Projektionsebenen Mammographie

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There are numerous mammography views that can broadly be split into two groups

  • standard views 
  • supplementary views - additional information or problem solving

    • Standard views

    Standard views are bilateral craniocaudal (CC) and mediolateral oblique (MLO) views, which comprise routine screening mammography. The views are usually used for all routine screening clients. That is, unless there is a contraindication, screening mammograms consist of these 4 views.

    Not all 4 views are always performed in all mammogram studies.  For instance, in clients under 40 only 2 MLO views may be done to limit radiation exposure, depending on local policy and the discretion of the radiologist.

    In cases of recent surgery limited imaging may also be appropriate. Where a patient has painful breast pathology or large lesions or an abscess, imaging should be tailored to specific cases and is usually only done after consultation with the radiologist. Common sense should prevail.

    MLO versus ML 

    The reason is that a mammogram is a two dimensional representation of a 3 dimensional structure; by the same token a map is not an accurate representation of the earth's actual geography. The ML view loses significant tissue volume in the upper outer quadrant of the breast where statistically the most breast cancers are found. By doing an MLO view you get extra tissue without extra exposure. The downside of the MLO view is it is not 90 degrees to the cc view so localization of a lesion requires some thought. The two views are not orthogonal.

    Additional (supplementary) views

    These views are used in diagnostic breast workups in addition to the standard views.

    When to use which view 

    As a general rule, parenchymal asymmetries are worked up with straight lateral (SL) and rolled CC (rolled) views. Calcifications are worked up with magnification views (mag views). The degree of roll does not have to be very significant in most cases. All you are trying to achieve with SL and rolled views is to separate summation shadows from each other. Very often a summation shadow seen on an MLO view will disappear if the very same view is immediately performed.

    In practice, additional views are always followed by ultrasound if there is a positive finding. The converse is true as well. When doing diagnostic work up on a breast do not be tempted to skip the additional views or the ultrasound. They each add value.

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