Siemens Console Parameter Guide
What every setting on the syngo protocol card does, with the physics, the trade-offs, and the practical picks. Focused on MAGNETOM (VE/XA line).
On this page
How to read the consoleContrast cardResolution cardGeometry & SystemFlip-angle modes ★RF pulse types ★HASTE playbook ★Sequence cheat-sheet ★Vendor terms & refsSources- On the Siemens syngo protocol, averages raise SNR and fight motion, while concatenations split slices across multiple TR passes to lift the slice ceiling or drop SAR per pass, at a linear time cost.
- Siemens RF pulse type: Fast uses short, high-amplitude pulses for the shortest echo spacing and TE but higher per-pulse SAR; Low SAR uses longer, lower-amplitude pulses for the lowest SAR but longer echo spacing and time; Normal sits between.
- On the Siemens Sequence card, higher bandwidth (Hz/px) shortens echo spacing and reduces chemical-shift and susceptibility artefact but lowers SNR (proportional to 1/√BW); echo spacing is set by bandwidth together with RF pulse type and matrix.
- Siemens iPAT (GRAPPA) parallel imaging cuts scan time, or the echo-train length in single-shot sequences such as HASTE and EPI, but lowers SNR and adds a risk of reconstruction artefact.
- Interpolation is not resolution: 2× interpolation doubles the displayed matrix without adding true detail, which comes from base and phase resolution and voxel size.
Explain it simply
- On Siemens, averages repeat the scan for a cleaner image and fewer motion problems. Concatenations spread slices over several passes to fit more slices or lower heating per pass, each pass adding time.
- Siemens has three radio-pulse settings. ‘Fast’ uses short, strong pulses: quickest echoes, more heating per pulse. ‘Low SAR’ uses longer, weaker pulses: least heating, but slower. ‘Normal’ sits between.
- Raising bandwidth on Siemens shortens the gap between echoes and reduces fat-shift and distortion near metal or air, but makes images grainier. The radio-pulse setting and image matrix also set that gap.
- Siemens’ speed-up setting (iPAT) shortens the scan, or the echo train in single-shot scans, but makes the image grainier and can add artefacts when the image is rebuilt.
- Upscaling the image (interpolation) makes it look finer but adds no real detail. Real detail comes from the actual sampling settings and the size of each image block.
A guide only: follow your departmental protocols and regional requirements.
How the syngo protocol is organised
Every Siemens protocol opens as a stack of parameter cards (tabs) across the top of the exam card. The settings you touch daily live in five of them.
| Card | Owns | Daily levers |
|---|---|---|
| Routine | The everyday knobs | Slices, TR, TE, averages, concatenations, distance factor |
| Contrast | Signal weighting | TE, TR, flip angle, TI, fat sat, magn. prep, turbo/echo train |
| Resolution | Sampling matrix | Base/phase resolution, phase FoV, PAT/iPAT, partial Fourier, filters |
| Geometry | Where & how thick | FoV, slice thickness, orientation, saturation regions, tilt |
| Sequence (Part 1 & 2) | The engine room | Bandwidth, RF pulse type, flip-angle mode, echo spacing, RF spoiling, asymmetric echo, reordering |
| Physio | Motion/timing | Triggering, gating, dark-blood, navigators |
The three quantities everything trades against
SNR
Grows with voxel volume, √(averages), √(1/bandwidth) and lower acceleration.
SAR / B1+rms
Rises with B0², flip angle², pulses-per-second and shorter TR. The main brake at 3T.
Echo spacing (ESP)
Time between refocusing echoes in TSE/HASTE. Short ESP = less blurring & distortion. Driven by bandwidth and RF pulse duration.
Scan time
TR × phase lines × averages ÷ (turbo factor × acceleration).
