OBJECTIVES
Routine identification of the nipple, lesions and pathology with a skin marker in both screen-film and digital mammography on all patients eliminates uncertainty and the necessity for any repeat examinations. Many mammography facilities use these small self-adhesive skin markers to readily identify the nipples, possible abnormal lesions and pathology of all types. Even with the advent of digital mammography nipple markers continue to be beneficial. The markers allow immediate identification of the nipple without adjusting the window and level settings. These markers are placed on the patient before her mammogram and subsequently serve as a reliable and stable landmark on mammograms for the registration of multiple images.
Triangulating a Lesion Viewed in One View Only:
Very often in Mammography there is a suspicious area of concern that can only be appreciated in one view. There are two recognized methods that identify a plane of possibility where the lesion could be located. These methods help to define an area where the lesion is probably located thereby reducing read time.
The two methods typically used today are; the Arc method and the Right angle or Cartesian methods. Both of these methods benefit from the placement of a nipple marker prior to the exam. The Cartesian method has proved to be more accurate for lesions on the periphery of the breast while both methods are helpful for central lesions.
- Cartesian Method (right angle) (preferred method)
Guidelines:
To locate lesion in 2nd view draw a line through the nipple and perpendicular to chest wall in each view. Locate depth along that line.
This right angle technique works well for central lesions and is a more reliable technique for localizing peripheral lesions seen on only one view. First, the nipple marker is used to help establish a perpendicular nipple pectoral line on both the CC and the MLO views. Then measure from the nipple marker to the area of concern and transfer this measurement to the projection where the lesion is not immediately appreciated (See Diagram1&2 below).
CC= 1cm 2cm 3cm along PNL
MLO= 1cm 2cm 3cm along PNL to chest wall
The value of this technique can be seen in Image A and B where the lesions noted in the CC view at 40mm, 70mm and 95mm are all found at the same distance in the MLO view. This holds true even for the two more peripheral findings.
- Arc Method
Guidelines:
To locate lesion in 2nd view swing an arc through the lesion from the nipple .Repeat in second view
To utilize this method locate the nipple, or preferably the nipple marker, and measure the distance to the area of concern in the projection where the lesion is noted. In the projection where the lesion is not evident an arc is established at the distance measured in the first projection (Diagram 3 and 4).
This method will work well for central lesions but is not accurate for peripheral lesions of the breast. Image C and D demonstrate this well, as the lesion noted in the retroareolar area in the MLO view at 7mm is found in the CC view at 40mm.
C. L-CC D. LMLO
In conclusion, the Right angle technique is the more consistent and most precise method. The Arc technique is fairly accurate for central lesions, but can be a pitfall for lesions at the periphery of the breast in the subareolar area, or in the axilla. These quick techniques are generally helpful for a basic approximation.
Using Nipple-To-Lesion Distance Only To Find a Missing Lesion:
Placement of nipple markers can allow accurate measurement of lesions and their distance from the nipple. Findings on mammographic images are generally reported with the o’clock position and distance from the nipple. If a potential lesion can only be identified in one view additional workup is required and every effort needs to be made to determine its location in another projection.
Using the nipple-to-lesion distance can aid in lesion identification. By determining how far back from the nipple the lesion is on one view the approximate location of the lesion can then be ascertained on the other projection. If two views are not sufficient for lesion identification, triangulation of the lesion with additional imaging is then warranted.
Case study
Case Study 1: A 72 year-old female presented for a screening mammogram. Within the superior aspect of the left breast 15cm posterior to the nipple on the MLO view is a 5mm ill-defined mass. To determine a more precise location for the mass the craniocaudal (CC) view is reviewed. In this example the medial aspect of the breast 15cm posterior to the nipple is clean with no masses. Therefore, based on location and its distance from the nipple using the MLO view this lesion is likely in the far posterior and lateral aspect of the breast on the CC view at approximately one to two o’clock where there is the suggestion of a mass. Additional imaging including a standard 90 degree lateral view and spot compression views were performed along with an ultrasound and ultrasound guided biopsy (not shown). The biopsy findings were compatible with infiltrating lobular carcinoma.
Benefits of Routine Nipple Marking in Mammography:
The placement of nipple markers not only provides a high quality examination for the patient, they also aid the radiologist in reading the mammogram by eliminating confusion and saving time. This is true even when dealing with a FFDM system. The time here is saved with less windowing, less leveling and less magnification.
