(3) Discerning the implant position on mammography is often achieved on the non-implant displaced MLO view. On this view, both pectoralis major and the implant are seen, thereby most often discerning the location of the implant as related to the muscle.
Centers that routinely perform mammograms often provide these women with routine full field routine CC (cranio-caudal) and MLO (mediolateral oblique) views, as well as additional "implant displaced" CC and MLO views (Figure 2).
Figure 2(a) shows the MLO view of right breast for the selected case, the small inset picture shows zoomed out ROI region that is cropped and provided to the algorithm as input.
Each case contains four different images (CC, MLO views for left and right breast) along with annotation information of detected image region.
In an MLO view, the x-ray beam enters medially and the film is located laterally.
The MLO view is not orthogonal to the CC view but oriented 30[degrees] to 60[degrees] to it.
On an MLO view, the label RMLO or LMLO will be placed near the axilla in the upper breast.
Because of this oblique orientation, a mass that is above the PNL on the MLO view could actually be in the lower half of the breast.
For example, if a nonpalpable, suspicious, hyperdense, irregular, 1.5-cm right breast mass is seen laterally on the CC view, above the PNL on the MLO view, but below the PNL on the ML view, it is located in the right, lower, outer quadrant.
One useful mnemonic in localizing breast masses is "lead falls and muffins rise." A mass located laterally on the CC view will actually be lower in the patient than predicted by the MLO view. A mass located medially on the CC view will actually be higher in the patient than predicted by the MLO view (Figure 12).
In this technique, the MLO view is placed in the center and the CC view is placed on either side with the nipple at the same level and pointing in the same direction (Figures 13 and 14).