Breast cancer detection relies on imaging techniques, and early identification improves treatment outcomes. Three-dimensional (3D) mammography, also known as breast tomosynthesis, is an advanced imaging method enhancing the visibility of breast tissues. This technology offers a more detailed view compared to traditional methods, aiding in the detection of subtle changes indicating cancer.
How 3D Mammography Works
Three-dimensional mammography captures multiple images of the breast from various angles. During the procedure, the X-ray arm moves in a small arc over the compressed breast, acquiring low-dose images. These individual images are then digitally reconstructed by a computer to create a layered, three-dimensional view of the breast tissue. This process effectively produces thin, millimeter-sized “slices” of the breast, allowing radiologists to examine the tissue layer by layer.
This multi-angle approach differs from traditional 2D mammography, which captures only two flat images of each breast. By creating these detailed cross-sections, 3D mammography minimizes tissue overlap, obscuring abnormalities in 2D images. The ability to “slice” through breast tissue allows for clearer visualization, making abnormalities more apparent, particularly in dense breast tissue.
Identifying Cancerous Features
On a 3D mammogram, radiologists look for specific visual characteristics indicating breast cancer. One common feature is masses, which are three-dimensional lesions within the breast tissue. Suspicious masses often appear with irregular shapes, spiculated (spiky) margins, and a high density, meaning they look lighter or whiter on the image compared to surrounding fatty tissue.
Another characteristic is calcifications, tiny calcium deposits that show as small, bright white spots. While many calcifications are benign, suspicious calcifications tend to be small, numerous, clustered, and may have a pleomorphic (varied) or linear pattern. In contrast, benign calcifications are typically larger, more scattered, and rounder.
Architectural distortion is a subtle but significant finding where the normal pattern of breast tissue is disrupted without a clear mass visible. This appears as fine lines or spicules radiating from a central point, or a focal retraction or straightening of the tissue. 3D mammography improves the detection of architectural distortion, which can be an early sign of breast cancer.
Differentiating Findings
Radiologists use 3D mammography’s enhanced detail to distinguish suspicious findings from normal breast tissue or benign conditions. The ability to view the breast in thin slices allows for a more precise assessment of the margins and internal characteristics of any abnormality. For instance, benign conditions like cysts or fibroadenomas typically have smooth, well-defined, and circumscribed borders.
The layered images help radiologists determine if an apparent abnormality is superimposed normal tissue from different planes, which can mimic a mass on a 2D image. By scrolling through the slices, they confirm if a finding is a distinct lesion or an artifact of tissue overlap. This detailed visualization reduces false positives, preventing unnecessary investigations.
What Happens After a Suspicious Finding
If a suspicious area is identified on a 3D mammogram, it does not automatically mean cancer. Often, additional imaging is recommended for further evaluation. This may include a diagnostic mammogram with more detailed views, or other imaging, such as a breast ultrasound or magnetic resonance imaging (MRI).
If the suspicious finding persists after these tests, a biopsy is typically the next step. A biopsy involves removing a small sample of breast tissue for microscopic examination by a pathologist, providing a definitive diagnosis. Most callbacks for suspicious findings, even those requiring a biopsy, ultimately turn out to be benign.