Contrast card
| Setting | What it does | Push up → | Push down → |
|---|---|---|---|
| TR | Time between excitations; T1 weighting & slice count | More slices, more T2/PD, more SNR, longer | More T1, fewer slices, faster |
| TE | Echo time; T2/T2* weighting | More T2, less signal | Less T2 (PD/T1), more signal |
| TI | Inversion time; nulls a tissue (STIR/FLAIR/MP-RAGE) | Set to 0.69×T1 to null a tissue at long TR | |
| Flip angle | Excitation (GRE) / refocusing (TSE) angle | More T1 & signal (GRE, to Ernst); more SAR | Less SAR, flatter contrast, less TSE blurring |
| Turbo factor / ETL | Echoes per TR in TSE | Faster, more blurring, longer train | Sharper, truer T2, slower |
| Fat sat | Fat suppression method | SPAIR’s adiabatic inversion tolerates 3T B1 inhomogeneity better than conventional spectral fat-sat (both stay B0-sensitive); Dixon copes well with B0 inhomogeneity, useful for large or off-centre FoV (Del Grande et al. 2014) | |
| Magn. preparation | Dark-blood, T2-prep, MTC, inversion | Adds a prep train before readout (extra SAR & time) | |
Resolution card
| Setting | What it does | Trade-off |
|---|---|---|
| Base resolution | Readout (frequency) matrix | ↑ sharpness, ↓ SNR, cheap in time |
| Phase resolution % | Fraction of phase lines sampled | ↑ sharpness, ↑ time linearly |
| Phase FoV % | Phase FoV as % of read FoV | Shrink to save time; too small → wrap |
| PAT / iPAT (GRAPPA) | Parallel-imaging acceleration | ↓ time (fewer shots in multi-shot TSE; a shorter echo train in single-shot HASTE/EPI), but ↓ SNR by √R×g & recon artifact risk |
| Partial Fourier (phase) | Samples >½ k-space, synthesises rest | ↓ time (and ↓ effective TE in single-shot EPI/HASTE), ↓ SNR & some blurring. HASTE is partial-Fourier (~60%) |
| Asymmetric echo (read) | Partial Fourier in readout | Shortens min TE (short-TE/in-phase GRE) |
| Filters | Normalise, elliptical, distortion-corr | Prescan Normalize evens surface-coil shading; 2D/3D distortion correction fixes gradient-non-linearity geometry (keep it on for measurements, large FoV and radiotherapy planning); elliptical/raw filters change k-space weighting, trading ringing against sharpness |
Geometry & System / Sequence cards
Geometry
| Setting | Notes |
|---|---|
| FoV read / phase | Smaller FoV → higher resolution at fixed matrix, less SNR. Keep anatomy inside to avoid wrap. |
| Slice thickness / gap | Thinner = more resolution, less SNR, more slices/SAR. Distance factor = % of slice thickness. |
| Saturation regions | Pre-sat slabs to kill flow/motion/fat ghosts; each adds SAR & time. |
| Orientation / tilt / phase dir | Swap phase & read to move wrap/ghosts off the anatomy of interest. |
Sequence: Part 1 (bandwidth & echo)
| Setting | Notes |
|---|---|
| Bandwidth (Hz/px) | Higher BW → shorter ESP, less chemical-shift & susceptibility, lower SNR (∝1/√BW). Shortens echo spacing, along with RF pulse type and matrix. |
| Echo spacing | Often read-only (result of bandwidth + RF pulse type + matrix). Minimise for HASTE/EPI/diffusion. |
| Flow comp | Rephases flow: fewer flow ghosts, longer TE/ESP. |
Sequence: Part 2 (the engine room)
| Setting | Notes |
|---|---|
| RF pulse type | Low SAR / Normal / Fast (see dedicated tab). Trades SAR against echo spacing and minimum timing. |
| Flip-angle mode | Constant / T2-var / hyperecho (see dedicated tab). Trades SAR & blurring against pure T2 contrast. |
| RF spoiling | Kills residual transverse coherence in spoiled GRE (FLASH). Leave on for T1 GRE. |
| Reordering / turbo direction | Linear vs centric vs elliptical. Sets which k-space lines land at the effective TE. |
| Optimisation (SAR) | Lets the sequence relax pulses to stay under the SAR limit at a small IQ cost. |
Flip-angle modes ★
In a TSE/HASTE echo train, each echo is refocused by an RF pulse. The flip-angle mode decides whether every refocusing pulse is the same angle, or whether the angle is swept along the train. This one setting governs SAR, through-train signal stability and blurring.
