A mammogram is a specialized X-ray used for breast cancer screening, but breast implants introduce complexity to the procedure. Both saline and silicone implants contain materials opaque to X-rays, making it difficult to visualize the underlying breast tissue clearly. This challenge necessitates specialized techniques and modifications to the standard screening process to ensure maximum breast tissue examination. Understanding these procedural differences is important, as they impact both the safety and diagnostic effectiveness of the examination.
Modifications to the Standard Procedure
The primary adaptation for mammography in patients with breast implants involves a technique known as the Eklund Displacement Views, or Implant Displacement (ID) views. This method is specifically designed to isolate the natural breast tissue from the opaque implant. The goal is to maximize the tissue available for compression and imaging without damaging the prosthesis.
During the procedure, the technologist gently pushes the implant backward toward the chest wall. Simultaneously, they pull the natural breast tissue forward and onto the mammography plate for compression. This careful maneuvering allows the X-ray beam to capture a clearer image of the breast parenchyma, where cancer most often develops.
A standard screening mammogram typically requires four images, two views for each breast. For a patient with implants, the Eklund technique requires four additional displacement views, resulting in a total of eight images. This extended process helps to improve the visibility of the glandular tissue but also means the examination takes longer than a routine mammogram.
Safety Concerns and Minimizing Rupture Risk
A frequent concern among patients is the possibility of the compression causing the implant to rupture. While the risk of a mammogram causing a rupture is very low, the procedure must be performed by a technologist experienced in the implant displacement technique. Modern implants are engineered to withstand significant pressure, and the compression applied during the displacement views is carefully controlled.
For patients who have pre-existing issues, such as a hardened scar capsule around the implant (capsular contracture), the maneuver can be more uncomfortable. However, the use of the displacement views means that the implant itself is not subjected to the full compression force used on the breast tissue. The technologist uses only the minimum compression required to obtain a diagnostic image.
Patients must inform the facility and the technologist about their implants before the exam begins. This allows the staff to allocate the necessary time and ensure the procedure is performed using the specialized Eklund views. If an implant is already weakened or leaking, the mammogram may reveal the issue rather than cause it.
Diagnostic Challenges and Limitations
Despite the use of specialized displacement views, the presence of breast implants still presents diagnostic limitations. Implants appear as dense, white objects on the X-ray image, which makes it impossible to visualize any breast tissue directly behind them. This obscuring effect can potentially hide small tumors that are located near the chest wall.
The amount of obscured tissue can vary significantly, ranging from approximately 9% to 44% of the glandular tissue, depending on the implant’s size and placement. Implants placed underneath the chest muscle (subpectoral) often obscure less tissue than those placed over the muscle (subglandular), making screening slightly more effective in the former case. Even with the Eklund views, the area immediately beneath the implant capsule remains difficult to image accurately.
This limitation means that a mammogram may have a reduced sensitivity for cancer detection in patients with implants compared to those without. Studies have shown that the cancer detection rate may be lower in this population, which is why additional imaging tools are often considered.
Role of Supplemental Imaging
Given the diagnostic limitations of mammography in patients with implants, supplemental imaging techniques play an important role in comprehensive screening and diagnosis. These tools are used in addition to, not as a replacement for, the modified mammogram. They help to evaluate the areas of the breast that the X-ray cannot penetrate and can also assess the integrity of the implant itself.
Breast ultrasound is a common follow-up tool that uses sound waves instead of radiation and is very effective at imaging tissue near the chest wall. It is frequently used to investigate specific areas of concern that may be obscured by the implant or to characterize a palpable lump. Ultrasound is also valuable for evaluating the condition of the implant, as it can detect signs of rupture, such as fluid outside the shell.
Magnetic Resonance Imaging (MRI) is considered the most sensitive tool for screening high-risk patients with implants. MRI provides detailed images of both the breast tissue and the implant capsule without requiring compression. It is particularly accurate for detecting silicone implant rupture, which appears as a characteristic “linguine sign” on the scan, though it is more expensive and time-consuming.