Respiratory Gating
495
Curve Editor
The respiration curve editor is used to modify the res-
piratory signal. This editing tool is available after spiral
scan data has been acquired. By using the right mouse
menu on the Trigger tabcard you have access to several
modification tools for the respiratory Syncs (purple
dots above and below the curve), such as Delete, Dis-
able, Insert. In patients with only single or few extra
respiratory peaks caused, e.g. by coughing and sighing
overall image quality may be improved by editing the
respiratory curve prior to reconstruction. Deleting the
corresponding respiratory peaks prevents image
reconstruction in the periods of coughing or arrhyth-
mic breathing. Although respiratory-gated spiral scan-
ning is less sensitive to variable respiratory rates than
respiratory-triggered sequential scanning, the exami-
nation of patients with arrhythmic breathing that
results in unpredictable variations of the respiratory
cycles can result in limited image quality and should be
performed in exceptional cases only.