| Mode | Refocusing angles | SAR | Blurring | T2 contrast | Best for |
|---|---|---|---|---|---|
| Constant (180°) | Flat, high (150–180°) | Highest | Rises as the train lengthens | Truest | Thin-slice / high-res, short trains, 1.5T |
| T2-variable (VFA) | Swept, tuned to flatten T2-weighted signal | Low | Lower for long trains | Slightly reduced | Long-train 3D SPACE, routine 2D T2 at 3T; variable refocusing angles can also help single-shot HASTE (see note below). |
| Hyperecho | Symmetric sweep around a central full-angle hyperecho | Low | Not ranked here (depends on the angle schedule) | Reduced | SAR-limited long trains |
Echo-train decay and blurring (the k-space reason)
Signal surviving to each echo depends on the refocusing history. With variable/hyperecho low angles the echo amplitudes evolve differently across the train: variable-flip-angle schedules designed to hold the signal steady (T2-var, SPACE) slow the signal decay, so a long train blurs less than a constant high-angle train of the same length, at some cost in T2 contrast and SNR (Busse et al. 2006; Mugler 2014). Both schemes cut SAR well below constant 180° trains; the exact saving depends on the prescribed angles (Hennig & Scheffler 2001; Hennig et al. 2003). Echo spacing is set mainly by RF pulse type, bandwidth and matrix; check the displayed echo spacing after changing flip-angle mode. A longer echo train (in real time) means k-space lines late in the train are more T2-decayed than early ones. That amplitude taper across k-space acts like a filter, broadening the point-spread function → blurring in the phase-encode direction. So the blurring penalty stacks two things: the shape of the decay across the train, and any increase in echo spacing that stretches that decay out.
Cost of low angles: reduced T2 contrast
Because hyperTSE runs low refocusing angles, it delivers less T2 contrast than a constant-180° train at the same TE. On heavily T2-weighted work where lesion conspicuity is everything, nudge the angle up or fall back to constant.
Long train, SAR-bound, contrast-tolerant → hyperecho / T2-var. Short train, thin-slice, contrast-critical → constant. The flip-angle value is a separate knob layered on top (see the HASTE section).
Variable refocusing flip angles can improve single-shot FSE: in Loening et al. (2015) they stabilised the signal across the train, reduced T2-decay blurring, lowered SAR and increased speed at 3T. Whether Siemens’ T2-var or hyperecho mode suits a given HASTE protocol depends on the design, so compare both on your scanner against the manufacturer’s default protocol and your site protocols. More on the HASTE tab.
RF pulse types ★
The syngo RF pulse type selector (Sequence → Part 2) offers three designs for most sequences. They trade SAR against echo spacing and minimum timing.
| Type | Pulse | ESP / min TE | Slice profile | SAR / B1+rms | Use when… |
|---|---|---|---|---|---|
| Low SAR | Long duration, low B1 amplitude | Longest | Not ranked here: Siemens describes Low SAR pulses as longer, lower-power pulses that may need slightly longer TE and TR; compare slice profile and cross-talk on your own system | Lowest | SAR-limited and can afford slightly longer TE, TR and echo spacing |
| Normal | Balanced default | Between Fast and Low SAR | Not ranked here | Moderate | Everyday choice for routine TSE/GRE |
| Fast | High bandwidth, short duration | Shortest ESP & TE | Not ranked here: Fast pulses are the shortest; compare slice profile and cross-talk on your own system | Highest per pulse | Sequences where short echo spacing makes image quality: HASTE, EPI, TrueFISP, TurboFLASH |
How this interacts with flip-angle mode
- Single-shot, blurring-sensitive (HASTE): priority is minimum echo spacing → favour Fast, and check the displayed echo spacing.
- Thin-slice high-res (MRCP thin-slab, small-part): train is short → Normal (or Low SAR if SAR-bound), with a constant flip angle for the truest T2 contrast; check slice profile and echo spacing on your scanner.
- Long routine TSE / 3D SPACE: SAR dominates → Normal pulse + hyperecho/T2-var flip mode.
Stacking Low SAR pulse + hyperecho mode minimises SAR, but the longer Low SAR pulse lengthens echo spacing. Great for a SAR-crashed sequence, worst for blurring. Don’t reach for both on a sharpness-critical scan.
