Known Issues

Pre-op Lengths

When using Preview to assess a patient's anatomy for potential stent
graft repair, it is important to remember that several factors can
impact the accuracy of the measurements made on the scan data. Such as:

  • The quality of the scan data itself,
  • The time that may have passed since the scan was taken,
  • The stent graft being considered
  • The technique to be used in its deployment.

For example, it has been theorized that stiff guide wires can straighten both the aorta and the iliac arteries, and that such straightening can shorten the overall length of the anatomy from the renal arteries to the internal iliac arteries by several millimeters.

If this is true, and if a device with 'hooks' or other fixation mechanisms is used along such stiff guide wire and if the device is deployed rapidly such that the anatomy does not have time to return to normal shape before the attachment mechanisms lock it into place, then the graft may extend farther down the anatomy than anticipated based on pre-operative measurements or virtual graft calculations.

Therefore, use caution when evaluating measurements made on pre-operative anatomy. Be sure to take into account both the type of device and deployment technique you plan to use.

Preview Issues

  • Preview's main interface will sometimes come up 'grayed-out.' Minimizing then maximizing Preview will fix this, and Preview should operate normally.
  • When some virtual graft devices are inserted close to or below the bifurcation of the M2S centerlines, the graft visualization in the model may appear discontinuous.
  • The 82845 Intel Extreme Graphics Video card, common on low-end DELL computers, causes a “color bleed” in the drop slice if you zoom in on the model. This only occurs when looking at the drop slice from the top.
  • On Windows XP with Service Pack 1 installed, some machines may experience graphical anomalies or Preview crashes. If you experience problems running Preview, reduce the video hardware acceleration to disable DirectDraw or contact M2S for assistance.
  • On machines which have had the above fix implemented, users may notice a “color bleed” in the drop slice if you zoom in on the model. This only occurs when looking at the drop slice from the top.
  • Preview will not start if there is a shortcut to the Desktop in the user's My Document's folder
  • The new Virtual Graft(TM) feature can produce grafts with legs that cross through each other or bend oddly under certain situations and with different twist settings. Always review the visualization of the entire graft path carefully to ensure that it represents the situation accurately.
  • The 'Alt' key may disable keyboard short cuts. Hitting ‘Alt’ again or ‘Escape’ will restore keyboard short cuts.
  • Saves in 2.1 and above are incompatible with 2.0 and will not be able to be opened by Preview 2.0.

PC System issues

  • Do not use screen resolution settings greater than 1600x1200. At higher resolutions, the Model image cannot be drawn large enough, and the Jump Slice feature will not work correctly with the Model.
  • If you have problems printing from Preview, select a "Postscript" or "PS" type printer driver, from the pulldown menu in the Print dialog box.
  • Avoid running other large applications when running Preview. If you have problems with slow responses from Preview, or if Preview displays low memory alerts, quit your other applications and restart Preview. If problems persist, restart your machine.
  • Preview requires the color settings for your display to be set to either 16-bit or 32-bit colors. If 8-bit (256 colors) or 24-bit color is used, the Model image will appear with sporadic coloration. 16-bit color provides adequate color, however, it does not allow the Slice images to be shown with their full 8 bits of greyscale. 32-bit color should always be used when possible.
  • Using the "Pointer Trail" feature of Windows can result in small screen rectangles not being redrawn properly. This may be especially noticeable when using the menus in Preview. Some laptops are shipped with the Pointer Trails feature turned on by default. You can use the "Mouse" Control Panel to disable Pointer Trails.
  • On some systems, running other applications, such as Outlook Express or Real Player, while running Preview can cause window drawing to fail in Preview. If the Preview windows draw incorrectly, save your work with Ctrl-S and then quit Preview using Ctrl-X, from the Main Preview Window. Then, restart your computer, and run Preview without the extra applications also running.
  • Preview is optimized for use with the Windows default appearance settings. If text in Preview appears cropped or clipped off, please use the "Display Properties" control panel to set the "Appearance" panel's "Scheme" menu to "Windows Standard" and the "Settings" panel's "Font Size" menu to "Small Fonts". Be sure to use 16 or 32 bit color settings.