Standard protocols and parameters:

All sites have agreed upon the following minimum standards for structural, resting-state and diffusion tensor imaging.

The sites have consented to limit data acquisition to 3 Tesla MR scanners, using a head coil with 12, preferably 20, 32 or 64 channels.

Parameters for structural imaging

Structural imaging of the entire head with a T1-weighted sequence with a minimal isotropic resolution of 1mm 

Typically 3D-MPRAGE with 176 sagittal slices, TR = 2.25 s, TE = 3.03 ms, TI = 900 ms, FoV = 256 x 256 mm2, flip angle = 9°

Parameters for resting-state imaging

Using a TR = 2 s, TE = 30 ms and the resulting highest number of slices possible (about 34 slices). Slices should be oriented to AC-PC, entailing optimal supratentorial coverage. As many volumes as possible, with a minimum of 250 and a maximum of 3 mm slice thickness.

Moreover, the following procedures are recommended:

Assessing physiological indicators (respiration and heart rate), determining female’s hormonal status (by documenting the number of days between the measurement and the beginning of the latest cycle), and measuring resting-state first, especially before functional paradigms. The participant is provided with standardized instructions that emphasize in particular:

1. No head movement

2. Relax

3. Do not fall asleep

4. Eyes closed or eyes open, respectively

The latter aspect should be documented and kept constant for each site. Depending on the individual research question, either instruction (eyes closed vs. open) will be favored.

Smokers should not experience withdrawal during the measurement.

Parameters for diffusion tensor imaging (DTI)

SE-EPI-sequence with 64 diffusion directions, 50 slices, resolution 2*2*2mm, and a b-value of 1000 s/mm2.

TEs should be minimized in accordance with the gradient system.

Higher b-values will be included, should longer measurement time be available.

Parameters for functional paradigms

Functional images during experimental paradigms as defined by the researches are to be acquired – if deemed appropriate – using the same imaging parameters and brain coverage as during resting-state.

A measurement of the magnetic field homogeneity (field map) is conducted once per participant.

After final agreement on the measurement parameters, the particular configuration for all operating MR scanners is to be deduced, coordinated between sites and documented.


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