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3T Multiband: Difference between revisions

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* Flip angle --> [http://www.mritoolbox.com/ErnstAngle.html Ernst angle] A typical T1 value for gray matter @ 3T: 1330 ms (Kruger, et al, 2001).
* Flip angle --> [http://www.mritoolbox.com/ErnstAngle.html Ernst angle] A typical T1 value for gray matter @ 3T: 1330 ms (Kruger, et al, 2001).
* Planning: stevig anguleren. Read-out richting omdraaien AP-->PA?
* Planning: stevig anguleren. Read-out richting omdraaien AP-->PA?
* Equidistant dynamic sampling


== distortion correction ==
== distortion correction ==

Revision as of 12:00, 16 January 2018

Multiband

Sequence-parameters

  • Shimming
    • Shimbox: inside brain? Is bottomline shimbox wrt OFC / air transition most important?
    • What is a good shim?LINEWIDTH checken voor scannen? Log values
    • Acquire extra B0-scan as check to avoid large B0-gradient?
    • Use Maarten's patch for image based shimming: this patch applies shim to B0-prescan
  • TR:
    • for physiological noise correction, aim for 750ms
    • minimal TR: to be adjusted on-scanner (not realistic in VM)
  • Gradient mode: Set to Enhanced if duty cycle is limiting factor (enormous difference on AMC-wide bore scanner)
  • Water Fat Shift: minimal. Increase to reduce TR
  • TE hoeft niet in phase: niet belangrijk voor vet want signaal is al dispersed met deze TE. TE~32.23, 27 is te kort.
  • Geen slice gap (maar waarom?)
  • Acquired/Reconstructed Matrix size should match
  • Multiband factor * SENSE ~= 6
  • Half scan: no. Unless minimal TR deviates more than 10% from shortest. But: see Gradient mode
  • Dynamic Stabilization: regular (niet enhanced, kost teveel tijd. Kan ook verstoring geven?)
  • Offc/Ang: free rotatable Yes
  • PNS moderate
  • Flip angle --> Ernst angle A typical T1 value for gray matter @ 3T: 1330 ms (Kruger, et al, 2001).
  • Planning: stevig anguleren. Read-out richting omdraaien AP-->PA?
  • Equidistant dynamic sampling

distortion correction

Create two SE-EPIs for distortion correction (better unwarping in regions with dropout)

Data-export

  • enhanced dicom does not work for >16k images
  • export nifti
  • export PAR/REC or XML/REC to store sequence parameters