Input Images for CEST Analysis
Most of the CEST Analysis requires several images to be acquired with different
frequency offsets relative to the water resonance frequency. These can be
supplied in:
- A single input image containing all frequency offsets and slice locations.
- Multiple input images, with each image containing all slice locations for
one frequency offset. The number of input images will equal the number of
frequency offsets.
- Multiple input images, with each image containing all frequency offsets
for one slice location. The number of input images will equal the number of
slice locations.
Select the appropriate button in the input image configuration.
You also need to set the number of physical slice locations using the spinner:
. This is used as an
additional check that the input configuration is correct.
Also select 
if either:
- You have a single input image with multiple slice locations, and
the different frequency offsets are contiguous (i.e., all frequency
offsets for the first slice are followed by all frequency
offsets for the second slice, etc.)
- You have multiple input images and each of the input images contains all
frequency offsets for one slice location.
The standard masking options apply if you want to mask the input image(s):
- Set an intensity threshold: only pixels with intensity above the
threshold will be processed.
- Apply an image mask: only pixels in the mask image where the intensity
is above zero will be processed.
- Apply an ROI mask: only pixels inside ROIs will be processed.
Inputting the frequency offsets
CEST analysis can be informed about the frequency offsets in one of 3 ways:
You can now select the tab for the type of CEST analysis you want to perform.
.
Enter the frequency offsets (in ppm relative to water) as a comma-separated
list, e.g.:
.
.
Specify the frequency offsets (in ppm relative to water) by entering:
.