. From the patient's point of view, having a digital mammogram is essentially the same as having a conventional film screen mammogram.

Computer-aided Detection (CAD)

Computer-Aided Detection systems use a digitized mammographic image that can be obtained from either a conventional film mammogram or a digitally acquired mammogram. The computer software then searches for abnormal areas of density, mass, or calcification that may indicate the presence of cancer. The CAD system highlights these areas on the images, alerting the radiologist to the need for further analysis.

Breast MRI

MRI of the breast is not a replacement for mammography or ultrasound imaging but rather a supplemental tool for detecting and staging breast cancer and other breast abnormalities.

MR imaging of the breast is performed for a number of reasons including but not limited to the following:

Assess multiple tumor locations, especially prior to breast conservation surgery.
Identify early breast cancer not detected through other means, especially in women with dense breast tissue and those at high risk for the disease.
Evaluate abnormalities detected by mammography or ultrasound.
Distinguish between scar tissue and recurrent tumors.
Determine whether cancer detected by mammography, ultrasound, or after surgical biopsy has spread further in the breast or into the chest wall.
Assess the effect of chemotherapy.
Provide additional information on a diseased breast to make treatment decisions as well as determine the integrity of breast implants.

Without contrast material, an MRI of the breast can show breast tissue density, cysts, enlarged ducts, hematomas, presence of enlarged lymph nodes and leaking or ruptured breast implants.

By comparing breast images taken before and after contrast material injection, an MRI exam can determine if there are breast abnormalities, whether an abnormality looks benign (non-cancerous) or malignant (cancerous) we well as the size and location of any abnormality that looks malignant.

Breast Ultrasound

The primary use of breast ultrasound today is to help diagnose breast abnormalities detected by a physician during a physical exam (such as a lump or bloody or spontaneous clear nipple discharge) and to characterize potential abnormalities seen on mammography.

Ultrasound imaging can help to determine if an abnormality is solid (which may be a non-cancerous lump of tissue or a cancerous tumor) or fluid-filled (such as a benign cyst) or both cystic and solid. Ultrasound can also help show additional features of the abnormal area.

Doppler ultrasound is used to assess blood supply in breast lesions.

Breast Ultrasound can also be used as a supplemental breast cancer screening, while mammography is the only screening tool for breast cancer that is known to reduce deaths due to breast cancer through early detection. Even so, mammograms do not detect all breast cancers. Some breast lesions and abnormalities are not visible or are difficult to interpret on mammograms. In breasts that are dense, meaning there is a lot of glandular tissue and less fat, many cancers can be hard to see on mammography.

Many studies have shown that ultrasound and magnetic resonance imaging (MRI) can help supplement mammography by detecting small breast cancers that may not be visible with traditional or even digital mammography. MRI is more sensitive than ultrasound in depicting breast cancer, but not all women can tolerate a contrast-enhanced breast MRI. Screening ultrasound can be an alternative to MRI for women who cannot tolerate MRI. If screening MRI is performed, then screening ultrasound is not needed, though ultrasound may be used to characterize and biopsy abnormalities seen on MRI. When ultrasound is used for screening, many abnormalities are seen which may require biopsy but are not cancer (false positives), and this limits its cost effectiveness.

Ultrasound can be offered as a screening tool for women who:

Are at high risk for breast cancer and unable to tolerate an MRI examination.
Are at intermediate risk for breast cancer based on family history, personal history of breast cancer, or prior biopsy showing an abnormal result.
Have dense breasts.
Have silicone breast implants and very little tissue can be included on the mammogram.
Are pregnant or should not to be exposed to x-rays (which is necessary for a mammogram).

Ultrasound Guided Breast Biopsy

Lumps or abnormalities in the breast are often detected by physical examination, mammography, or other imaging studies. However, it is not always possible to tell from these imaging tests whether a growth is benign or cancerous.

A breast biopsy is performed to remove cells—either surgically or through a less invasive procedure involving a hollow needle—from a suspicious area in the breast and examine them under a microscope to determine a diagnosis.

Image-guided needle biopsy is not designed to remove the entire lesion, but most of a very small lesion may be removed in the process of biopsy. Ultrasound or Image-guided biopsy is performed when the abnormal area in the breast is too small to palpitate (or located by hand).

In ultrasound-guided breast biopsy, ultrasound imaging is used to help guide the radiologist's instruments to the site of the abnormal growth.

An ultrasound-guided breast biopsy can be performed when a breast ultrasound shows an abnormality such as:

a suspicious solid mass
a distortion in the structure of the breast tissue
an area of abnormal tissue change

There are times when your doctor may decide that ultrasound guidance for biopsy is appropriate even for a mass that can be felt.

Ultrasound guidance is used in four biopsy procedures:

fine needle aspiration (FNA), which uses a very small needle to extract fluid or cells from the abnormal area.
core needle (CN) which uses a large hollow needle to remove one sample of breast tissue per insertion.
vacuum-assisted device (VAD) which uses a vacuum powered instrument to collect multiple tissue samples during one needle insertion.
wire localization, in which a guide wire is placed into the suspicious area to help the surgeon locate the lesion for surgical biopsy.

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