HASTE playbook ★
HASTE (Half-Fourier Acquisition Single-shot Turbo spin Echo) grabs ~60% of 2D k-space in one very long echo train after a single excitation. Tuning it is a fight against T2 decay across that train.
Because k-space is filled during one long echo train, later lines are acquired at longer effective echo times and are more T2-attenuated, especially short/intermediate-T2 tissue. That amplitude taper across k-space is a low-pass filter → T2 blurring in the phase-encode direction. Half-Fourier worsens it because sampled lines sit further from centre. Minimising echo spacing and stabilising the flip-angle envelope is how you claw sharpness back.
Practical recipe (routine body/abdomen HASTE)
| Setting | Pick | Why |
|---|---|---|
| Flip-angle mode | Hyperecho or T2-var (compare) | Long single-shot train is deeply SAR-bound, esp. at 3T; both schemes cut SAR, so compare them on your scanner |
| Refocusing flip angle | Reduced (well below 180°) | Starting point only: balances T2 contrast, SNR and SAR; values vary by vendor protocol, field strength and body region, so confirm against your scanner’s default HASTE protocol and SAR limits. Lower loses contrast; 180° blows SAR |
| RF pulse type | Fast | Shortest echo spacing → least T2 blurring & distortion, the dominant single-shot failure mode |
| Bandwidth | High | Further shortens ESP and cuts chemical-shift |
| PAT / partial Fourier | On (GRAPPA 2–3) | Shortens effective train → less decay across k-space → less blurring |
T2-var holds the echo envelope flat for one prescribed target T2; hyperecho is symmetric around a central full-angle hyperecho at the k-space centre. Both cut SAR well below constant 180°. In single-shot FSE, variable refocusing flip angles stabilised the signal across the train, reduced T2-decay blurring, lowered SAR and increased speed at 3T (Loening et al. 2015). Which scheme suits a given HASTE protocol depends on the vendor’s implementation, so compare both on your scanner against the manufacturer’s default protocol and your site protocols.
The exception: thin-slice / high-res HASTE (e.g. MRCP thin-slab)
On thin-slice, high-matrix HASTE the pulses and geometry force echo spacing up. Longer echo spacing stretches the T2 decay across an already-long train → more blurring exactly where you need crisp thin-slice detail. Echo spacing is set mainly by RF pulse type, bandwidth and matrix, so keep it tight with a Fast/Normal pulse and check the displayed value after any change; a constant flip angle gives the truest T2 contrast. You pay in SAR; manage it with concatenations, TR, fewer slices per pass or PAT rather than by softening the flip-angle scheme.
So the decision rule is: routine thick-slice HASTE → a reduced refocusing angle (hyperecho or T2-var, compared on your scanner); thin-slice / resolution-critical HASTE (MRCP thin slabs, small-part) → constant flip angle, protect echo spacing.
3T localiser caveat
At 3T the shorter RF wavelength drives B1 inhomogeneity and dielectric (standing-wave) shading across the body, and the long HASTE train is SAR-heavy and contrast-soft. On a fast localiser that shows up as uneven brightness, signal dropout and poor tissue definition, so a HASTE localiser can be degraded at 3T. A fast GRE or TrueFISP-type localiser is a common alternative for planning at 3T (local practice, not a published standard), and use dielectric pads + patient-adaptive B1 shimming when body HASTE itself is needed.
RF pulse type summary for HASTE
HASTE is the textbook home of the Fast RF pulse; measurement speed and short echo spacing are exactly what it needs. Only drop to Normal/Low-SAR if SAR or another constraint forces it, accepting the echo-spacing (blurring) penalty.
