Fast Single TR Bipolar Acquisition

Use Fast single TR bipolar acquisition with 2D and 3D FSE family acquisitions that have the Flex imaging option enabled:

• 2D FSE family and either 2D FSE or 2D FSE with Fast Recovery Imaging Option (FRFSE-XL)
• 3D FSE family and Cube

0 = Off.

• In-phase and out-of-phase echoes are acquired in separate TRs. This is most robust against chemical shift artifacts.
• It has no restrictions on frequency resolution, but doubles the scan time and the effective NEX of the sequence.

1 = On.

• In-phase and out-of-phase echoes are acquired in a single TR with bipolar readout. This reduces scan time and minimizes the misregistration problem of the 2-TR mode.
• Fat Shift Direction (FSD) depends on readout direction. When readout direction is reversed, FSD is reversed. For bipolar readout, Out-Phase echo has regular readout polarity, and In-Phase echo has reverse readout. This causes strong chemical shift edge artifacts in the final water image. Limited gradient and bandwidth also limit frequency resolution in this mode.
• To switch to this mode, first increase bandwidth (such as to 100 kHz) and decrease frequency (such as to 128), then set this CV to 1. After that, increase frequency to the desired value and select the recommended bandwidth (displayed at the only entry in the pull-down list).