MR11 equipment reference¶

This page describes the equipment you use around MR11, the Siemens MAGNETOM Cima.X 3T research scanner at UZ Leuven Gasthuisberg. For the step-by-step session, see the Scanning procedure. For the 7T in Brussels, see Flanders 7T.

For detailed information, go to the radiology wiki

The manuals and photos of each device are on the radiology wiki, under Peripheral Equipment › MR11 - Cima.X 3T (stimulus PC, trigger box and buttons, in-room screen, audio system). This page keeps what you need to program and run an experiment.

Open the radiology wiki (MR11)

You need an account: ask Rodrigo Trevisan Massera (rodrigo.trevisanmassera@kuleuven.be).

The MR11 suite¶

Scanner: Siemens MAGNETOM Cima.X 3T, in use since 11 June 2026 (software XA61, service pack 4 since 25 August 2026).
Head coils: 64-channel (default) and 20-channel head coils.
Location: Beeldvorming 2, Gele straat, Poort 2, niveau 0, MR11 (UZ Leuven Gasthuisberg).
Rooms: the console room (scanner console, stimulus PC, trigger box, audio system and screen control box), the magnet room, the technical room, preparation rooms 1 and 2 (participant instructions and preparation; the XNAT download PC is in preparation room 1), a waiting room and a storage room.

The magnetic field reaches outside the magnet room

The 5 Gauss line extends into the technical room, and the hallway door of the magnet room is only about 2.7 m from the magnet centre. Bring no equipment into the MRI department without approval of the MRI Safety Officer (see First steps).

Stimulus PC¶

The hospital stimulus PC stands in the console room. It is the standard computer for presenting stimuli at MR11.

Login

Login details are in the contact and passwords document in the Hoplab Teams folder and on the radiology wiki (Stimulus PC page). Do not copy them anywhere public.

Password not accepted?

If the password is not accepted, check for a qwerty-azerty keyboard mismatch. Press alt+shift and ensure EN is selected on the login screen.

Software

PsychoPy v2026.1.3 is installed (radiology wiki, August 2026). Pin this version in your experiment (PsychoPy useVersion) or check that your script runs on it during your test session.

Displays

The PC has two displays:

Display 1 = the in-room screen (what the participant sees);
Display 2 = the local monitor in the console room.

The displays can be set to extend or duplicate in Windows settings. In both modes, the participant screen is screen 1. In PsychoPy Builder, set it under Experiment settings › Screen.

House rules

Don't

Do not use the stimulus PC for data transfer, e-mail or web browsing.
Do not install software yourself. Ask Ron Peeters.

Do

At the end of your session, close all software but leave the PC on.
Take your log files with you at the end of the session (see After scanning).

A lab stimulus laptop is planned

The lab plans to buy its own stimulus-presentation laptop, so that we can maintain the software ourselves and test experiments on the same machine before going to the scanner. It is not available yet: until it is, use the hospital stimulus PC. A laptop can be connected to the in-room screen and the trigger box (see Connecting a laptop), but any laptop brought into the MRI department needs prior approval of the MRI Safety Officer.

Trigger box and buttons¶

MR11 uses a Current Designs fibre-optic response system (fORP). The interface box in the console room receives the scanner trigger and the button presses and sends them to the stimulus PC as keyboard presses over USB.

Mode¶

The box has several output modes, selected with the knob. Check the mode at the start of every session by pressing the knob.

Default: mode 002, HID NAR BYGRT. The box acts as a USB keyboard; keys stay pressed until the button is released ("no auto-release"). This mode works best with the stimulus PC and PsychoPy.
If you find the box in another mode, set it back to 002 and leave it in 002 at the end of your session.
If you find the box turned off, then check that the powercable in the back of the box is inserted.

LEDs on the box show each trigger and button press, which helps when you check the set-up.

