• Object ID: 00000018WIA302BE870GYZ
  • Topic ID: id_40021902 Version: 1.3
  • Date: Aug 15, 2022 7:05:21 PM

No Slab Wrap

Figure 1. No Slab Wrap selection

No Slab Wrap is a slice oversampling technique for 3D applications that acquires more data to avoid slice wrap.

Figure 2. Full K-space in slice direction and No Slab Wrap
Table 1. Image legend
NumberDescription
1Full K-space in z or slice direction.
2No Slab Wrap with slice oversampling in z or slice direction.
Figure 3. No slab wrap with two different factors
Table 2. Image legend
NumberDescription
LeftTop image is the acquired axial with a No Slab Wrap factor = 1.0. Note the alias artifact. The bottom image is a coronal reformated image. Note the wrap artifact at the bottom of the reformated image.
RightTop image is the acquired axial with a No Slab Wrap factor = 1.3. Note that there is no alias artifact. Bottom images is a coronal reformated image.

The No Slab Wrap scan parameter is only available with the 3D scan mode. It is only compatible with some PSDs, for example:

  • 3D Fast Spin Echo Family applications, which include 3DFSE, 3D FRFSE-XL, CUBE, CUBE T2 Flair, CUBE-DIR etc.
  • 3D Gradient Echo Family applications, which include 3D FGRE, 3D FSPGR, 3D FIESTA, 3D FIESTA-C, 3D GRE, LAVA, 3D MERGE, 3D SPGR, SWAN, VIBRANT, BRAVO, MPRAGE, DISCO, TRICKS, COSMIC, IDEAL IQ, 3D CINE etc.
  • 3D TOF-GRE, 3D TOF-SPGR

Select a No Slab Wrap factor from the menu.

  • Factor range is 1.0 - 4.0. For example, if you prescribed 100 slices with a no slab wrap factor of 1.3, 130 slices are acquired. The center 100 slices are kept in the DICOM database and 15 slices on each side of the slab are discarded. These discarded slices typically contain slab wrap artifacts. ​
  • The larger the factor, the longer the scan time but the less wrap artifact and shading in the slab direction is achieved. To balance the scan time increase when No Slab Wrap Factor is increased, consider increasing the ETL for 3dfse/cube; reducing slice resolution, and/or reducing TR for all 3D scans.​
  • The No slab wrap factor eliminates the slab overlap parameter on the scan parameter screen. The PSD automatically calculates the slab overlap number based on the No Slab Wrap factor and the volume size.