Tracing Anatomic Structures

Before you can trace, you must define the structure. Once you have defined one or more structures, you can trace a structure as follows:

  1. Go to a plane where the structure is visible (use the "-" or "+" buttons on the control panel or type a plane number into the box between these buttons).
  2. Depending on whether you want traces to be open or closed (i.e., whether the trace should connect back to its starting point, from the "Contours" menu, select the "Style" item and then pick "Open" or "Closed" from the submenu. The contous style has no effect on the contours that are saved (you can switch back and forth even once the trace is drawn), but it is disconcerting to see and open trace when you expect a closed one and vice versa.
  3. Using the popup menu at the top of the control panel (the same popup you used to define structure names), select the name of the structure you want to trace
  4. If Tracer is not currently in tracing mode (indicated by red text on the "Trace" button on the control panel), click on the "Trace" button to activate tracing mode
  5. Make sure that the magnification is appropriate and that the entire structure is currently visible by adjusing the magnification and scroll bars
  6. Without pressing the mouse button, move the mouse around on the image in the main window to explore and review the anatomy in the orthogonal views and confirm where you will trace
  7. Move the mouse to the anatomically defined starting point of the structure. Press and then release the mouse button to start tracing at this point
  8. Move the mouse in the direction defined in your anatomic protocol along the anatomic structure. Don't worry about small errors you can fix them later. If you make a grotesque error, you can "shrug off" the bad trace immediately by moving the mouse outside of the main window before you end the trace
  9. Continuous updating of the orthogonal views is suspended while traces are being drawn. However, you can apply the keyboard shortcut for the "Slice" menu's "Update Ortho Views" item while you are tracing to get an updated view corresponding to the current mouse position.
  10. When the trace is complete, end it by clicking the mouse button again
  11. If you want to improve the trace, you can modify it.
  12. You can procede to another plane, or change to another structure to trace on the current plane. It is generally not a good idea to make multiple tracings of a given structure on the same plane, and Tracer will warn you each time you try to do so.

Back to main Tracer page ©2001 Roger P. Woods, M.D.

Modified: December 15, 2001