tangential views

Tangential views are useful to differentiate intracutaneous radiopaque particles in a tattoo from intraparenchymal microcalcifications.

Mammographic findings close to the skin such as masses, microcalcifications, skin dimpling or shaded areas always pose a problem of differential diagnosis.

Various different methods have been described for further assessment of these questionable findings: Berkowitz et al. and Bassett both suggest the use of a grid to place a radiopaque marker over the area assumed to contain the finding prior to obtain a second, orthogonal view  to confirm that the finding is located directly in the area of the marker.

The cons of this method are the long time that patient's breast remains compressed until the marker has been placed on the skin (which may involve several minutes of uncomfortable compression) and the risk of obscuring the finding by the radiopaque marker in the second view (the use of a felt-tip would avoid this problem). Furthermore, the real goal should be to reduce the amount of overlapping tissue for better margin differentiation.

The easiest and most effective method to show the location of these findings in the skin is the following: at first, the questioned area is localized in one plane using a grid and marked in this plane with a felt-tip pen. Then the breast is rotated to a obtain a second view tangential to the point thus marked on the skin.

Siehe auch:

• Projektionsebenen Mammographie