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 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.
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.
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.
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).