Siemens MAGNETOM Avanto Operator's Manual page 96

4 Physiological imaging
Trigger methods
Disposable electrodes
96
The positions of the ECG leads shown here are examples only. The
best position for the electrodes must be decided for each patient
individually.
The two leads I and II are used and acquired in parallel via the ECG
channels. Both curves display a prominent R wave when the ECG
electrodes and leads are correctly attached.
The characteristic QRS complex of the ECG signal is used as trigger
signal. Simultaneous acquisition and overlaying of the orthogonal
leads (vector cardiography = VCG) is used to minimize triggering
errors due to gradient switching and the magneto- hydrodynamic
effect (i.e., excess T-wave amplitude).
In the dialog box of the Physiological display several trigger
methods are available:
◾ VCG standard: VCG activated
◾ ECG I: VCG inactive
◾ ECG II: VCG inactive
◾ Auto: Improved trigger algorithm; VCG activated; default trigger
method
If Auto is used, the signal characteristics can be relearned by
selecting Relearn in the context menu of the Physiological display.
If triggering with Auto fails, preferably VCG standard should be used.
For ECG triggering, special MR Conditional and disposable electrodes
are used (the recommended ones are available through the
Accessories catalog).
MR System | Operator Manual
Print No. MR-01501G.621.02.02.02