A mammogram is a specialized X-ray imaging technique designed to examine breast tissue. This procedure plays a fundamental role in the early detection of breast cancer, often identifying changes years before a lump can be felt. Early detection significantly improves treatment outcomes and survival rates. The purpose of the exam determines its classification: screening or diagnostic.
Defining Screening and Diagnostic Mammograms
The classification of a mammogram as screening or diagnostic depends on the patient’s health status and the reason for the examination. A screening mammogram is performed on asymptomatic patients, meaning they have no symptoms like a lump, pain, or nipple discharge. This annual preventative measure typically consists of two standard X-ray views of each breast, designed to look for subtle signs of cancer.
A diagnostic mammogram, in contrast, is an investigative tool used when a specific concern exists. It is ordered for patients experiencing symptoms or those who had an abnormal finding on a recent screening mammogram. Because the goal is to investigate a particular area, the radiologist often takes additional, focused images, which may include special magnification or spot compression views.
The diagnostic classification means the test is used to confirm or rule out a disease process, moving beyond simple detection. During the procedure, the radiologist is typically present to review the images in real-time, which allows for immediate decision-making on whether more views or an ultrasound are necessary before the patient leaves the clinic. This immediate assessment contrasts with a screening mammogram, where results are often sent days later.
Understanding the Mammography Procedure
The physical experience of undergoing a mammogram is similar regardless of its classification. Patients are instructed not to apply deodorant, antiperspirant, powders, lotions, or creams to their chest or underarm area on the day of the exam. These products can contain metallic particles that may appear as white spots on the X-ray image, potentially mimicking fine calcifications.
During the procedure, the breast is positioned on an imaging plate and compressed with a clear plastic paddle. Compression is necessary for several reasons. It spreads the breast tissue to reduce overlap that might obscure a lesion and holds the breast still to prevent motion blur. Compression also allows the use of a lower X-ray dose by reducing the tissue thickness.
Modern mammography often utilizes three-dimensional (3D) technology, known as digital breast tomosynthesis (DBT). Unlike traditional two-dimensional (2D) imaging, DBT involves the X-ray tube moving in an arc, taking multiple low-dose images from various angles. A computer reconstructs these “slices” into a 3D volume, allowing the radiologist to look through the tissue layer by layer. This layered view is beneficial for patients with dense breast tissue, helping distinguish between overlapping normal tissue and potential abnormalities.
Follow-Up Steps After an Abnormal Screening Result
When a screening mammogram yields an abnormal finding, the process transitions immediately to diagnosis, beginning with a recall for additional imaging. This initial abnormality is often categorized as BI-RADS 0, meaning the finding is incomplete and requires further evaluation. Common findings requiring follow-up include masses, suspicious calcifications, or architectural distortion (structural disarray of the tissue).
The first step in follow-up is almost always a diagnostic mammogram, focusing specifically on the area of concern with magnified or spot compression views. Alongside this, a breast ultrasound is frequently performed, which uses sound waves to determine the nature of a mass. The ultrasound can quickly determine if a mass is a simple fluid-filled cyst (nearly always benign) or a solid mass requiring further investigation.
If the diagnostic imaging still shows a suspicious solid mass or cluster of calcifications, the definitive diagnostic test is a biopsy. A core-needle biopsy is the standard procedure, involving the radiologist using imaging guidance (often ultrasound or a specialized mammography technique) to insert a hollow needle and remove a small tissue sample. This tissue is sent to a pathologist for microscopic examination to confirm whether cancerous cells are present. Only a small percentage of women recalled for follow-up testing ultimately receive a cancer diagnosis; the majority of abnormal findings are found to be benign.