Fig. 25.1
Mammography equipment set up for x1.5 magnification view
Fig. 25.2
Mammography equipment set up for x1.8 magnification view
When selecting the paddle for magnification views, the practitioner should be aware that they are sometimes different to those used for coned compression views. For some manufacturers the paddle for the magnification view has a straight arm.
There are different sized paddles available for use. This allows small and large areas to be focused on appropriately. A small paddle should be chosen for a lesser sized abnormal area, whilst a larger one is reserved for a more extensive abnormality. A larger paddle is used with a lower magnification table, utilising a greater field of view (FOV). An example of the choice of paddles for magnification views are illustrated in Fig. 25.3.
Fig. 25.3
A choice of paddles for magnification views (General Electric)
Coned Compression Views
Coned compression views, or paddle views, are another tool in evaluating an abnormality in the breast following initial mammography. This technique is used typically to improve the characterisation of a mass, an asymmetrical density or a parenchymal distortion that was seen on initial imaging.
Equipment Used
The main tool for compression views is the focal compression paddle. It is important to realise that these may differ from those used for magnification views in that the arm of the paddle is curved (Fig. 25.4).
Fig. 25.4
A choice of paddles for coned compression/paddle views (General Electric)
This allows the paddle to apply focal pressure concentrated on the abnormal area. As with the magnification paddle, there are different sized paddles for coned compression views which allow a smaller or larger area to be focused on. The image is acquired with the breast positioned directly on the usual contact surface (Fig. 25.5).
Fig. 25.5
Mammography equipment setup for coned compression/paddle views
Mammographic Technique
The same mammography procedure applies to both techniques; only the equipment set up utilised is different.
Using the initial mammograms, take a measurement using the integrated digital caliper from the nipple to the abnormality. This will need to be done for each orientation. It is useful to write these details down. Measurements obtained, for example, may be as follows: 4 cm deep to the nipple and 2 cm laterally. This is then transferred back to the client to obtain the same location as that seen on the mammograms. If possible, display the images in the imaging room for reference purposes.
Localising the Abnormal Area (See Figs. 25.6 and 25.7)
Each contact view is uploaded in turn on to the mammographic workstation.
The abnormal area is confirmed by the reporting practitioner.
The linear measuring tool is selected.
A horizontal line is drawn from the nipple posteriorly to the level of the abnormal area. A vertical line (on the image) is then drawn to the abnormality.
Two measurements will be presented on the screen which should be documented for reference (Figs. 25.6 and 25.7).
If two separate further views are required, this procedure should then be repeated for the other projection.
Fig. 25.6
Illustration of lesion localisation measurements in CC projection
Fig. 25.7
Illustration of lesion localisation measurements in MLO projection
Mammographic Technique
The positioning for coned compression and magnification views is similar to that used for routine mammograms. The technique used for the magnification views will require adaptation due to the height of the magnification table and X-Ray tube head.
The practitioner should prepare the imaging room. The correct identifying details must be selected from the work list at the acquisition station. Digital mammography equipment usually acknowledges the magnification table and the specific compression paddles therefore preselecting an automatic exposure, but this should be confirmed.
The vast majority of clients attending for assessment of a perceived abnormality will be anxious and will require sensitive communication. A member of the breast imaging team will need to explain to the client the reason as to why further imaging is required; this should not provoke anxiety or be over reassuring, as this is not in the best interests of the client [9].
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