The bridge option lets you separate small tissue volumes from the main tissue body by specifying the minimum number of pixels that any two bodies need to be connected with. The main tissue body is where the seed point is placed. You can use the bridge option instead of, or in conjunction with, outside points.
Outside points: Specify an area within an image that needs to be disconnected from the main tissue body.
Bridge: Acts on the entire image. For example, a bridge value of 4 means "disconnect any tissue mass that is connected to the main tissue body by less than 4 pixels."
1. From the Tissue Definition toolbar, click Tissue Definition Parameters 
.
The Tissue Parameters dialog box appears.
2. Enter a bridge value or use the arrows to select a bridge value in the Bridge field.
3. Click OK.