Adjusting the image brightness on Signa

This procedure will change the image intensities for a single series (multiple scans on the same series will have the same intensity.)

The image intensity is scaled by a CV called 'cfcgain'. Higher numbers represent brighter images. The appropriate scale factor will yield a nominal signal intensity for brain that is comparable to the signal to noise ratio of the scans. Values of 500 or so in the image intensity will be about right. See the Modify CV's HowTo note for details on how to adjust the parameter.

1. Program the sequence and proceed to the the scan setup page
2. Find the CV called, 'cfcgain'
3. Determine the nominal signal intensity in an unmodified image using the ROI tool.
4. Calculate the ratio: R = 500/nominal signal intensity.
5. Multiply the cfcgain by R
6. Touch [Download]
7. Scan

As far as I can tell, further modifications to cfcgain will not be accepted until you quite the current series and start a new one.

1. Get an xterm
2. Once the window open on the Signa console, type:

   cfe

   You will see a crude interactive menu system that reads:

   1. Coil Configuration File
   2. MR Configuration File
   3. SAR Configuration File
   4. ThreeD

   Type ctrl-h for a moderately helpful help screen

3. Select 1
4. Using ctrl-u and ctrl-d move to the line labeled Recon Scale factor
5. Write down the current value. Make sure that you enter this somewhere we can find it (e.g., the scanner status report form)
6. Edit the value. Higher numbers should represent brighter signal
7. Type ctrl-Q twice to exit and save the edited file.
8. When done, you can either touch [Cancel] or type 'exit' to leave the GShell