Mammograms and Beyond: Breast Cancer Imaging, Explained

June 12, 2026

Back view of a woman undergoing digital breast tomosynthesis on modern diagnostic equipment

If you’ve ever wondered why your doctor ordered one type of breast imaging over another, or why a routine mammogram led to another mammogram, an ultrasound or MRI, you’re not alone. Breast cancer screening can involve several different imaging tools, each designed to do something different.

Holly Marshall, MD, a radiologist at University Hospitals, explains what each type of imaging does and what to expect if your annual mammogram requires more screening.

The Gold Standard: The Mammogram

Mammograms use low-dose X-rays to create images of breast tissue, and they’re the most widely recommended tool for detecting breast cancer. Annual screening mammograms beginning at age 40 are recommended for most women without a family history or other risk factors.

Mammograms are performed using 3-D technology, called tomosynthesis, which takes images from multiple angles to build a layered, three-dimensional picture of the breast rather than a single flat image. This gives radiologists a clearer view, improving cancer detection rates and reducing the need for additional imaging.

Many women wonder how much radiation they’re exposed to from their routine mammogram. “Today’s mammograms use a very low dose, equivalent to about eight weeks of normal background radiation that you get just from daily life or taking a cross-country airplane flight,” says Dr. Marshall. “Any risks are absolutely outweighed by the opportunity to detect breast cancer early.”

Another common question is how often to get a mammogram, with some guidelines suggesting every other year may be enough for some women. “We continue to recommend annual screening for every woman,” says Dr. Marshall.

What Is Dense Breast Tissue, and Why Does It Matter?

Your mammogram results will include a note about your breast density. This is important information – and for about 40-50% of women, it may prompt a conversation about additional screening.

Breast tissue is classified on a scale from fatty to extremely dense, based on how much fibroglandular tissue is present. Dense breast tissue presents two challenges: it increases the risk of developing breast cancer, and it makes cancer harder to see on a mammogram. “On imaging, dense breast tissue is white, and any cancer is also white,” Dr. Marshall explains.

If your mammogram report shows dense breast tissue, it’s important to have a conversation with your healthcare provider about additional screening.

Breast density can change over time, as a result of hormonal changes like perimenopause or significant weight fluctuation. “We’ve seen a lot of patients go from fatty or scattered densities to dense breast tissue with weight loss,” Dr. Marshall notes, adding that GLP-1 medications have made this shift more common.

Ultrasound, MRI and Contrast-Enhanced Mammography (CEM)

For patients who may benefit from more than a screening mammogram, whether due to dense breast tissue or an elevated risk of developing breast cancer, there are several common types of imaging.

Ultrasound uses sound waves to visualize breast tissue in more detail, including whether a suspicious area is a solid mass or a fluid-filled cyst.
Contrast-enhanced mammography (CEM) is a newer option that combines mammography with contrast dye to show blood flow. Unusual blood flow patterns can be a sign of breast cancer.
Breast MRI, the most sensitive supplemental screening tool, uses a magnetic field, radio waves and a contrast dye to find abnormalities. MRI is typically recommended for women with a higher risk of breast cancer, those with a BRCA1 or BRCA2 gene mutation, women with a strong family history of breast or ovarian cancer, and women who received chest radiation therapy before age 30. While MRI is helpful in identifying breast cancer, it can also detect abnormalities that aren’t cancer, requiring additional follow-up or biopsies.

“It’s also important to note that a supplemental screening exam does not replace a mammogram,” adds Dr. Marshall.

What Happens When Something Needs a Closer Look

If your screening mammogram detects something that needs a closer look, you’ll be contacted to come back for additional imaging.

Follow-up imaging can include additional mammogram images or an ultrasound to better visualize a specific area. If an MRI or contrast-enhanced mammography was already performed, follow-up may involve targeted ultrasound or additional mammogram imaging to confirm what was seen.

If a biopsy is needed to rule out cancer, that will be discussed with you. Two common procedures are stereotactic biopsy, which uses mammogram imaging to guide a needle precisely to the area of concern, and ultrasound-guided biopsy, which uses real-time ultrasound to guide the needle.

A finding on any of these studies does not necessarily mean cancer. The goal of the follow-up is to get a clear answer as quickly as possible.

Know Your Risk – and Talk to Your Doctor

The right type of imaging is typically determined by a number many women don’t know they have: their lifetime breast cancer risk. There are several risk assessment tools. One is the Tyrer-Cuzick Risk Model, which gained widespread attention when actress Olivia Munn shared that the tool led to her breast cancer diagnosis. Dr. Marshall recommends that women have a formal risk assessment performed as early as age 25.

If the tool shows your lifetime risk is 20 percent or greater, earlier or additional screening with MRI, contrast-enhanced mammography or ultrasound, may be advised.

A few other questions worth raising include:

What is my breast density? If your tissue is dense, ask whether supplemental screening is appropriate for you.
Should I be screened earlier or more frequently? For women at high risk, earlier and more intensive screening may be recommended, starting before age 40.
Is annual mammography right for me? The answer is almost always yes, starting at 40.

The good news is breast cancer is highly treatable when it’s caught early, and the imaging tools available today make that more possible than ever. The most important step is put that next mammogram appointment on your calendar.