IMPAX Volume Viewing 3D Visualization & Segmentation

Transcription

1 Getting started guide IMPAX Volume Viewing 3D Visualization & Segmentation This guide outlines the basic steps to perform and manipulate a 3D reconstruction of volumetric image data using IMPAX Volume Viewing 3D. This also includes selectively removing anatomy (e.g. bone) from the rendered 3D volume. These features are only available with the IMPAX Volume Viewing 3D license. Rotating the 3D volume To freely rotate the 3D volume, simply click & drag it with the left mouse button. The volume will then rotate around its centre. Use the mouse scroll wheel to rotate the 3D volume around the viewports vertical axis. To rotate the volume around a user-defined point, single left click on the volume to define the centre of rotation (the crosshairs will be displayed on that point). Then hold the Ctrl key while rotating the 3D volume. You can rotate the volume around a specific axis, using the hot regions next to the orientation puppet. For example, click & drag the HF to rotate the volume around the headfeet axis. To rotate the volume in 90 steps, click & drag the orientation puppet itself. You can also use keyboard shortcuts to set the 3D volume to a fixed orientation: Anterior, Posterior, Left, Right, Head (down), Feet (up) IMPAX Volume Viewing 2.2 LiveLink Node ID page 1 of 5

2 Manipulating the 3D volume Zoom tool 3D projection modes To zoom or pan, select the zoom tool (from the top toolbar or the right-mouse-click menu), and then use the mouse scroll wheel to zoom and click & drag the left mouse button to pan. To change the projection mode of the 3D reconstruction, select another one from the viewport toolbar. The following 3D projection modes are available: DVR (Volume rendering) MIP (Maximum intensity projection) XRAY (X-Ray reconstruction) STEREO3D* (stereoscopic 3D rendering, requires wearing red/cyan glasses) In STEREO3D* mode, the segmentation tools are not available. In this mode, an additional parallax slider is available in the viewport toolbar to adjust the depth impression of the 3D image. * requires the Volume Viewing Plus license. By default, the 3D transfer function will display bone and contrast-filled vessels (for CT datasets). It is possible to interactively adjust the transfer function by click & drag of the middle mouse button (e.g. to visualize skin or muscle tissue). Other predefined 3D transfer functions are available (e.g. to visualize lung tissue) from the viewport toolbar, by clicking the transfer function button. Adjust the clipping planes (grey box) on the MPR viewports to define the 3D cubic volume of interest (VOI). Clipping planes You can rotate the clipping planes by rotating the crosshairs. IMPAX Volume Viewing 2.2 LiveLink Node ID page 2 of 5

3 Segmenting the 3D volume A number of tools are available to add or remove anatomy from a segmentation mask (blue colour). The anatomy can then be removed (sculpted) from the 3D reconstruction. The segmentation tools are found in the top toolbar: Icon Function Show/hide the CT table. Draw a contour on the 3D viewport, and add structures which are outside or inside of the contour to the segmentation mask. Automatically add/remove to/from the segmentation mask. When using these functions, the software will automatically determine the structure by its connected components. Sculpt the segmentation mask. Invert the segmentation mask. This option is used if the inverse of what you wish to remove has been selected. Manually add/remove to/from the segmentation mask. When using these functions, the user has to draw the segmentation mask (by left mouse click & drag). The size of the brush can be set with the slider in the top toolbar. Undo/redo the last segmentation step. Undo all segmentation steps. IMPAX Volume Viewing 2.2 LiveLink Node ID page 3 of 5

4 A segmentation example Select to sculpt the table in the 3D view. Select, and click on the spine (either on the MPR or the 3D view). As a result, a large volume (including the bone and the vessels) will be selected. Select, and click on the vessels to remove them from the segmentation mask. Also click on any other structure which should remain visible (e.g. the kidneys). Then select to sculpt the selected bones in the 3D view. Here, ribs and part of the heart remain in view. For fragment cleanup, use to select the vessels and then use to invert the segmentation mask. All fragments and other unwanted structures (e.g. ribs) will become part of the segmentation mask and can then be sculpted. Use the Sculpt slider in the viewport toolbar to view sculpted structures with adjustable transparency. IMPAX Volume Viewing 2.2 LiveLink Node ID page 4 of 5

5 Segmentation tips & tricks The tools to add or remove parts to/from the segmentation mask can be applied both on the MPRs and the 3D. When automatically adding/removing, better results may be obtained by placing the seed points in the middle of the structure on the MPRs (on the 3D, seed points will be placed on the edge of the structure). The Sculpt slider (to transparently show the segmented structures) only works with projection mode DVR (volume rendering). When automatically adding or removing, only structures which are visible on the 3D viewport will be selected. So by changing the transfer function (e.g. with the middle mouse button), the threshold for this selection can be altered. Before using the segmentation tools, use the clipping planes to focus the 3D reconstruction on the region of interest. After a 3D reconstruction has been segmented properly, save a screen capture of it in IMPAX. This way, the segmentation can later on be restored. A restored segmentation can be further edited and the new result can be saved again in IMPAX. If you want the (blue) segmentation mask to also be displayed on the MPR images, enable the Mask button in the MPR viewport toolbar. Enabling the segmentation mask on the MPRs will automatically set the slice thickness to minimal. IMPAX Volume Viewing 2.2 LiveLink Node ID page 5 of 5