6.2 The Mask

6.2.1 Creating a new structure and mask

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Functionality is available in the Pro edition
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  1. Click the Add a new structure PIC button. The dialog shown in Fig. 6.4 appears.


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    Figure 6.4: Set mask for a new structure


  2. Enter the name of the new structure in the Name field. By default, the name of the structure is automatically generated by the <Structure X> template, where X is the counter with the increment of one point. The first value is 1.

  3. Set the tissue density values for the mask. You can do it in one of the three ways:

  4. Click OK to create a new structure and mask or CANCEL to cancel.

6.2.2 Changing the structure mask using CLUTs

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Functionality is available in the Pro edition
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You can change the mask of the current structure in several ways:

  1. Using the Adjust W/L tool:

    1. Select the target structure on the panel of segmented structures.

    2. Click the Adjust W/L PIC button on the toolbar.

    3. Change the window width and level for the editing mask (see Section 2.17). The green editing mask changes in real time in the MPR window.

  2. Selecting the color table from the dropdown list (see Section 2.22.1) or with the Custom W/L PIC tool (see Section 2.17).

  3. For the properties tree on the Segmented structure panel (Figure 6.5):

    1. Unfold the list of the segmented structure properties.

    2. In the drop-down list, select the editing mask mode or the color table you need:

      • The High intensity and Low intensity mode provides the editing mask for tissues whose density is above or below the threshold value.

      • The Interval mode provides the editing mask for tissues whose density is within the set value range.

      • The CLUT mode provides the editing mask for the tissues displayed for the chosen color table.

    3. To change the interval or the density threshold, click with the left mouse button on the values (see the red box in Figure 6.5). Provide the values you need and press Enter key on the keyboard.


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    Figure 6.5: Editing the mask


    The editing mask parameters (the color table, the intensity threshold value and the interval) are changed for each segmented structure separately. The color table type and the editing mask mode for the segmented structure selected is shown on the visualization setup panel.

  4. For the Volume Reconstruction window only: using the Set mask tool (see Section 6.2.4).

You can change the editing mask visibility for the current structure using the editing mask setup panel (see Section  6.2.3).

6.2.3 The Editing mask

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Functionality is available in the Pro edition
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The editing mask is a pattern beyond which the structure mask is not visible.

The editing mask is not visible in the volume reconstruction window, and it is displayed in green in the MPR window. If necessary, the editing mask can be inverted. In this case, the tissues not under the editing mask are displayed in green. To invert the editing mask, set the flag Invert edit mask on MPR (see Section 16.7.3).

The editing mask can be changed at any time (see Section 6.2.2). If the editing mask is reduced and the structure goes beyond the editing mask, then this part of the structure becomes invisible and is not taken into account in the calculations. However, it is not removed and when the editing mask is increased, it becomes visible again.

You can change the editing mask visibility for the current structure using the editing mask setup panel (Fig. 6.6). The panel is placed at the bottom of the segmented structures panel and is only available in the MPR reconstruction tab.


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Figure 6.6: Editing mask panel


There are two ways to change the visibility of the editing mask:

The editing mask opacity value is expressed as a percentage.

To see the outline of the editing mask, check the Outline box.

To conceal the editing mask, click the Hide mask PIC button on the editing mask setup panel. To display the editing mask, click the Show mask PIC button.

The Hide mask PIC button is unavailable if at least one tool for segmentation or volume editing has been activated.

To minimize the editing mask setup panel, click the Hide PIC button. To display the hidden panel, click the Show PIC button.

6.2.4 Set Mask Tool

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Functionality is available in the Pro edition
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The tool is only available for the Volume reconstruction tab. To set a structure as a mask for another structure or base volume, proceed as follows:

  1. On the list of structures, select the structure (base volume) for which you want to change the mask.

  2. Click on the Set Mask PIC button. The dialog shown in Fig. 6.7 will be displayed.

  3. On the list of structures, select the structure (base volume) you want to set as the mask.

  4. Click OK to confirm or CANCEL to cancel the action.


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Figure 6.7: Select mask dialog