{ "id": "epk4akkt9r", "slug": "steady-state-free-precession-imaging", "title": "Steady-state free precession imaging", "updated": "2026-10-15", "topic_path": [ { "id": "life", "label": "Life and health", "api_url": "https://www.edgepedia.org/api/v1/topics/life" }, { "id": "life.health", "label": "Human health and medicine", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health" }, { "id": "life.health.clinical", "label": "Clinical assessment and procedures", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health.clinical" }, { "id": "life.health.clinical.clinical-imaging", "label": "Medical imaging and radiography", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health.clinical.clinical-imaging" }, { "id": "life.health.clinical.clinical-imaging.magnetic-resonance-imaging-techniques", "label": "Magnetic resonance imaging techniques", "api_url": "https://www.edgepedia.org/api/v1/topics/life.health.clinical.clinical-imaging.magnetic-resonance-imaging-techniques" } ], "geo": [ { "id": "geo.nongeo.t1946.life.health.clinical.clinical-imaging.magnetic-resonance-imaging-techniques", "label": "Non-geographic · 1946 to 2000: Magnetic resonance imaging techniques", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health.clinical.clinical-imaging.magnetic-resonance-imaging-techniques", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1946", "label": "Non-geographic · 1946 to 2000", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946" }, { "id": "geo.nongeo.t1946.life", "label": "Life and health", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life" }, { "id": "geo.nongeo.t1946.life.health", "label": "Human health and medicine", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health" }, { "id": "geo.nongeo.t1946.life.health.clinical", "label": "Clinical assessment and procedures", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health.clinical" }, { "id": "geo.nongeo.t1946.life.health.clinical.clinical-imaging", "label": "Medical imaging and radiography", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health.clinical.clinical-imaging" }, { "id": "geo.nongeo.t1946.life.health.clinical.clinical-imaging.magnetic-resonance-imaging-techniques", "label": "Magnetic resonance imaging techniques", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.life.health.clinical.clinical-imaging.magnetic-resonance-imaging-techniques" } ] } ], "excerpt": "Steady-state free precession (SSFP) is an MRI pulse sequence that uses rapid repeated radiofrequency pulses to maintain steady transverse magnetization, producing high-signal images with bright-fluid contrast.", "snippet": "Steady-state free precession (SSFP) is an MRI pulse sequence that uses rapid repeated radiofrequency pulses to maintain steady transverse magnetization, producing high-signal images with bright-fluid contrast.", "node": "life.health.clinical.clinical-imaging.magnetic-resonance-imaging-techniques", "markdown": "# Steady-state free precession imaging\n\nSteady-state free precession (SSFP) is a magnetic resonance imaging pulse sequence that uses rapid repeated radiofrequency pulses to maintain steady transverse magnetization, producing high-signal images with bright-fluid contrast. Its balanced form (bSSFP) is the method of choice for cine imaging (rapid MRI frames showing moving heart as movie) at 1.5 T because it provides high signal-to-noise ratio (SNR) and excellent contrast between myocardium and blood pool.[1](https://link.springer.com/article/10.1186/s12968-020-00607-1)\n\n| Key fact | Value | Source |\n|---|---|---|\n| Signal dependence for TR ≪ T1, T2 | Approximately proportional to a T2/T1 expression (Freeman–Hill), independent of TR and TE | [2](https://onlinelibrary.wiley.com/doi/10.1002/mrm.22053) |\n| Typical TR and flip angle | TR 3–6 ms; flip angle 50–80° (70–90° when \\( T_{1} \\approx T_{2} \\)) | [3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf) |\n| Gradient design | Balanced gradients cancel dephasing equally in each of the three spatial directions | [4](https://pc.kjronline.org/pdf/10.3348/kjr.2015.16.3.550) |\n| Cardiac cine CNR vs FLASH | 2.0× higher (4.0× normalized for time and pixel size) | [5](https://s.mriquestions.com/uploads/3/4/5/7/34572113/carr_et_al_segmented_truefispradiology2e2192e32er01jn44828.pdf) |\n| Banding periodicity | Signal nulls every 1/TR in resonance frequency; dark bands where phase per TR reaches \\( \\pi \\) | [6](https://usc-mrel.github.io/Journal/2007/Nayak_2007_MRM.pdf), [5](https://s.mriquestions.com/uploads/3/4/5/7/34572113/carr_et_al_segmented_truefispradiology2e2192e32er01jn44828.pdf) |\n| Maximum signal | Up to ~50% of M0 when T1 ≈ T2 (CSF, fat); 10–30% of M0 when T2/T1 ≪ 1 | [3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf), [7](https://onlinelibrary.wiley.com/doi/10.1002/jmri.24163) |\n| Field-strength behavior | Default cine method at 1.5 T; off-resonance sensitivity worsens banding at 3 T | [1](https://link.springer.com/article/10.1186/s12968-020-00607-1) |\n\n## How it works\n\nAn SSFP signal is generated by a train of RF pulses with a constant flip angle α (not 0° or ±180°), a constant repetition time \\( \\mathrm{TR} > 0 \\), and a defined degree of phase coherence or phase cycling.