Key codes (mode 002)¶

Input	Key sent
Scanner trigger (one per volume)	`t`
First button pad: blue, yellow, green, red	`b`, `y`, `g`, `r`
Second button pad	`d`, `n`, `w`, `e` (from a lab experiment; which colour sends which key, and which pad is left or right, to be confirmed)

The radiology wiki gives the trigger as the letter "T" and the buttons as "B for blue, Y for yellow, etc.". Your script receives them as ordinary key presses (PsychoPy and Psychtoolbox report lowercase key names such as t). Check the exact names with your own script during your test session.

Trigger: one pulse per volume

The scanner sends one trigger (t, shown as "T" on the box) at the start of the run, then one per volume. Start your task on the first trigger, and log the triggers with their timestamps so you can check the timing afterwards.

The fibre-optic trigger cable is fragile (only one of the two installed cables works): do not touch or move it.

No triggers or button presses arrive

Look at the LEDs on the interface box: if they light up, the box receives the signal and the problem is on the PC side (wrong window in focus, script not listening to the right keyboard). If they stay dark, the problem is on the scanner or cable side.
Check that the box is in mode 002.
Restart your script, then PsychoPy.
Do not touch the fibre-optic cables. If the trigger still does not arrive, call the MR technician (40526) or contact Ron Peeters.
Last resort: when the trigger cable failed in July 2026, the radiology team advised starting the task by hand: press t on the keyboard at a known moment of the run (e.g., when the console shows the remaining scan time you planned for). Write down for each run when you pressed it. You can estimate the delay afterwards from the time between the end of the task and the end of the scan, and correct your event timings or drop the first volume.

In-room screen¶

The participant sees the stimuli on a Cambridge Research Systems BOLDscreen 32 UHD, an MR-compatible LCD screen at the back of the scanner, viewed through the mirror on the head coil. Its control box is in the console room.

Property	Value
Default input	Stimulus PC
Default setting	L/R flip ON (corrects the mirror image)
Native resolution	3840 × 2160 at 60 Hz; other input resolutions are rescaled by the screen (manufacturer specification)
Resolution used in lab experiments	1920 × 1080, forced from the experiment script
Screen width × height	698.4 × 392.9 mm (active area, BOLDscreen 32 UHD user guide)
Eye-to-screen distance	1850 mm (used in lab experiments; image size checked in the scanner)

Visual angles

Use the width (698.4 mm) and eye-to-screen distance (1850 mm) above to compute visual angles. Lab experiments force 1920 × 1080 from the script, compute the number of pixels per degree from the resolution, width and distance, and size the stimuli from that; the image size measured on the screen in the scanner matched. The panel itself is 4K and rescales other inputs, so always size stimuli from the resolution your script actually uses. To verify your own script, follow Check your visual angles.

End of session: switch the screen off. The last user of the day puts the cover on the screen in the magnet room (the cover lies on its base).

Check your visual angles¶

Do this once in a test session (phantom or pilot) to verify your own script on the screen, with the computer you will use for the study. Steps 1 and 2 check the set-up values above; steps 3 to 5 check your script. Bring a non-metallic measuring tape: never take a metal tape measure into the magnet room.

Screen size. Show a full-screen image with a thin border from your script. Measure the width and height of the image on the screen.
Viewing distance. The participant sees the screen through the mirror on the head coil, so the viewing distance is the path from the eyes to the mirror plus the path from the mirror to the screen. With the table at its scanning position (no one on it), measure from the mirror to the screen along the line of sight. Then measure from the eyes to the mirror on a screened colleague lying in the coil, before the table moves in, and add the two.
Resolution. Log the resolution your script actually gets, not only the one it asks for (Psychtoolbox and PsychoPy both report the size of the window in pixels).
Convert sizes. A stimulus of θ degrees, centred on the screen, is 2 × viewing distance × tan(θ ÷ 2) wide on the screen; divide by the pixel size (screen width ÷ horizontal resolution) to get pixels. Use this exact formula, or the calculator below, for every size. Multiplying by a fixed number of pixels per degree is only close for small stimuli near the centre of the screen. Scale the whole stimulus with one size and never stretch it: for a non-square image, convert one side and derive the other from the image's aspect ratio in pixels.
Cross-check on the screen. Show a test stimulus that your script sizes at a known visual angle (for example a 10° square). Measure it on the screen and compute its angle as 2 × arctan(size ÷ (2 × viewing distance)). It should match the intended angle. If it does not, go back over steps 1 to 4.
Write it down. Note the measured width, height, distance and resolution, with the date, in your lab notes and in the methods of your paper.

