Beauchamp:HowToScan

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Brain picture
Beauchamp Lab



How to Scan

next step is Getting raw data from the scanner

About the BCM CAMRI Siemens Scanners

The BCM CAMRI has 3 whole-body 3T Siemens Magnetom Trios. We usually scan on 3T-5 with the 32-channel head coil. David Ress' former student Andrew Florens examined the acquisition time stamps and found that axial slices are collected from Superior to Inferior (head to foot). If an odd number of slices is acquired, the slice order is

 1, 3, 5, 7, etc.
 2, 4, 6, 8 etc.

If an even number of slices is acquired, the slice order is reversed:

 2, 4, 6, 8, etc.
 1, 3, 5, 7, etc.

See Krista to have your badge activated.

More details on the BCM scanners

  1. Stimuli on the 3T-5 are displayed on an LCD screen. Link to manual here: Cambridge Research Systems BOLD Screen User Guide

The BOLDScreen has a built-in color profile that can make images appear too dark. Instead, use the default color profile as follows:

  1. On the Mac laptop stimulus computer, Click on the Apple, Open "System Preferences"
  2. click on "Displays", select the "Color" Tab
  3. Select the "Color LCD" profile for the second display (the BOLDscreen)

Responses are recorded with a fORP system. Link to Jung Hwan's user guide here: fORP Configuration For Beauchamp Lab experiments, do the following:

  1. Push in fORP front button
  2. Go to changes modes, select YES
  3. Select Autoconfigure
  4. Scroll down to HID NAR BYGRT, Select
  5. Confirm that Mode is 002 in top right of display

This gives a trigger as a T rather than a 5. An extra step needs to be taken to make sure that the right USB device is selected in Matlab (from the three possibilities).

To access pulse sequences, Click on Ctrl-Esc and select the "Advanced User" program. Type in the password (meduser1). Then go back, and open a Windows Explorer window. The pulse sequences are located under

 C:/medcom/mricustomer/seq

The diffusion vectors are stored in the file

 DiffusionVectors.txt

If the real-time is not working, make sure you are using the correct pulse sequence (VB17rt EPI). Also check the tabs computer (MacPro):

  1. Change user to admin_local
 $ su admin_local
  1. Kill afni:
 $ kill -9 'cat /Uses/tabs/tabs/var/afni.pid'
  1. If that does not help reboot tabs
  2. You can check the log on the scanner for hints:
 Type logviewer from the command prompt.

Image information in Trios: 76.5 cm from screen to eyeball height of screen is 13.7 in = 34. 8 cm

width of screen is 34.8 * (1024/768) = 46.4 cm atan(23.2/76.5) = 0.29 rad = 16.6 degrees ~30 degrees full width


More stuff on real-time:

  1. Register subject, open Patient Database
  2. Find subject, click on MP-RAGE first, "Send to TABS"
  3. Once AFNI is up, then run rt fMRI sequence (look on "Special card" )