[8](https://onlinelibrary.wiley.com/doi/10.1002/mrm.10410) Under constant flip angle, phase, and TR, a steady state of the magnetization is established after several TR periods, on the order of \\( 5 \\cdot T_{1}/\\mathrm{TR} \\).[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf) Coherent SSFP sequences maintain transverse coherence between RF pulses in this steady-state regime, whereas spoiled gradient-echo sequences deliberately destroy transverse coherence and, even at short TR, at most reach a longitudinal steady state.[7](https://onlinelibrary.wiley.com/doi/10.1002/jmri.24163)\n\nBalanced gradients are the defining mechanism of bSSFP: within each TR, every applied gradient pulse is compensated by one of opposite polarity, so gradient-induced dephasing is exactly zero, and the gradients cancel equally in each of the three spatial directions[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf), [4](https://pc.kjronline.org/pdf/10.3348/kjr.2015.16.3.550) On resonance, the resulting signal is a function of T1, T2, TR, and flip angle α; for TR ≪ T1, T2 it reduces, via the Freeman–Hill formula, to a T2/T1-type proportionality independent of TR and echo time[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf), [2](https://onlinelibrary.wiley.com/doi/10.1002/mrm.22053) This \\( T_{2}/T_{1} \\) weighting gives very high signal for fat and water, and the sequence is less sensitive to conventional \\( T_{2}^{*} \\) effects than other gradient-echo sequences.[9](https://pubs.rsna.org/doi/10.1148/rg.284075031) The angle between the magnetization and the RF pulse depends on precession induced by static-field off-resonance during TR, which is kept very short (\\( \\mathrm{TR} = 2\\text{–}20 \\) ms).[10](https://pmc.ncbi.nlm.nih.gov/articles/PMC3398389/)\n\n## How it is done\n\nA bSSFP acquisition uses a rapid, consecutive train of excitation pulses at TR of roughly 3–6 ms with fully balanced gradients[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf), [4](https://pc.kjronline.org/pdf/10.3348/kjr.2015.16.3.550) Flip angles of 50–80° generate the highest signal; when \\( T_{1} \\) and \\( T_{2} \\) are similar, as in CSF or fat, the optimum is 70–90° and maximum signal approaches 50% of \\( M_{0} \\).[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf) High-performance gradient systems allow TRs as low as 2–4 ms while retaining high SNR.[11](https://onlinelibrary.wiley.com/doi/10.1002/mrm.10542)\n\nStable signals require the total phase, \\( \\phi_{\\mathrm{tot}} = \\phi_{\\mathrm{cyc}} + 2 \\pi \\Delta f \\cdot \\mathrm{TR} \\), to be close to 180°; clinical scanners set the phase-cycling angle \\( \\phi_{\\mathrm{cyc}} \\) at 180° and keep field evolution near zero with short TR and good shimming (adjusting magnetic field uniformity to reduce artifacts).[12](https://synapse.koreamed.org/articles/1027125) For cine, the standardized cardiac protocol uses breath-hold acquisition, 6–8 mm slices, and temporal resolution of ≤45 ms between phases, with parallel imaging or compressed sensing to shorten scan time; banding is managed by shimming, reducing TR, and adjusting the RF frequency with a frequency scout.[1](https://link.springer.com/article/10.1186/s12968-020-00607-1) In angiography, fat saturation is mandatory because bSSFP fat signal exceeds that of inflowing blood.[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf)\n\n## Origin\n\nThe steady-state concept traces to mid-20th-century NMR, where it was shown that under continuous excitation a spin ensemble reaches a dynamic \"free precession\" steady state; practical imaging with these steady-state effects had to wait for faster hardware.[13](https://www.sciencedirect.com/science/article/pii/S0720048X25003377) The alternating repetition time (ATR) bSSFP variant was introduced by J. Leupold, J. Hennig, and K. Scheffler in 2006 in Magnetic Resonance in Medicine.[14](https://doi.org/10.1002/mrm.20790)\n\n## Variants\n\nThe SSFP family is classified into spoiled gradient echo (SPGR, T1-FFE), the gradient-dephased nonbalanced SSFP-FID (FISP, GRASS, FFE), its time-reversed gradient-spoiled version SSFP-Echo (PSIF, T2-FFE), and balanced SSFP (TrueFISP, FIESTA, balanced FFE).