The lab's fMRI task template does step 4 with degToPix (sizes) and eccToPix (positions away from the centre).

Use the calculator to convert between degrees, millimetres and pixels. It is filled in with the values above; change any field for your own set-up.

Turn on JavaScript to use the visual angle calculator.

If you use PsychoPy, enter the measured width, distance and resolution in its monitor settings. Its deg units give every degree the same number of pixels, the approximation of step 4, so stimuli of more than a few degrees come out slightly smaller, and positions slightly closer to the centre, than the exact formula gives. The gap grows with size and with distance from the centre.

Connecting a laptop¶

You may present stimuli from a laptop instead of the stimulus PC, after approval of the MRI Safety Officer (Ron Peeters). Steps used by lab members so far:

Connect the HDMI cable provided at the screen's control box to the laptop, and select input HDMI-2 on the control box (press the input button).
Unplug the trigger box USB cable from the front of the stimulus PC tower and plug it into the laptop. The laptop then receives both the scanner trigger and the button presses as key presses.
At the end of the session, plug the USB cable back into the stimulus PC and switch the screen input back to the stimulus PC.

Display set-up

Use one screen where possible: the in-room screen only, with the laptop's own screen off. Otherwise, use Duplicate in Windows, with both screens at 1920 × 1080, 60 Hz. Before scanning, make sure the Psychtoolbox synchronisation tests or the PsychoPy frame-timing checks run without errors: sync errors usually mean the timing is off, often because more than one screen is in use. Some users have run their task with an extended desktop, but they reported sync errors.

Audio system¶

There are two headphone options:

Siemens headphones (large headset). You talk to the participant through the white Siemens intercom, which plays in the room and in this headset. To also play sound from the stimulus PC, plug in the small audio cable.
Dedicated research headphone system: the blue box under the stimulus PC, with its own blue microphone. It uses smaller ear shells that fit inside the 64-channel head coil (the Siemens headset is too large for most participants in that coil). Use this system with the 64-channel coil.

To play sound (stimuli or music) through the dedicated system:

Start the sound on the stimulus PC.
Turn on the sound system (on/off button at the top left of the back, labelled A).
Press the round volume knob (B) and choose:
- fMRI-VOL to set the volume for the participant;
- fMRI-MONVOL to set the monitoring volume in the console room.
Switch the audio system off at the end of the session.

Participants always wear earplugs as well. Participants who refuse hearing protection cannot be scanned.

The participant cannot hear the sound or you

Check that the audio system is switched on (button A at the back) and that fMRI-VOL is not set too low.
With the Siemens headset, check that the small audio cable is plugged in, otherwise only the intercom is heard.
For the intercom, press the button to talk and release it to listen, with the volume at maximum.
If it still does not work, call the MR technician (40526).

Scanner table and coils¶

Cover the cushions with paper towels. Do not put cushions or equipment on the floor; put them on a shelf.
The 64-channel coil sits on the table about 10 cm from the edge, plugged in at the top of the table. The bottom part must be slotted into the table.
The panic button ("communication button" when you explain it to participants) is plugged in at the bottom left of the table.
After clinical use, the table may be set up differently: check the set-up before your participant arrives.

Eye tracker¶

An EyeLink eye tracker (EyeLink 1000 long range) is planned to be installed at MR11, but is not available yet. If your study needs eye tracking, contact Ron Peeters to confirm whether and when it can be used.