The Aorta Protocol is used for tracing the aorta and iliac arteries. The system provides you with a set of basic points, relating to specific parts of the vessel path, including the start point, bifurcation point, right iliac, left iliac, and end point.
1. In the Archive Explorer, right-click the study you want to view, select Load To, then select Vessel Analysis.
2. In the Vessel Analysis toolbar, click New Vessel 
.
3. Select Aorta Protocol.
Mark Point 
appears on the toolbar. You must select Mark Point each time you want to add new points.
4. Click Aorta Protocol.
The Aorta Protocol dialog box appears.
5. Click the start point on any of the MPR reference images.
Start of Section is checked and Start is marked on the image. If necessary, you can scroll the MPR reference images to view the required location.
NOTE: You can mark any extra points or occlusions between the start and end points by holding down the Shift key (for extra points) or the Ctrl key (for occlusions) while clicking the image in the required positions.
6. Click on a point to define the Aorta Bifurcation.
The Aorta Bifurcation option is checked and Bifurcation is displayed on the image. You can skip this point and select to mark another point by selecting the point you want to mark in the protocol dialog box. You can mark the skipped arteries at a later stage.
NOTE: You can remove the last point you clicked by clicking the Delete Last Point button.
If you reopen the protocol at a later stage, you will be instructed to mark only the sections that were skipped. When the missing points are marked, the new vessels will be joined to the vessels that already existed.
7. Mark a third point at the end of the left iliac artery.
The Left Iliac Artery option is checked. Left Iliac is displayed on the image.
8. Mark a fourth point at the end of the right iliac artery.
The Right Iliac Artery option is checked. Right Iliac is displayed on the image. The Aorta Protocol window appears.
To mark the intermediate points (the points between the start and end points) in a different order (for example, the left iliac artery before the bifurcation point), select the relevant row in the Aorta Protocol dialog box, then mark the point on the image.
If you do not want to mark both the left and right iliac arteries, you can mark either one, then mark the other one later. Select New Vessel, then select Aorta Protocol, then mark the other vessel.
If you do not mark one of the named points, the next time you open the Aorta Protocol dialog box for that vessel, the row of the unmarked point will be selected and ready for marking.
9. Mark a fifth point at the end of the left iliac artery, if desired.
10. Click Done 
.
A message appears while the vessel is being calculated. Once the vessel has been calculated, additional Vessel menu and toolbar options are displayed.
NOTE: The end points do not have to be marked at the very end of the arteries. You can decide where to end the vessel tracking.
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