15.1 Implant Displaced (ID), Nipple in Profile, and Anterior Compression

15.1 Implant Displaced (ID), Nipple in Profile, and Anterior Compression

Quick Answer: Implant-displaced (Eklund) views pull native tissue forward and hold the implant back against the chest wall so the parenchyma can be fully compressed. They do not replace implant-in-place CC and MLO. Add a nipple-in-profile extra view when the nipple is not profiled on the standard pair, and use anterior (split) compression when thick posterior tissue leaves the anterior breast under-compressed. Do not force a frozen implant, and do not trade away posterior tissue just to put the nipple on the image.

ARRT Mammography Procedures 2.A treats these three additions as positioning solutions, not as optional extras. Each one exists because a standard CC/MLO pair can include anatomy on the detector and still fail to show it well. Exam items usually name a specific failure — implant overlay, a buried nipple, or a thickness mismatch — and ask which view fixes that failure.

Implant-displaced (Eklund) technique

Breast implants occupy volume and stop x-rays. On a routine CC or MLO taken with the implant in the field, a large fraction of fibroglandular tissue is hidden behind the prosthesis or only lightly compressed because the implant reaches the paddle first. The displacement method described by Eklund, labeled ID in standard MQSA/ACR view codes, is the U.S. positioning answer to that problem.

The maneuver

Palpate the implant margins before you set the paddle. Stand the patient for the intended projection (CC or MLO), then:

1. Pull the native breast tissue anteriorly, off the implant, with both hands.
2. Displace the implant posteriorly so it flattens against the chest wall — and, on the CC, behind the detector tray whenever it will go.
3. Bring compression onto tissue only. The paddle edge should land at the tissue–implant interface, not on the dome of the implant.
4. Confirm that as much implant as possible is out of the beam before you expose.

The result is a thinner, better-immobilized slab of parenchyma with contrast and sharpness closer to a non-augmented breast. Subpectoral (retropectoral) implants are often easier to hold back because pectoralis major helps pin the device. Subglandular (retroglandular) implants can still be displaced if they are mobile. Mobility, not pocket, is the deciding factor.

Implant paddle

Use the facility's implant / displacement paddle when it is available. It is a smaller, often more flexible paddle whose chest-wall edge can sit at the implant–tissue interface without trapping the prosthesis under a full-size plate. If the only paddle on the unit is a standard 18×24 or 24×30 cm plate, ID is still performed — the paddle is a helper, not a substitute for the hand maneuver. Do not choose a tiny spot paddle for a screening ID series. Spot paddles are for a region of interest, not for displacing an entire implant.

Implant-in-place views are still required

ID images show anterior and mid-breast tissue. They do not replace the implant-in-place CC and MLO. Implant-in-place views are the images that include posterior tissue wrapping around the implant, the implant contour itself, and (on MLO) much of the axillary tail relative to the device. A complete bilateral implant screening study is therefore typically eight images: RCC, LCC, RMLO, and LMLO with the implant in the field, plus the same four labeled ID. Unilateral augmentation still gets in-place plus ID on the implanted side and the usual two-view pair on the opposite breast.

Compression on implant-in-place views is immobilization, not vigorous tissue compression. You are not trying to flatten the prosthesis. Prior chapters already covered manual technique for these views; it still applies. Automatic exposure control that sees a radiopaque implant will terminate on the implant and underexpose surrounding tissue. Use a manual chart (or a carefully chosen AEC cell placed only over tissue, if protocol allows) for implant-in-place images. Once the implant is successfully displaced, ID views are usually exposed with AEC because the cell can sit under parenchyma.

Saline versus silicone does not cancel ID

Saline is less radiopaque than silicone, and a deflated saline implant is a different clinical problem, but fill material does not change the need for ID when tissue can be displaced. Both occupy volume, both limit compression, and both hide tissue on in-place images. Do not skip ID because it is 'only saline.' Do not skip ID because the implant is subpectoral. If you can pull tissue forward, you displace.

