When you look at mammography or ultrasound images, you might wonder how radiologists make any sense of them. How can they identify potential cancers in those Rorschach tests of gray and white? While even the most advanced imaging technology doesn’t allow radiologists to identify cancer with certainty, it does give them some strong clues about what deserves a closer look. Today we’ll discuss a few things that radiologists are on the lookout for when examining mammography and breast ultrasound images.
Reading a Mammogram
When radiologists look at a mammogram, they’re looking for three primary things:
- Changes from what is seen in previous images
If you’ve had a mammogram before, it is helpful to give your current radiologist access to your previous mammography images. Anytime you visit a new mammography clinic, let them know where you’ve had breast imaging done in the past so they are able to note any changes over time.
Calcifications, which show up as white spots on a mammogram, are divided into two main categories: microcalcifications and macrocalcifications. Macrocalcifications are typically the result of benign processes and do not require biopsy. Microcalcifications also are often associated with benign conditions, but their appearance in clusters or lines may indicate the presence of cancer. Clustered microcalcifications are associated with both DCIS, known as “stage 0” or non-invasive breast cancer, as well as invasive breast cancer. Bear in mind, however, that calcifications are very common, appearing in half of mammograms of women over 50.
Masses comprise a variety conditions, including cysts, benign solid tumors, and malignancies. Their size, shape, borders, and internal composition can give insight into whether they represent cancer. Cancerous tumors often appear as white masses with blurry or spiked borders, which indicate infiltration into the surrounding tissue. Cysts are often indistinguishable from solid tumors on a mammogram, so ultrasound is often used to determine whether a mass is solid or fluid filled (a cyst).
Ultrasound Follow Up
Breast ultrasound is among the most common modalities used in mammography follow up. It is particularly valuable for distinguishing solid from fluid masses, as fluid appears as the darkest material on a sonogram, and solid lesions may appear a little brighter or a little darker than their surroundings. Malignant masses typically appear on ultrasound as nodular structures that are slightly darker than their surroundings and have ill-defined borders. If an ultrasound shows only a completely fluid-filled mass, this is identified as a simple cyst that does not require follow up. However, if the area is solid or contains some solid material (which would appear brighter within the dark area), a biopsy may be ordered to investigate further.
If you are called back after a screening mammogram, try not to worry. While more than 10% of women may be called back for additional testing after a screening mammogram, fewer than 10% of those called back are found to have cancer. A biopsy is the only way to positively identify cancer. Iowa Radiology prides itself on exceptional patient care, which includes providing the information you need to understand procedures and what they may indicate. For more information about mammography, download our free ebook.
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 "Findings on a Mammogram." Susan G Komen, 8 Aug 2017. Accessed 22 May 2018.
 "Screening mammography for women 40-49 detects more cancers compared with older age groups." Medical Xpress, 13 March 2018. Accessed 22 May 2018.