3T Multiband: Difference between revisions
From SpinozaWiki
No edit summary |
|||
Line 17: | Line 17: | ||
* Multiband factor * SENSE ~= 6 | * Multiband factor * SENSE ~= 6 | ||
* Half scan: no. Unless minimal TR deviates more than 10% from shortest. But: see Gradient mode | * Half scan: no. Unless minimal TR deviates more than 10% from shortest. But: see Gradient mode | ||
* Dynamic Stabilization: regular (niet enhanced, kost teveel tijd) | * Dynamic Stabilization: regular (niet enhanced, kost teveel tijd. Kan ook verstoring geven?) | ||
* Offc/Ang: free rotatable Yes | * Offc/Ang: free rotatable Yes | ||
* PNS moderate | * PNS moderate |
Revision as of 09:55, 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?
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