The MLO projection images the deep structures in the upper outer quadrant of the breast, where 50% of breast cancers are found.
If it is difficult to perform an MLO projection on a patient with kyphosis, a lateromedial oblique (reverse oblique or LMO) projection may be used. Another possibility is a 90 [degrees] lateromedial projection for the lower half of the breast.
To obtain the standard MLO projection, the patient is positioned as usual.
To obtain the modified MLO, the patient is positioned as for the standard MLO projection. The mammographer then manipulates the breast tissue forward, simultaneously pushing the implant back toward the chest wall.
Some patients positioned for an MLO projection complain about pain when compression is applied.
Obtaining an MLO projection with a male patient is similar to obtaining the MLO with a female patient.
Some patients on stretchers can sit up, making it possible to obtain a standard MLO projection. The back of the stretcher is raised to support the patient and the mammographer positions the x-ray tube assembly parallel to the patient's pectoral muscle.
Breasts with implants usually are evaluated using the standard CC and MLO projections plus modified CC and MLO projections.