Preparation Scans Related To Regular Bold Sequences - Siemens Prisma 3T User Manual

Preparation Scans related to Regular BOLD Sequences

1. To ensure that a steady-state magnetization is achieved when multiple averages or
measurements are acquired, a number of preparation scans are performed at the start of
the measurement
2. The number of preparation scans is set within the sequences, and chosen so that the
preparation time is longer than 3 seconds
 TR = 500 ms 7 preparation scans
 TR > 501 ms 6 preparation scans
 TR > 601 ms 5 preparation scans
 TR > 751 ms 4 preparation scans
 TR > 1001 ms 3 preparation scans
 TR > 1501 ms 2 preparation scans
 TR = 2000 ms 2 preparation scans
 TR = 2500 ms 2 preparation scans
 TR = 3000 ms 2 preparation scans
 TR > 3001 ms 1 preparation scan
3. The preparation scans result in a longer scan time for the first measurement in a time-
series acquisition, which should be taken into account when performing BOLD imaging
4. The sequence does not send external trigger pulses when performing these preparation
scans, so that they do not have to be considered when triggering external devices for
stimulus presentation in BOLD imaging studies
5. This formula does not apply to multiband bold sequences
6. Turning iPAT on will add 1 additional prep scan
7. Turning introduction "on" will add 1 additional prep scan
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Revision Date: 3/13/2019