A bilateral mammogram with tomosynthesis is an advanced medical imaging procedure used for breast cancer screening or diagnosis. This comprehensive exam utilizes three-dimensional technology to evaluate the tissue in both breasts. This method offers a more detailed view than traditional imaging, allowing radiologists to identify potential abnormalities with greater clarity, which can lead to earlier detection and a reduction in follow-up appointments.
Understanding the Components of the Exam
The term “bilateral” simply signifies that the procedure is performed on both the left and right breasts, which is standard practice for routine breast screening and diagnosis. Tomosynthesis, often referred to as digital breast tomosynthesis (DBT) or 3D mammography, represents the technological advancement in the exam. A traditional 2D mammogram captures a single, flat image of the breast tissue from two angles.
Tomosynthesis uses a moving X-ray tube that arcs over the compressed breast, capturing multiple low-dose images from various angles. A computer processes these images to reconstruct a three-dimensional volume of the breast. This allows the radiologist to view the tissue in thin, one-millimeter slices, much like flipping through the pages of a book. This layered approach is designed to overcome the primary limitation of 2D imaging, which is the visual overlap of tissues, providing increased detail.
The Examination Process Step-by-Step
The physical experience of a bilateral mammogram with tomosynthesis is similar to a traditional 2D mammogram. The patient stands in front of the unit while a specially trained technologist positions one breast at a time on the machine’s platform. The process begins with the technologist applying compression by lowering a second plate onto the breast tissue.
Compression is necessary to spread the tissue, reduce motion blurring, and ensure a high-quality image with the lowest possible radiation dose. Although compression may cause temporary discomfort, it is brief, lasting only for the few seconds required to take the X-ray images. During the tomosynthesis portion, the X-ray tube moves in a gentle arc above the breast, capturing a series of projection images.
The technologist instructs the patient to hold still and sometimes hold their breath while the machine scans. Once the images for one view are complete, the plates are released, and the breast is repositioned for a second view (typically top-to-bottom and side angle). This process is repeated for the second breast to complete the bilateral examination. The total time spent under compression for both breasts is comparable to a 2D mammogram, and the entire appointment often takes less than 30 minutes.
Key Advantages of Using Tomosynthesis
The primary clinical advantage of tomosynthesis lies in its superior ability to visualize breast tissue by separating overlapping structures. This is beneficial for women with dense breast tissue, where dense glandular and fibrous tissue appears white on a mammogram, the same color as potential tumors. The slice-by-slice viewing helps the radiologist distinguish between normal dense tissue and an abnormality that might otherwise be hidden in a 2D image.
Tomosynthesis leads to higher cancer detection rates compared to standard 2D mammography, improving the chances of finding cancer at an earlier, more treatable stage. This enhanced accuracy also significantly reduces the rate of false positives. A lower false-positive rate means fewer women are called back for additional imaging or biopsies, reducing patient anxiety and the overall cost to the healthcare system. The reduction in these “recall rates” is a measurable benefit of incorporating tomosynthesis into routine screening.
Preparation and Receiving Results
Proper preparation involves a few steps to ensure the clearest images are captured. Patients should wear a comfortable two-piece outfit, as they will need to remove clothing from the waist up and wear a provided gown. It is necessary to avoid using deodorant, antiperspirant, powders, or lotions on the chest and underarm area on the day of the exam.
These substances can contain particles that may appear on the X-ray images as white spots, potentially mimicking abnormalities. Scheduling the mammogram about one week after the start of a menstrual period can help minimize discomfort for those with breast tenderness. Results are typically interpreted by a radiologist and sent to the ordering physician within a few days. If an area is suspicious or unclear, a follow-up diagnostic mammogram or ultrasound may be recommended.