Screening Tests After a Mammogram

Mammograms are the first step in screening for all women. However, in women with dense breasts, there are cancers that will not show on a mammogram. Additional tests after a mammogram may find these cancers. Importantly, women should not skip their mammogram, as some cancers are only seen on a mammogram, even in dense breasts.

When making a choice about an additional screening test after a mammogram, there are things to consider. For instance, additional screening tests may find things that need even further testing that turn out not to be cancer (known as a false positive). Discuss with your health professional what might be right for you.

The tests listed below are not affected by breast density and can find cancers that will not show on a mammogram (either 2D or 3D).

Ultrasound (US)
Molecular Breast Imaging (MBI)
Contrast-Enhanced Mammogram (CEM)
Magnetic Resonance Imaging (MRI)

Ultrasound (US)

Ultrasound is the most widely available additional test used after a mammogram. Ultrasound uses sound waves to create images of your breasts. It does not involve radiation or an injection. Gentle pressure is applied to the breasts with a wand (known as a transducer), a plate-like frame, or by lying face down on a table and lowering each breast into an opening. Ultrasound rarely causes discomfort and screening takes about 15 to 20 minutes.

Ultrasound is most often performed on a small area of the breast (known as a “limited” ultrasound).
A “limited” ultrasound is performed due to symptoms (like a lump), or other finding on a mammogram.
A “screening” ultrasound (when no symptoms are present) of the whole breast(s) is sometimes performed in women with dense breasts.
Screening ultrasound can be used when MRI is recommended but cannot be performed.

Molecular Breast Imaging (MBI)

Molecular breast imaging involves injection of a radioactive material into your vein. About 5 minutes after the injection, your breast is placed between two detectors similar to a mammogram but with less pressure. An MBI test takes at least 40 minutes. MBI is not yet widely available.

MBI results in radiation exposure to the full body (totaling about 4 times the amount of radiation as from a mammogram, but still considered small and within acceptable limits).
MBI can be used to look at areas of concern seen on a mammogram or breast ultrasound.
For women with dense breasts, some breast centers also use MBI for additional screening (when no symptoms are present) after a mammogram.
Where available, MBI is an option when MRI cannot be performed.

Contrast-Enhanced Mammogram (CEM)

Contrast-enhanced mammogram (CEM) is a specialized mammogram that uses injection of an iodine dye into a vein. About 2 minutes after the injection, you will have a mammogram and two sets of images will be taken of each breast. One set is like a standard 2D mammogram, and the second set (with the dye) helps show cancers. CEM uses about twice as much radiation as a standard mammogram (but still low and safe amounts) and takes about 10 minutes. CEM is a newer technology that is becoming more widely available.

The iodine dye is the same dye used in CT scans (be sure your health team knows if you have had a bad reaction to CT scan dye).
CEM is being studied for breast cancer screening (when no symptoms are present), especially in women with dense breasts.
CEM finds cancers at a rate similar to that of an MRI.
Where available, CEM is an option when MRI cannot be performed.

Magnetic Resonance Imaging (MRI)

Contrast-enhanced Magnetic Resonance Imaging involves injection of a non-radioactive solution (gadolinium contrast) into your vein. The exam is done in the tunnel of a large magnet. You lie on your stomach and your breasts fit into two openings. The machine makes loud noises while generating images. MRI takes about 25 minutes (or 10 minutes for an “abbreviated” MRI, though abbreviated MRI is not offered at all imaging centers).

MRI finds more cancers than any other screening test.
For women at high risk for breast cancer aged 25-29, yearly MRI screening alone is recommended. If at high risk after age 30, both mammography and MRI are recommended every year. (For European guidelines by country, see DenseBreast-info/Europe).
For women who have dense breasts and no other risk factors who seek additional screening, MRI should be considered starting at age 40 (if available).
Women who are claustrophobic may want to discuss with their health professional whether it might help to take a sedative (a medication to reduce anxiety) before the examination.

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