R2Star scan protocol considerations

When using Multi-echo FGRE/FSPGR for tissues with short T2* relaxation times, the echo spacing and first echo should be as small as possible (around 1 ms for first echo time) to ensure confidence in the fit of the R2* value. The best way to achieve this is by using a high band width, low matrix, and not using User CV-16, positive gradient polarity.

Consider these tradeoffs as you change scan parameters for images that are post processed with the R2 Star protocol.

• Scan selections: 2D Mode, Gradient Echo family, Multi-Echo FGRE or Multi-Echo FSPGR pulse.
• Adjust scan time to be compatible to the breathold capacity of the patient.
• Typical number of echoes range is 8-16. For IDEAL IQ R2*, 6 echoes are collected.
• TE is automatically calculated to set echo times as short as possible
• If available, select Minimum TE in order to get shorter TE..
• To minimize Fat/Water in-phase/out-of-phase effect with echoes, select Fat Saturation for 2D multi-echo Fast GRE. IDEAL IQ removes this confounding factor per design.
• In patients that have a heavy iron overload, reduce the TE as much as possible to collect enough data points before signal dies off.