Inversion Timing; User Resp Setup Window - SA Instruments 1030 Operation Manual

Inversion timing

For certain imaging sequences, such as inversion recovery, the image data is acquired
at a time later than the start of the pulse sequence. In those cases it may be desirable
to generate a delayed gate to make certain the image is acquired at a specific position
in the cardiac and/or respiratory cycle.
Parameters for the inversion timing calculation are entered from an expanded GATING
SETUP window implemented by clicking the Inversion Timing key in the GATING
SETUP window.
Consider a pulse sequence which applies a RF pulse 1400ms before readout of the
image data. If the detected R-wave peak generates a gate to initiate the pulse
sequence and thus the RF pulse, the image data will be acquired 1400ms later at a
position in the cardiac cycle which depends on the heart rate or R to R period. For the
example shown on the preceding page, the image would occur 35ms after a later R-
wave peak assuming the heart rate does not change.
To position the image at the beginning of the cardiac cycle (at the R-wave), we perform
an inversion timing calculation where the calculated gate delay plus the inversion time is
the first integer multiple of the R to R period. For the example shown where the
inversion time is 1400ms and the R to R interval is 105ms, the smallest integer which
when multiplied by the R to R interval exceeds the inversion time is 14. In this case the
calculated delay is 70ms (70ms + 1400ms = 14*105). Since the calculation is made on
the fly, the calculated delay will automatically change with animal heart rate to ensure
the image data is collected at the same position in the cardiac cycle.
The inversion timing delay calculation can be applied to ECG, respiration or both. The
Pulse Invert, Begin Delay and Max Width controls are active during the calculation.
Make the desired changes to these parameters, input the inversion time and click the
On/Off key. Within 2 seconds, the delayed gate should appear on the monitor display
and be output from the ERT Control/Gating Module.

USER RESP SETUP window

Right click on the User Resp waveform to open the USER RESP (USER SPARE RESP)
SETUP window.
The following items can be set from the USER RESP window:
1. Labels for both waveform and scale
2. Scaling,
3. Offset,
4. Scale adjust step size
5. High pass filter,
6. The flashing LED on the IBP Module
7. Signal gain
Revision C, August 2013
Advanced Features
15-3