Quick Visualization of Aneurysms

Please Review

This tutorial will attempt to guide you through a specific set of functions within VIDA step by step while by-passing an in depth explanation of the multitude of capabilities for each specific module. If you wish to find a more detailed discussion of any of these modules, please click on the smiling face and "have fun."

Start VIDA

Type vida_start.

Loading Scan

If the image data is not on your computer, you will need to transfer the data to disk before you can load it into shared memory. For more explicit instructions, please see the Tape Utilities section.

Loading Data into Shared Memory

To use VIDA's Volume Render Program, you must first load the image data into shared memory.

Maximizing Contrast

To maximize the contrast of the structures within the brain, you will want to find and load the grey scale values of the blood vessel and its immediate surrounding tissue. Using the LAF:Sample panel, draw a box in the brain. Using the histogram, determine the minimum and maximum grey scale values. Next, using the LAF:Properties panel, type in the desired Scale Max value and press return (the desired maximum should be the LAF:Sample maximum(i.e. 353) + (100 to 150)). Then type in the desired Scale Min value and press return (the desired maximum should be the LAF:Sample minimum (i.e. -33) - (100 to 150)).

Loading in a Subregion

Using the LAF:Sample panel, draw a box in the brain containing the subregion you want to investigate. Determine which image slices and what area should be loaded. Once you have properly boxed the subregion, press the Set Options button. Then using the LAF:Properies panels,determine and set the slices you want to view.

Loading a Subregion Containing the Circle of Willis

Using the slice slider on the LAF:Sample panel
  1. Using the left mouse key button, draw a box which will encompass the middle of the brain including the area of the Circle of Willis, the Anterior Cerebral Arteries, the Basilar Artery, and at least a small portion of both Posterior Cerebral Arteries.
  2. Using the LAF:Sample slice slider, go up and down through the data set making sure as little as possible bone appears in the boxed area.
  3. If you want to redraw the subregion box, press the Clear button.
  4. If the box is drawn properly, press the Set Options button.

Using the LAF:Properties panel

  1. Select the Slider Control Z button
  2. Set the Start slider to the first slice you want to load (i.e. 5)
  3. Set the Number slider to the number of slices you want loaded (i.e. 65 to load slices 5 to 70)
  4. If your data set is 16 bit convert it to 8 bit by clicking on the 16 to 8 bit check box
  5. Make sure you entered the proper Scale Max and Scale Min values -- review how to

Loading a Subregion Containing Right Internal Carotid Artery

Using the slice slider on the LAF:Sample panel
  1. Using the left mouse key button, draw a box which encompasses the right internal carotid artery and part of the right middle cerebral artery with as little as possible of the bone and the basilar artery.
  2. Using the LAF:Sample slice slider, go down and up through the data set making sure that as little as possible bone appears in the boxed area
  3. If you want to redraw the subregion box, press the Clear button.
  4. If the box is drawn properly, press the Set Options button.

Using the LAF:Properties panel

  1. Select the Slider Control Z button
  2. Set the Start slider to the first slice you want to load (i.e. 5)
  3. Set the Number slider to the number of slices you want loaded (i.e. 65 to load slices 5 to 70)
  4. If your data set is 16 bit convert it to 8 bit by clicking on the 16 to 8 bit check box
  5. Make sure you entered the proper Scale Max and Scale Min values -- review how to

Loading a Subregion Containing the Basilar Artery

Using the slice slider on the LAF:Sample panel
  1. Find the image slice where the Posterior Cerebral Arteries branch off the Basilar Artery.
  2. Using the left mouse key button, draw a box which will encompass the Basilar Artery and at least a small portion of both Posterior Cerebral Arteries.
  3. Using the LAF:Sample slice slider, go down and up 20 to 30 slices making sure that no bone appears in the boxed area
  4. If you want to redraw the subregion box, press the Clear button.
  5. If the box is drawn properly, press the Set Options button.

Using the LAF:Properties panel

  1. Select the Slider Control Z button
  2. Set the Start slider to the first slice you want to load (i.e. 15)
  3. Set the Number slider to the number of slices you want loaded (i.e. 55 to load slices 15 to 70)
  4. If your data set is 16 bit convert it to 8 bit by clicking on the 16 to 8 bit check box
  5. Make sure you entered the proper Scale Max and Scale Min values -- review how to

Loading One Side of the Brain

Using the slice slider on the LAF:Sample panel
  1. Using the left mouse key button, draw a box which encompasses one side of the brain and as little as possible of the bone.
  2. Using the LAF:Sample slice slider, go down and up through the data set making sure that as little as possible bone appears in the boxed area
  3. If you want to redraw the subregion box, press the Clear button.
  4. If the box is drawn properly, press the Set Options button.

Using the LAF:Properties panel

  1. Select the Slider Control Z button
  2. Set the Start slider to the first slice you want to load (i.e. 5)
  3. Set the Number slider to the number of slices you want loaded (i.e. 65 to load slices 5 to 70)
  4. If your data set is 16 bit convert it to 8 bit by clicking on the 16 to 8 bit check box
  5. Make sure you entered the proper Scale Max and Scale Min values -- review how to

Previewing What you are about to Load

If you want to preview what you are about to load, using the LAF:Preview panel, press the loop button to view the image as it will appear after being loaded. For more explicit information on loading data, please see the Loading Image Data section.

