3D View

The 3D View is the most powerful feature of the VisioVIEW CT Viewer that allows users to visualize and interact with the volumetric DICOM data. Activate the 3D View by selecting the MPR + 3D View option from the left toolbar, or select the View -> 3D option from the viewer menu.

The 3D View provides a virtual 3D reconstruction of the scanned object, allowing users to rotate, zoom, and manipulate the 3D model for better understanding and analysis.

Orientation the 3D Object

Upon switching to the 3D View, the 3D model is reconstructed and visible in the left split of the viewer, while on the right, the three MPR views are represented.

Rotation of the 3D Volume

To rotate the 3D volume, select the Select/Move Item tool and assign one of the available mouse buttons to it. Press and hold on the volume to initiate the rotation, and drag the mouse in the desired direction to rotate it.

The 3D orientation cube displayed in the bottom right corner indicates the current position of the planes.

The sides of the cube are referring to the RAS coordinate system: A (Anterior), P (Posterior), L (Patient Left), R (Patient Right), S (Superior), and I (Inferior).

Alignment of the 3D Volume

For precise alignment of the 3D volume object to one specific side, press the appropriate letter representing the desired side in the bottom section of the viewer.

Users can also adjust the range of slices visible from each plane. By default, the entire 3D volume is loaded in the viewport. Modify and cut the volume by using the three available sliders in the bottom section of the viewer.

To adjust the transparency of all slices in the 3D model simultaneously, drag the Alpha Value slider in the desired direction. The default transparency of the CT Viewer is represented on the right image, while the left image represents a fully opaque 3D volume.

Render Modes

Render modes are visualization techniques used to display the volumetric DICOM data, each offering a unique way to interpret the internal structures.

There are three render modes available to visualize the 3D volume.

• Ray - Color: Creates the 3D volume based on the HU (Hounsfield Unit) values of each voxel of the body and assigns specific colors to it.

• Ray - Gray: It uses the exact same principle as the Ray - Color render more, however it assigns grayscale shades rather than colors to the voxels.

• Iso Surface: Generates a 3D surface that represents the volumetric DICOM data, highlighting the exterior and specific structures of the body.

3D Windowing

The windowing of the 3D volume is applied in the same way that the windowing for MPR is applied, however they are separated so that they do not interfere with one another. Read more about how to modify the windowing in the following section.

HU Distribution

HU distribution provides a visual representation of the range and distribution of tissue densities within the 3D volume. Users can assign different colors or color ranges to visually distinguish and examine the tissues based on their density.

The HU distribution is represented by a histogram, which displays the frequency of voxels in the volume at each specific HU value. The HU values range from -1000 to 3000.

HU Distribution Panel Interface

The vertical axis of the histogram represents the voxel count while the horizontal axis displays the available range for the HU values. The histogram also displays the actual color distribution of the HU units.

The endpoints of each color range can be assigned to different colors. If the colors at each endpoint are different, the range will consist of a linear gradient between the two colors. Additionally, the gap between two endpoints of different ranges will also be filled with a linear gradient of those colors.

The default tissue HU ranges for the VisioVIEW CT Viewer are automatically set and represented in the table below the histogram.

Modify Color Ranges

To move an entire color range on the histogram, hover over the range, press it and start dragging the line in the desired direction.

To increase or decrease ranges press and drag the endpoints of the range in the desired direction.

If two HU ranges overlap, the overlapped area becomes invalid and inactive. The invalid ranges are indicated by the mesh pattern on the histogram, red border on the endpoints of the ranges and the red highlighted values in the table.

Modify the individual color of each endpoint of the range by double-clicking on the specific endpoint. To modify an entire range at once, double-click on the range line itself, or double-click on one of the entries below.

Modify Individual Colors

The color of each endpoint on the range can be individually updated by choosing an option from the Select Color dialog. Users have the ability to choose from a preset of available colors, choose a color from the color picker on the right or select the Pick Screen Color option to select a color available somewhere on the screen.

Additionally, users can manually set the Hue, Saturation and Value parameters to define a color in the HSV color system, set the Red, Green, and Blue channels to define a color in the RGB color system, or specify its hexadecimal value in the field.

The current active color can also be added and saved to the custom colors for future reference and usage. Press the Add to Custom Colors button to save the active color.

Confirm the changes and close the dialog by pressing OK, or cancel any modifications by pressing Cancel.

Edit Color Ranges Dialog

Modify the name of each range by using the Edit icon next to the current name of the range.

The dialog offers the possibility to edit each endpoint of the range individually. The starting HU value and color for the range can be specified in the HU Range - From section, while the end HU value and color for the range can be specified in the HU Range - To section.

The color of each endpoint can be individually chosen by pressing on the selected color for the endpoint, which opens the aforementioned dialog. To modify the opacity of each color in the endpoint, drag the slider below the color in the desired direction.

To specify the same color as the starting and end point of the range, press the Link icon between the two colors. The colors can be unlinked by toggling the same button again.

Confirm the changes to the range by pressing OK, or cancel the dialog by pressing Cancel.

Add New Color Range

Add a new color range by double-clicking on the histogram at the desired HU value indicated by the vertical line hovering over it. The starting HU value and color will be set based on the chosen position in the histogram.

Users can also add new colors ranges by using the Add New Color button. Both cases open the same Edit Color Range dialog as before, with a different purpose.

Modify and Delete Ranges from the Table

Edit an entire color range by using the Edit icon when hovering over the selected entry in the table.

To delete a color range from the table and the histogram itself use the Delete icon when hovering over the selected entry in the table.

Preset Options

• Save as Default: Save the modified HU distribution as the default preset used throughout the VisioVIEW software when usin the CT Viewer. Choose the Defaults -> Save as Default option from the drop-down menu at the bottom of the dialog.

• Load Saved Default: Reset any active changes to the HU distribution by loading the last saved default. The Defaults -> Load Saved Default option from the menu is disabled if there was no preset saved before.

• Load VisioVIEW Default: Load the factory HU distribution of the VisioVIEW software by using the Defaults -> Load VisioVIEW Default option.

Confirm all of the changes in the HU distribution by pressing the OK button. Discard any pending changes by pressing the Cancel button.