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Welcome to the CMRR MB-EPI C2P sequence wiki!

The intent of this section is to provide additional documentation and supporting tools for "advanced" users.

Physiology log file format

• Sample code for reading the new physiology log files [MATLAB, Python]
• Support for reading the physiology data is also integrated in the BIDScoin toolbox

Extra shadowy shadow header parameters

Diffusion

In the "Phoenix" shadow header (text protocol), the following diffusion parameters are recorded (these are otherwise shown in a tooltip when editing a protocol):

• sSpecPara.dSpecLipidSupprBandwidth: small delta (for monopolar scheme only)
• sSpecPara.dSpecLipidSupprDeltaPos: big DELTA (for monopolar scheme only)
• sSpecPara.dSpecWaterSupprBandwidth: estimated b-value of spoiler gradients (played for "b=0" scans)

MB RF phase scrambling

• sIR.adFree[]: the inter-band phase offsets used if MB RF phase scrambling is enabled

Advanced sequence options

• Some advanced sequence options can be unlocked by creating and editing a file named MBAdvancedSettings.ini in the customer sequence directory. This file uses the basic Windows ini-file syntax.

  Use these options at your own risk!

  • User-specified slice-GRAPPA kernel size

        [MultiBand]
        ManualGRAPPAKernelSize = 1
    

    Note: By default, the slice-GRAPPA kernel size is determined automatically. Enabling this ini-file option will unlock an option in the protocol UI for specifying the slice-GRAPPA kernel size on a per-protocol basis. Please refer to the UI tooltip for further details.

  • User-specified FoV shift factor (blipped-CAIPI, CAIPIRINHA)

      [MultiBand]
      ManualBlipFactorSL = 1
    

    Note: By default, the FoV shift factor is determined automatically. Enabling this ini-file option will unlock an option in the protocol UI for specifying the FoV shift factor on a per-protocol basis. Please refer to the UI tooltip for further details.

  • Slice multiplier factor (workaround for 128-slice limit of UI)

      [MultiBand]
      SliceMultiplier = 1
    

    Note: This option will automatically increase the number of acquired slices by the specified factor, otherwise keeping the slice FoV, TR, etc. constant. For example, to acquire 180 1mm slices, prescribe 90 2mm slices and set this parameter to 2. If the Mosaic matrix size limit is exceeded (4096x4096 on UHF; 2048x2048 otherwise), reconstruction will crash. This option is only unofficially supported for VB17A/UHF.

  • Allow "forbidden" options (R017 and newer)

      [MultiBand]
      AllowForbiddenOptions = 1
    

    Note: This option will open up options in the UI for features that are considered unstable. Be very careful when using this option: the "forbidden" options are disabled by default because they are strongly suspected of causing system instability—including but not limited to producing incorrect data, crashing the scanner, etc.

  • Ignore clipped RF pulse warning

      [SeqDebug]
      IgnoreRFClipping = 1
    

    Note: This option will globally disable the "clipped RF pulse" warning popup. It is strongly recommended to not disable this popup, since multi-band pulses can easily exceed the available transmitter voltage, and in this case the system will silently run the acquisition at maximum voltage, which may yield a much lower flip angle than expected. Only use this option for testing, e.g. on UHF pTX systems.

• Additional variant-specific advanced sequence options can be unlocked by creating and editing files named cmrr_mbep2d_bold.ini, cmrr_mbep2d_diff.ini, and cmrr_mbep2d_se.ini in the customer sequence directory. Settings added to these files will only apply to the named sequence variant. These files use the basic Windows ini-file syntax.

  Use these options at your own risk!

  • User-specified minimum base resolution (allowed values: 32-64)

        [Limits]
        MinBaseResolution = 32
    

    Note: By default (since R016), the minimum base resolution is 64. Any value lower than this seems to cause instabilities in the user interface such as not being able to select FOV phase % values of 100% for certain protocols. A value for this parameter outside of the range [32,64] will not be accepted.