Sequence cheat-sheet ★
Starting-point picks for the two levers that matter most, flip-angle mode and RF pulse type, plus the one thing to protect on each sequence. Values are defaults to reason from, not site protocols.
| Sequence | Flip-angle mode | RF pulse | Protect | Notes |
|---|---|---|---|---|
| 2D T2 TSE (routine) | T2-var / hyperecho at 3T; constant OK at 1.5T | Normal | Turbo factor not too high | VFA cuts SAR at 3T; keep ETL modest to limit blurring |
| 2D T1 TSE | Constant (short train) | Normal | Short TE, low ETL | Short echo train → constant angle keeps contrast crisp |
| PD/T2 dual-echo TSE | Constant / T2-var | Normal | Echo spacing | Balance the two effective TEs |
| FLAIR | T2-var / hyperecho | Normal | TI (CSF null), SAR | Long TR/TE/TI is SAR-heavy → VFA helps a lot at 3T |
| STIR | T2-var / hyperecho | Normal | TI (fat null ~0.69×T1fat) | Adiabatic inversion adds SAR; VFA offsets it |
| HASTE (thick-slice) | Hyperecho or T2-var, reduced angle (confirm locally) | Fast | Echo spacing (blurring) | The workhorse setting; short ESP is everything |
| HASTE / thin-slab MRCP | Constant | Fast / Normal | Echo spacing | Long echo spacing blurs thin slices (set by pulse type, bandwidth and matrix); keep angle flat |
| 3D MRCP (SPACE, resp-trig) | T2-var (SPACE VFA) | Normal | SAR, navigator efficiency | Very long 3D train; VFA mandatory for SAR & SNR |
| 3D T2/PD SPACE | T2-var (VFA core of SPACE) | Normal | SAR, blurring | SPACE is a VFA sequence by design |
| 3D T1 MP-RAGE | n/a (GRE readout) | Normal | TI, spoiling | Contrast set by prep inversion, not refocus angles |
| DWI / EPI | n/a (single-shot EPI) | Fast | Echo spacing, distortion | Short ESP + high BW + PAT to cut distortion/blur |
| TrueFISP / bSSFP | n/a (balanced GRE) | Fast | Shim (banding), TR | Fast pulse for short TR; good 3T localiser alternative |
| FLASH / VIBE (T1 GRE) | n/a (spoiled GRE) | Normal | RF spoiling on, Ernst angle | Flip value near Ernst for T1; keep spoiling on |
| TOF MRA | n/a (spoiled GRE) | Normal | Flip for inflow, MTC SAR | Higher flip boosts background suppression at SAR cost |
See the Flip-angle, RF-pulse and HASTE tabs for the reasoning behind each pick.
Vendor terminology (Siemens → others)
| Siemens | GE | Philips | Canon |
|---|---|---|---|
| TSE | FSE | TSE | FSE |
| HASTE | SSFSE | SSH-TSE / Ultra-fast SE | FASE |
| Turbo factor | ETL | Turbo factor | ETL / shot factor |
| SPACE (3D TSE, variable flip angle); hyperecho is a separate Siemens refocusing scheme | CUBE (VFA) | VISTA (VFA) | 3D MVOX |
| iPAT (GRAPPA) | ASSET / ARC | SENSE | SPEEDER |
| TrueFISP | FIESTA | bFFE | True SSFP |
| FLASH (spoiled GRE) | SPGR | T1-FFE | Field Echo |
| TurboFLASH | FastSPGR / FGRE | TFE | Fast FE |
| SPAIR | ASPIR | SPAIR | SPAIR |
Sources
- Hennig J, Weigel M, Scheffler K. Hyperecho / variable flip angle refocusing theory; Development & optimization of Hyperecho-TSE for reduced RF power. ScienceDirect
- Hyperecho-Turbo Spin-Echo Sequences at 3T: Clinical Application in Neuroradiology. AJNR 2008;29(5):956. AJNR · PMC
- Increased speed and image quality in single-shot FSE via variable refocusing flip angles. PMC4684814
- HASTE with parallel acquisition and T2-decay compensation. PMC2630054
- HASTE / SS-FSE physics: blurring, effective TE, half-Fourier. Questions & Answers in MRI · Hyperechoes
- RF pulse types (Low SAR / Normal / Fast) & SAR reduction. How to reduce SAR
- Siemens MRI Acronyms: Cross-Vendor Comparison. Siemens Healthineers PDF
- Ultrafast T2-weighted HASTE at 3T (blurring / DL acceleration). PMC12265358
Parameter behaviour reflects the syngo MR VE/XA interface; exact labels vary by software line and sequence. Recipe values are starting points. Confirm against your site’s protocols and SAR limits.