Visualizing Cerebral Blood Vessel

Display Colors and Contrast

To enhance your ability to view the cerebral blood vessels, you may wish to change the display colors. We suggest you select heat or Grey_Screen from the Color Scales menu. For more explicit instructions, please see the Color Scales section. You may also find changing the Window and Level parameters useful for visualization.

Volume Rendering the Vessels

To call up the Volume Render module:

Maximum Intensity Projection

On the VR: Rendering Parameters panel
  1. Press the right-mouse key on the Render Style triangle menu button
  2. Select Brightest Pixel from the menu
  3. Press the Render button at the bottom of the screen
  4. A 3-D representation of the vessels should appear on the Volume Render (VR) panel canvas
  5. Use the X, Y, and Z Rotation Sliders on the VR: Rendering Parameters panel, to obtain the orientation you want

Shaded Surface Display

On the VR: Rendering Parameters panel
  1. Press the right-mouse key on the Render Style triangle menu button
  2. Select Gradient Shading from the menu
  3. Using the Color Bar on the Color Scales panel, determin the Minimum and Maximum values of the vessels.
  4. Type the minimum and maximum values on the Threshold Min and Threshold Max entry lines of the VR: Rendering Parameters panel
  5. Press the Render button at the bottom of the screen
  6. A 3-D representation of the vessels should appear on the Volume Render (VR) panel canvas
  7. Use the X, Y, and Z Rotation Sliders on the VR: Rendering Parameters panel, to obtain the orientation you want

Making a Movie of the 3-D Projection

  1. Press the right-mouse key down on the edit menu button on the Volume Render (VR) panel
  2. Drag the cursor down to the Movie Maker menu item
  3. Release the right-mouse key to select the Movie Maker menu item
  4. The VR:Movie Maker panel should appear
  5. Using the X, Y, and Z Increment sliders, detemine how many degrees rotation you want each frame of the movie to increment by
  6. Type the number of frames on the Number of Frames entry line
  7. If you want to save the movie to a file, left click on the Destination check box and type a file name on the File Name entry line
  8. Press the Apply Button

Example Movies

Circle of Willis -- Maximum Intensity Projection

This movie was created by loading the area containing the Circle of Willis. Volume Rendering was done using the Brightest Pixel algorithm. The movie starts with a coronal view with the patient facing you; the patient's head with the patient's right on the left side of the MPEG viewer. The projections are rotated at 10 degree increments about the y axis toward the patient's right.

Circle of Willis -- Shaded Surface Display

This movie was created by loading the area containing the Circle of Willis. Volume Rendering was done using the Gradient Shading algorithm. The movie starts with a view from the top of the patient's head with the patient's right on the left side of the MPEG viewer. The back of the patient's head is at the bottom of the MPEG viewer. The projections are rotated at 10 degree increments about the X axis. Frame 10 corresponds to a coronal projection with the patient facing you; the patient's right is on the left side of the MPEG viewer.

Basilar Artery -- Maximum Intensity Projection

This movie was created by loading the area containing the Basilar Artery. Volume Rendering was done using the Brightest Pixel algorithm. The movie starts with a coronal view. The projections are rotated at 20 degree increments about the y axis. Frame 1 corresponds to a coronal projection with the patient facing you; the patient's right is on the left side of the MPEG viewer.

Basilar Artery -- Shaded Surface Display

This movie was created by loading the area containing the Basilar Artery. Volume Rendering was done using the Gradient Shading algorithm. The movie starts with a coronal view. The projections are rotated at 10 degree increments about the y axis. Frame 1 corresponds to a coronal projection with the patient facing you; the patient's right is on the left side of the MPEG viewer.

Right Internal Carotid Artery -- Maximum Intensity Projection

This movie was created by loading the area containing the Right Internal Carotid Artery. Volume Rendering was done using the Brightest Pixel algorithm. The movie starts with a coronal view. The projections are rotated at 10 degree increments about the y axis. Frame 1 corresponds to a coronal projection with the patient facing you; the patient's right is on the left side of the MPEG viewer.

Right Internal Carotid Artery -- Shaded Surface Display

This movie was created by loading the area containing the Right Internal Caroitd Artery. Volume Rendering was done using the Gradient Shading algorithm. The movie starts with a coronal view. The projections are rotated at 10 degree increments about the x axis. Frame 1 corresponds to a coronal projection with the patient facing you; the patient's right is on the left side of the MPEG viewer.

Right Hemisphere -- Shaded Surface Display

This movie was created by loading the right hemisphere. Volume Rendering was done using the Gradient Shading algorithm. The movie starts with a transverse view and ends with a coronal view of the patient facing you; the patient's right on the left side of the MPEG viewer. The projections are rotated at 5 degree increments about the x axis.

VIDA Tutorial Sections Relevant to the 3-D Visualization of Brain Aneurysm Tutorial

 You may find it helpful to review the relevant VIDA tutorial sections.
Tape Utilities
Loading Image Data
LAF:Sample
LAF:Properties
LAF:Preview
Color Scales
Volume Renderer
VR:Select Volume
VR:Rendering Parameters panel
VR:Movie Maker panel
Movie Viewer




©1994-98 Division of Physiologic Imaging, Dept. of Radiology, Univ. of Iowa


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Last modified: Tue Jun 23 10:39:23 CDT