[7](https://onlinelibrary.wiley.com/doi/10.1002/jmri.24163) CISS (constructive interference in steady state) is a slow bSSFP variant with TR of approximately 15–20 ms that combines two 3D bSSFP runs with shifted banding artifacts to give banding-free images.[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf) ATR bSSFP applies two alternating repetition times TR1 and TR2, with TR2 one third of TR1 and a 90° RF phase increment, modifying the frequency response to separate or suppress resonances such as fat at a total scan-time cost of about 30%.[14](https://doi.org/10.1002/mrm.20790) A wideband SSFP approach using two alternating repetition times with alternating RF phase establishes band spacing up to two times wider than conventional SSFP with a modest scan-time increase, and has been applied to cine ventricular function and high-resolution cartilage imaging at 3 T.[6](https://usc-mrel.github.io/Journal/2007/Nayak_2007_MRM.pdf)\n\n## Applications\n\nCardiac cine is the dominant use: bSSFP's much higher muscle–blood contrast than FLASH benefits ejection-fraction and ventricular-mass quantification and subsequent segmentation.[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf) Its T2/T1 contrast generates a bright fat signal (\\( T_{2}/T_{1} \\approx 0.3 \\)) comparable to fluids, so fat separation is essential for coronary artery and cartilage imaging.[14](https://doi.org/10.1002/mrm.20790) In fMRI, bSSFP is the fastest non-EPI method but still slower than EPI, limiting spatial coverage; acceleration with parallel imaging and compressed sensing has been demonstrated.[12](https://synapse.koreamed.org/articles/1027125)\n\n## Limitations and alternatives\n\nFor a resonance offset Δν in hertz, the phase accumulated during TR is \\( \\phi = 2 \\pi \\Delta \\nu \\cdot \\mathrm{TR} \\); when \\( \\phi = \\pi \\), signal cancellation produces dark stripes.[5](https://s.mriquestions.com/uploads/3/4/5/7/34572113/carr_et_al_segmented_truefispradiology2e2192e32er01jn44828.pdf) Conventional SSFP has a usable bandwidth of less than \\( 1/\\mathrm{TR} \\), with signal nulls every \\( 1/\\mathrm{TR} \\) in resonance frequency.[6](https://usc-mrel.github.io/Journal/2007/Nayak_2007_MRM.pdf) Bands arise at air–tissue interfaces caused by field inhomogeneities; alternating the RF pulse phase between TR periods shifts the band locations, and acquiring and combining complementary phase-cycled datasets can reduce signal voids at the cost of additional acquisition time, while keeping TR low and proper shimming also help.[9](https://pubs.rsna.org/doi/10.1148/rg.284075031) Shorter TR generally helps reduce off-resonance banding, but the usable TR depends on field strength, shimming, anatomy, and scanner capabilities rather than any universal cutoff.[5](https://s.mriquestions.com/uploads/3/4/5/7/34572113/carr_et_al_segmented_truefispradiology2e2192e32er01jn44828.pdf) Combining datasets acquired at multiple phase-cycling angles fills in each other's signal voids, but multiple-acquisition phase cycling requires multiple steady states, increases scan time by at least a factor of two, and can shift off-resonance into flow regions, inducing new flow artifacts[6](https://usc-mrel.github.io/Journal/2007/Nayak_2007_MRM.pdf), [15](https://link.springer.com/article/10.1186/s12968-023-00988-z)\n\nThe main drawbacks are off-resonance banding and RF heating. At 3 T, increased off-resonance sensitivity worsens dark banding and flow artifacts, requiring careful shimming and occasionally patient-specific frequency adjustment; spoiled gradient echo is the fallback.[1](https://link.springer.com/article/10.1186/s12968-020-00607-1) Because bSSFP needs flip angles of 50–80°, SAR limits can be exceeded beyond 1.5 T; optimized slice-excitation pulses or variable flip angles reduce SAR, and a free-breathing variable-flip-angle cine at 3 T achieved 25% lower SAR than breath-hold constant-flip-angle imaging with similar blood–myocardium contrast but lower qualitative image scores[3](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf), [16](https://pmc.ncbi.nlm.nih.gov/articles/PMC4848168/) Changing the imaging slice produces a transient signal artifact lasting about 150–210 ms; in triggered LV function studies the trigger delay is set so the transient falls in the least critical part of the cardiac cycle.[17](https://onlinelibrary.wiley.com/doi/10.1002/mrm.20489) [Dark flow](https://www.edgepedia.org/dark-flow) artifacts occur in SSFP cine cardiac MR, which is also known as FIESTA, true FISP, balanced FFE, and FRGRE.