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Siemens Implementation

Latest compiled FWF sequence versions per IDEA version

VD11D VD13D VE11A VE11B VE11C VE11E XA30A
Version 1.13 1.07 1.07 1.05 1.26 1.19 1.34

If any given IDEA version is not in the table, we have not yet developed the sequence for that platform.

Sequence functionallity

The funcitons/capabilities of the shared FWF sequence are intended to support DIVIDE and QTI-style acquisition. The sequence therefore enables:

  • Tensor-valued diffusion encodign with linear, planar and spherical b-tensors
    • The linear b-tensor encoding includes two variants: trapezoids and a x-channel of the spherical variant
    • All waveforms are compensated for concomitant gradients
    • All waveforms are compiled into the sequence and there is no need for a custom waveform library
  • B-values up to 2000 s/mm2
  • Simultaneous multislice (SMS) according to Siemens product implementation (v1.18 and later)
  • All conventional functions of ep2d_diff are maintained (GRAPPA, partial-Fourier, IR-pulses etc.)

More advanced variants of the FWF may be shared/supported in the future!

Sequence file naming convention

The full name of a sequence contains several important bits of information about its version and compatibility. The convention is as follows:

[IDEAVERSION] [*_SERVICEPACK] [_SEQNAME] [_VERSION and VARIANT] [_COMPILEDATE (yymmdd)] [*_COMMENT]

Asterisk denotes optional components.

Example:

VE11C_FWF_V1.13s_190317

This is the standard FWF sequence compiled 17th March, 2019 for IDEA version VE11C using no specific service pack. It is the simple variant (variant is "s") version 1.13.

Abbreviated list of version features

  • 1.07
    • Added automatic scaling of waveform in time
    • Added trapezoidal and bi-trapezoidal waveforms to common bank
  • 1.09
    • Added support for storing waveform in DICOM header
    • Fixed error in "AngToRM" rotation mode which did not work properly in 1.07
    • Reworked tooltip to avoid overflow
  • 1.10
    • Added up to 20 study banks
    • Added up to 16 waveform pairs per study
  • 1.12
    • Created simple sequence variant
    • Added hard coded waveforms (LTE, PTE, STE)
    • Diffusion time was maximized along 1st channel (Ch-x)
  • 1.13
    • Re-optimized hard coded waveforms (LTE, PTE, STE)
    • STE is rotated to have the lowest diffusion time along 1st channel (Ch-x)
    • LTE is 1st channel of STE; PTE is independently optimized
    • Added version handling for stored waveforms
    • Experimental removal of 2nd crusher
  • 1.14
    • Developed for non-SMS branch
    • Added user info about flow and acceleration weighting
    • Removed second crusher from s-variant (will be reverted or expanded)
  • 1.15
    • Changed rotation mode for LTE in s-variant to use RM+Sc to be identical to PTE and STE
    • Added control for extended header (will be reverted)
  • 1.16 (buggy)
    • Created "Experimental" variant
    • Harmonization between VE11C and VE11E
    • s-variant always uses crushers (may be expanded)
    • Added trapezoidal LTE to the simple/HC library
    • Moved several function to experimental branch
  • 1.18
    • Added support for SMS (Siemens product)
    • Fixed bug related to new enumeration format
    • Fixed bug related to metadata storage in DICOM header
    • Fixed bug related to update of special seq card tooltips
  • 1.19
    • Added support for asymmeric pause duration
    • Added metadata to DICOM header for absolute timing
    • Added support for HDR export of data
  • 1.22
    • Reworked crusher behaviour (should work well at low-b and self-balance wfs)
    • Added info on motion encoding in the logged "galore" table
    • Reduced maximal amplitude of balance gradient to 2 mT/m
    • Fixed bugg in timing calculation (reduced minimal TE at low b-max)
  • 1.26
    • Started development for in-house development mode
    • Removed DPG mode