Biology Reference
In-Depth Information
used for SWI for a small increase in SNR by reducing the time to
repetition (TR) to the minimum allowed amount with other
parameters being kept the same. This will not typically result in an
increase in imaging time. In our systems, we noted improved image
homogeneity with the 2D sequence so have used this instead.
See Note 5.
After the SWI magnitude images are collected, a special recon-
struction of the phase data must be performed on the imaging
console. These steps for a Bruker imaging system are delineated
below.
1. After the scan completes, clone the reconstruction.
2. Edit the reconstruction by changing the following fi elds:
(a) FT Mode—set all to complex FFT.
(b) PC Mode—set all to fi rst order PC.
(c) Linear PC coeffi cients.
PC0—set all to 0.0.
●
PC1—set all to 180.
●
(d) Output image type—phase Image.
(e) Image signal threshold—0.0.
3. Run the reconstruction.
SWI usually consists of four different images: the magnitude, high-
pass (HP) fi ltered phase, susceptibility weighted (SW), and a mini-
mum intensity projection (mIP). These images are generated from
the two collected images: the magnitude and the phase (Fig.
5
).
1. Transfer the SWI datasets to a workstation running SPIN.
2. Open SPIN and load the SWI magnitude and phase images
(Fig.
5
).
3. If in a different format select “Save Series As…” from “File”
menu and save images in DICOM or Analyze format.
4. Select “MIP/SWI Processing” from the “Process” menu
(Fig.
6
).
5. Adjust the following parameters and run, this generates the
high pass (HP) phase, and SW images. See Notes 6-9.
(a) Filter size: 32-64 (see Note 6).
(b) Phase masking: positive or negative (see Note 7).
(c) Number of phase multiplications: 4 (see Note 8).
(d) Number of slices for each mIP: 1.
6. If mIP images are desired, from the “Process” menu select
“MIP/SWI Processing”, then “Simple MIP” (see Note 9).
7. Select the SW images created in the previous step.
3.2. Processing
for Susceptibility-
Weighted Images
Search WWH ::
Custom Search