[18](https://pubs.rsna.org/doi/10.1148/radiol.2302021257) Off-resonance-dependent slice-profile effects can produce out-of-slice signal when the fat peak lies near a band's off-resonance frequency, relevant with contrast agents and the associated susceptibility increase in angiography.[19](https://onlinelibrary.wiley.com/doi/10.1002/mrm.21557)\n\nCompared with spoiled GRE (FLASH), bSSFP gives superior SNR efficiency and stronger T2/T1 contrast, with optimal signal of 10–30% of M0 when T2/T1 ≪ 1, still higher than FLASH[6](https://usc-mrel.github.io/Journal/2007/Nayak_2007_MRM.pdf), [7](https://onlinelibrary.wiley.com/doi/10.1002/jmri.24163)\n\n## References\n\n1. [Standardized cardiovascular magnetic resonance imaging (CMR) protocols: 2020 update](https://link.springer.com/article/10.1186/s12968-020-00607-1)\n2. [Assessment of magnetization transfer effects in myocardial tissue using bSSFP cine MRI](https://onlinelibrary.wiley.com/doi/10.1002/mrm.22053)\n3. [Principles and applications of balanced SSFP techniques (Scheffler & Lehnhardt, Eur J Radiol)](https://www.mriquestions.com/uploads/3/4/5/7/34572113/scheffler_ssfp.pdf)\n4. [Korean J Radiol review of balanced SSFP](https://pc.kjronline.org/pdf/10.3348/kjr.2015.16.3.550)\n5. [Segmented trueFISP cardiac cine imaging (Carr et al., Radiology)](https://s.mriquestions.com/uploads/3/4/5/7/34572113/carr_et_al_segmented_truefispradiology2e2192e32er01jn44828.pdf)\n6. [Wideband SSFP: Alternating repetition time balanced steady state free precession with increased band spacing](https://usc-mrel.github.io/Journal/2007/Nayak_2007_MRM.pdf)\n7. [Fundamentals of balanced steady state free precession MRI](https://onlinelibrary.wiley.com/doi/10.1002/jmri.24163)\n8. [An analytical solution for the SSFP signal in MRI](https://onlinelibrary.wiley.com/doi/10.1002/mrm.10410)\n9. [Steady-State MR Imaging Sequences: Physics, Classification, and Clinical Applications](https://pubs.rsna.org/doi/10.1148/rg.284075031)\n10. [FMRI using balanced steady-state free precession (SSFP)](https://pmc.ncbi.nlm.nih.gov/articles/PMC3398389/)\n11. [Steady-state sequence synthesis and its application to efficient fat-suppressed imaging](https://onlinelibrary.wiley.com/doi/10.1002/mrm.10542)\n12. [bSSFP review (KoreaMed Synapse)](https://synapse.koreamed.org/articles/1027125)\n13. [Balanced steady-state free precession MRI: History and evolution](https://www.sciencedirect.com/science/article/pii/S0720048X25003377)\n14. [J. Leupold, J. Hennig, K. Scheffler (2006). Alternating repetition time balanced steady state free precession. Magnetic Resonance in Medicine.](https://doi.org/10.1002/mrm.20790)\n15. [A dual-stage partially interpretable neural network for joint suppression of bSSFP banding and flow artifacts in non-phase-cycled cine imaging](https://link.springer.com/article/10.1186/s12968-023-00988-z)\n16. [Free-Breathing Variable Flip Angle Balanced SSFP Cardiac Cine Imaging with Reduced SAR at 3T](https://pmc.ncbi.nlm.nih.gov/articles/PMC4848168/)\n17. [Spiral balanced steady-state free precession cardiac imaging](https://onlinelibrary.wiley.com/doi/10.1002/mrm.20489)\n18. [Dark Flow Artifacts with Steady-State Free Precession Cine MR Technique: Causes and Implications for Cardiac MR Imaging](https://pubs.rsna.org/doi/10.1148/radiol.2302021257)\n19. [Off-resonance-dependent slice profile effects in balanced steady-state free precession imaging](https://onlinelibrary.wiley.com/doi/10.1002/mrm.21557)\n\n---\n*Topic: Encyclopedia › Life and health › Human health and medicine › Clinical assessment and procedures › Medical imaging and radiography › Magnetic resonance imaging techniques*\n\n*Initially written Sep 29, 2026 · Edited: Oct 15, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/steady-state-free-precession-imaging", "markdown_url": "https://www.edgepedia.org/steady-state-free-precession-imaging.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Steady-state free precession imaging\", Edgepedia (EdgeChat), https://www.edgepedia.org/steady-state-free-precession-imaging. Edgepedia Community License 1.0.", "credit_md": "\"[Steady-state free precession imaging](https://www.edgepedia.org/steady-state-free-precession-imaging)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/steady-state-free-precession-imaging](https://www.edgepedia.org/steady-state-free-precession-imaging). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Steady-state free precession imaging\", Edgepedia (EdgeChat), https://www.edgepedia.org/steady-state-free-precession-imaging. Edgepedia Community License 1.0.", "speakable": "Steady-state free precession is an MRI pulse sequence that uses rapid repeated radiofrequency pulses to maintain steady transverse magnetization, producing high-signal images with bright-fluid contrast." }