GE Revolution CT User Manual page 368

•
Select a recon type that is appropriate for coronary imaging.
•
Poor contrast opacification of the coronary vessels (low or non-uniform HU enhancement
from poor or missed bolus, venous contamination, et cetera) can result in sub-optimal
SnapShot Freeze motion correction.
•
Streak artifacts from surgical clips, pacemaker lead wires, etc., in close proximity to the
coronaries, can result in sub-optimal SnapShot Freeze motion correction.
•
Utilize targeted reconstruction to maximize pixel resolution; however the prescribed DFOV
should allow for at least 2 cm of tissue between the edge of the DFOV and the heart. Do not
"over-zoom".
• As SnapShot Freeze targets coronary motion, for an acquisition series with a scan range
significantly longer than the heart itself, select only the axial scan location(s) containing the
heart to streamline subsequent SSF motion correction processing.
•
Millisecond-based phase prescription and the ECG Editor are fully compatible with
SnapShot Freeze. Utilize as needed.
Prescribe SnapShot Freeze for a Secondary Recon
Use this procedure to prescribe SnapShot Freeze for a Secondary Recon to reduce motion in
the coronary vessels. SnapShot Freeze is only available for single phase and center phase
recon options.
NOTE: SnapShot Freeze is not available for a Primary Recon.
1. From the image monitor, in the
appropriate Secondary Recon task (prescribed as part of the protocol) or add a Secondary
Recon task using [Add a Recon].
2. Click on an existing Secondary Recon task or add a new one to open the editing panel to
the right of the task list.
○
Adjust Thickness and Images per rotation as needed.
○
ASiR-V can be turned "On" by clicking the selection, choosing an ASiR-V level in %, and
then clicking [Apply].
○
Adjust any other parameters as needed.
Anatomy Selection collection to adjust the recon Start Location, End Location,
3. Open the
DFOV, A/P Center offset, and R/L Center offset as needed.
○ The DFOV has to be at least 15 cm.
○
The prescribed DFOV should allow for at least 2 cm of tissue between the edge of the
DFOV and the heart.
ECG and Gating collection.
4. Open the
○
Select SnapShot Freeze to "On".
○
Select Phase Type as needed.
368
Reconstruction and Imaging Processing area, select the
Revolution CT User Manual
Direction 5480385-1EN, Revision 1
7 SnapShot Freeze