Accurate identification of nipple location on mammograms can be challenging because of variations in image quality and in the nipple projections. This can result in some nipples being nearly invisible on the image. The small radiopaque marker placed on each nipple allows the nipple to be viewed as a reference point on the film for concise nipple-to-lesion distance, helpful in cases with subareolar masses, and in the post-surgical breast with architectural distortion.
Disposable nipple markers make routine nipple marking in mammography possible because they are readily accepted by the patient, easy to use, and cause no significant patient delay.
Using nipple markers helps to eliminate the cost of repeat examinations. In addition to the actual cost for the repeat examination there is the hidden cost of time lost at work for those outpatients who had to return for additional radiographs. Of even greater importance to the patient is the anxiety generated by the report needed for additional imaging which can be eliminated with routine nipple marking.
Case Studies
Subareolar Masses
Nipple markers are particularly helpful in cases with subareolar masses. Depth divides the breast arbitrarily into anterior, middle and posterior thirds, and immediately behind the nipple is the subareolar region.
When a nipple marker is not used it can be difficult to distinguish the nipple from a well-circumscribed mass in the subareolar region. Additional imaging would be required which may invoke unnecessary anxiety for the patient.
Case 1
Case Study 1: A 39 year-old female presents with a history of a tender palpable right breast mass. The mass underwent ultrasound guided core needle biopsy with results compatible with a fibroadenoma. Previously behind the right nipple is one bi-lobed mass versus two separate nodules. (A biopsy clip is noted to be positioned 1.5cm medial to the most medial portion of the lesion.) The fibroadenoma in this case is just beneath the skin surface. The nipple marker is extremely useful to eliminate any uncertainty in identifying the mass from the nipple.
Case 2
Case Study 2: An asymptomatic 72 year-old female presents with a stable 1cm well-circumscribed mass directly behind the left nipple since 2002. The mass is slightly superior on the MLO view. The nipple marker is extremely useful to quickly identify the mass from the nipple.
Suboptimal Exposure
Variations in image quality can make accurate identification of the skin line and of the nipple difficult. The absence of the nipple as a stable landmark in these circumstances generates additional read time for the radiologist. The generally simple registration of medial from lateral on the CC view and superior from inferior on the MLO view is challenged when the nipple and skin line are not visualized. Even with the advent of digital mammography nipple markers continue to be beneficial. The markers allow immediate identification of the nipple without adjusting the window and level settings.
Case 3
Case Study 3: A 74 year-old female presented for a screening mammogram. The skin surface cannot be seen and the use of a nipple marker allows the nipple to be identified.
Post-Surgical-architectural Distortion
In patients with a history of lumpectomy or reconstructive breast surgery there can be significant post-surgical architectural distortion which not only affects the appearance of the breast parenchyma but can also alter the position of the nipple. Without placement of nipple markers during initial and subsequent post-surgical imaging, the nipple may be mistaken for a mass requiring additional imaging.
In these cases, translucent scar markers are also valuable to visualize the scar bed as the surgical trauma heals. The scar bed can easily be mistaken for a new lesion and more critically a new lesion can be dismissed as the scar bed.
Case 4
Case Study 4: A 42 year-old female presents with a history of left lumpectomy for malignancy. She has additional history of reduction surgery performed many years prior to lumpectomy surgery. The nipple in these images is markedly displaced by post-surgical changes identified with a nipple marker.
Case 5
Case Study 5: A 70 year-old female presents with a history of right lumpectomy for malignancy followed by radiation therapy. There is post-surgical deformity in the upper aspect of the breast leading to marked displacement of the nipple identified with a nipple marker.
SUMMARY:
The old saying goes…”the more things change, the more they stay the same”. This is so true for breast imaging. Our specialty is specific, intense and detailed. To identify tiny distortions in wildly varying complicated breast tissue all landmarks are useful. We, as the technologist, are charged with demonstrating all the breast tissue clearly and precisely. Marking the landmarks, lesions and scars help us to recognize what projections are needed to show any and all missing tissue. These inexpensive innocuous little markers help the radiologist to make quick, expert, accurate decisions regarding breast abnormalities.
The breast imaging team’s job is to save lives, make treatment shorter, easier and more affective. Any aids that assist us in that mission are more than welcome.
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