Encapsulated or frozen implants

Capsular contracture can make an implant round, firm, and immobile. The Eklund maneuver then fails or displaces only a sliver of tissue. Do not force it. Forcing a frozen implant risks pain and implant injury, and it still will not produce a diagnostic ID. Document limited or unsuccessful displacement in the technologist notes so the interpreting physician sees why tissue remains hidden. Complete the implant-in-place CC and MLO with reduced compression. Many protocols then add a 90-degree lateral (ML or LM) to show tissue that the oblique leaves behind the capsule; some add an LMO. Those extras are problem-solving. They are not a license to omit the attempt at ID when the implant is actually mobile.

After mastectomy reconstruction there may be little or no native tissue to pull forward. Document that ID is not feasible and obtain the in-place views that the remaining anatomy allows.

Nipple in profile

The nipple is both a landmark and a hiding place. When it is not in profile, retroareolar tissue stacks on itself, the nipple can mimic a mass, and a real subareolar mass can hide in that stack. ACR clinical-image criteria expect the nipple in profile on at least one of the two standard views. The operational ARRT rule is: if the nipple is not profiled on the CC or the MLO, add a dedicated nipple-in-profile extra view rather than repeating a poor standard image.

Do not sacrifice posterior tissue

The classic trap is rolling the breast until the nipple sits on the profile line and, in the process, letting posterior medial or posterolateral tissue fall off the detector. Posterior tissue on the screening CC/MLO is non-negotiable. If putting the nipple in profile would lose chest-wall tissue, keep the posterior tissue on the standard view and take a separate extra view whose only job is the nipple and retroareolar region.

How to take the extra view

Explain why you are adding an image. Reposition the same projection (usually CC, sometimes MLO) so the nipple is tangent to the beam, centered when possible, and shown with at least about 2 cm of retroareolar tissue behind it. You are not repeating the entire breast; you are clearing the subareolar zone. Label with standard laterality and projection codes. This is still a CC or MLO extra view, not a new ACR letter. A nipple marker can help when the nipple is extremely difficult to profile, but a marker is not a substitute for a profiled extra view when the retroareolar tissue itself is the question.

Anterior compression (split compression / anterior paddle)

Large and pendulous breasts are thicker at the chest wall than at the nipple. A full-size paddle that applies adequate force posteriorly often leaves the anterior breast under-compressed: the anterior mound droops (the camel-nose look on MLO), Cooper ligaments are not spread, contrast falls, and motion blur appears near the nipple. That is not a reason to crush the posterior breast harder. It is a reason to split the compressed volume.

Anterior compression — also called split compression or an anterior-paddle view — uses a smaller or anterior paddle to compress only the anterior breast as a second image. The posterior breast has already been documented on the standard CC/MLO. The anterior image now gets a thinner, uniform slab, open ligaments, and a nipple that can be held in profile without fighting axillary thickness.

This is not spot compression. Spot compression is a small region-of-interest paddle over a possible mass or asymmetry. Anterior compression covers the whole anterior breast. It is also not mosaic or tile imaging of a breast that will not fit on one detector; tiling is a field-of-view problem, anterior compression is a thickness-gradient problem. Some very large breasts need both.

Matching the problem to the view

Labeling

MQSA requires laterality and view near the axilla using accreditation-body codes. ID is the modifier for implant displaced (examples: RCCID, RMLOID). Nipple-in-profile and anterior-compression images keep the projection code (CC or MLO) plus the facility's extra-view annotation. Do not invent a new letter. M (magnification) and TAN (tangential) are separate modifiers used with the same laterality-first pattern; they do not replace ID.

Exam traps

• Treating a successful ID series as permission to skip implant-in-place views.
• Skipping ID because the implants are saline or subpectoral.
• Forcing an encapsulated implant instead of documenting and completing in-place imaging.
• Losing posterior tissue on CC/MLO in order to put the nipple in profile.
• Using a spot paddle when the order is anterior compression of the whole anterior breast.