Click Group Layouts 
to choose a Display Option presenting a Fusion Image, such as Two Datasets + Fusion 3x3 or Two Datasets + Fusion 1x3.
In a Fusion Image, the two displayed data sets are superimposed (or fused) to create the fusion content. To change the fusion content, replace one of the data sets.
One study in the Fusion Image is considered the Primary and the other as Secondary. You can separately control each study in the fusion image. For example, you can apply windowing or measurements.
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