Table 1.
Overview of the used magnetic resonance sequences constituting the test battery for quality assurance testing
| Sequence no. | Name | TR, ms | TE, ms | FA | Bandwidth, Hz/Px | Voxel Size, mm3 | No. Slices | Slice Orientation | Scan Time, min:s | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | RF field | 300 | 17 | 720° | 130 | 1.2×1.2×5 | 1 | Sagittal* | 1:19 | Spin echo |
| 2 | Signal-to-noise ratio | 1,000 | 3.6 | 15° | 260 | 1×1×5 | 12 | Sagittal* | 4:16 | Gradient echo |
| 2.5-mm Gap between slices | ||||||||||
| 3 | RF noise spikes | 24 | 1 | NA | 130 | 2×2×10 | 1 | Sagittal* | 0:06 | |
| 4 | RF noise† | 1,400 | 1 | NA | 39 | 0.4×0.4×1 | 50 | Transverse | 5:58 | |
| 5 | Weisskoff (1996) EPI | 2,000 | 30 | 90° | 2,112 | 3.5×3.5×3.5 | 25 | Transverse | 10:44 | Temporal stability estimation |
| 6 | Field map | 704 | 5.11 7.57 | 60° | 260 | 3.5×3.5×3.5 | 21 | Transverse | 1:33 | B0 inhomogeneity estimation Magnitude and phase images |
| 7 | EPI with reference amplitude set to “0 V” | 2,250 | 30 | 78° | 2,112 | 3.5×3.5×3.5 | 21 | Transverse | 1:53 | 50% Phase oversampling‡ 750-ms Gap between consecutive volumes |
| 8 | “Paradigm” EPI§ | 2,250 | 30 | 78° | 2,112 | 3.5×3.5×3.5 | 21 | Transverse | 1:53 | 50% Phase oversampling‡ 750-ms Gap |
| TMS pulses were applied in TMS+EEG setupa Reference amplitude: 104.4 V | ||||||||||
| 9 | MPRAGE | 2,250 | 2.6 | 9° | 200 | 1×1×1 | 192 | Sagittal | 8:26 | T1-weighted anatomic image |
Sagittal slice in line with main horizontal axis at center of transcranial magnetic stimulation (TMS) coil.
Radio frequency (RF) noise check in which the receiver chain of the system was set to a high receiver gain and symmetrically stepped through a bandwidth up to 250 kHz relative to the Larmor frequency of the system (i.e., 127.7 MHz) in steps of 10 kHz (i.e., 50 steps in total covering a range of 500 kHz).
50% Phase oversampling to reduce ghost artifacts of TMS coil (Bestmann et al. 2008a). §This echo-planar imaging (EPI) is similar to that used in the resting-state human data collection except that in the latter more volumes were collected and intensity was set to 80% of the stimulator output.
In TMS-EEG setup, each 9–27 s (average of 18 s), a TMS pulse (at 100% maximum stimulator output) was delivered in-between acquisitions. TR, repetition time; TE, echo time; FA, flip angle; NA, not applicable; B0, static magnetic field.