Are TrueFISP images T2/T1‐weighted?

Huang, Teng Yi; Huang, Ing Jye; Chen, Cheng-Yu; Scheffler, Klaus; Chung, Hsiao Wen; Cheng, Hui

doi:10.1002/mrm.10260

Cited by 50 publications

(53 citation statements)

References 16 publications

(21 reference statements)

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“…Centrically encoded SSFP imaging offers the possibility of acquiring SSFP images during the transient phase prior to SSFP steady-state formation (increased T 2 contrast in otherwise predominantly T 2 /T 1 weighted images) or enhancing contrast modification by preceding preparation pulses (e.g., inversion recovery, fat saturation) (15). However, large gradient amplitude differences for successive phase encode lines result in eddy current induced artifacts and cause a smearing of the image in the phase encoding direction.…”

mentioning

confidence: 99%

Double average parallel steady‐state free precession imaging: Optimized eddy current and transient oscillation compensation

Markl

Leupold

Bieri

et al. 2005

Magnetic Resonance in Med

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Balanced steady-state free precession (SSFP) imaging is sensitive to off-resonance effects, which can lead to considerable artifacts during a transient phase following magnetization preparation or steady-state interruption. In addition, nonlinear kspace encoding is required if contrast-relevant k-space regions need to be acquired at specific delays following magnetization preparation or for transient artifact reduction in cardiac-gated k-space segmented CINE imaging. Such trajectories are problematic for balanced SSFP imaging due to nonconstant eddy current effects and resulting disruption of the steady state.In this work, a novel acquisition strategy for balanced SSFP imaging is presented that utilizes scan time reduction by parallel imaging for optimized "double average" eddy current compensation and artifact reduction during the transient phase following steady-state storage and magnetization preparation. Double average parallel SSFP imaging was applied to k-space segmented CINE SSFP tagging as well as nongated centrically encoded SSFP imaging. Phantom and human studies exhibit substantial reduction in steady-state storage and eddy current artifacts while maintaining spatial resolution, signal-to-noise ratio, and similar total scan time of a standard SSFP acquisition. The proposed technique can easily be extended to other acquisition schemes that would benefit from nonlinear reordering schemes and/or rely on interruption of the balanced SSFP steady state. Magn Reson Med 54:965-974, 2005.

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mentioning

confidence: 99%

Double average parallel steady‐state free precession imaging: Optimized eddy current and transient oscillation compensation

Markl

Leupold

Bieri

et al. 2005

Magnetic Resonance in Med

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“…The MR signal of bFFE can be expressed as signal = M 0 . sin α/[1 + cos α + (1 -cos α)(T1/T2)], where M 0 is the magnetization at thermal equilibrium and α is the flip angle, [4] and the signal of SSh-TSE can be estimated as signal = M 0 . exp(-TE/T2).…”

Section: Discussionmentioning

confidence: 99%

Fetal magnetic resonance imaging of normal spinal cord: Evaluating cord visualization and conus medullaris position by T2-weigted sequences

et al. 2014

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Background: Prenatal magnetic resonance (MR) imaging demonstration of the normal spinal cord and the conus medullaris location has not been well studied. We compared balanced fast field echo (bFFE) with single-shot turbo spin-echo (SSh-TSE) MR sequences for visualizing the normal spinal cord and position of conus medullaris in fetuses. Methods:This retrospective study was approved by the Institutional Review Board of Chang Gung Medical Foundation. We reviewed the MR images of 141 fetuses aged between 16 and 39 gestational weeks, to determine the position of the conus and visualize the spinal cord by using a signal intensity ratio of cerebral spinal fluid (CSF) to the spinal cord. Results:Of the 75 subjects having normal spinal cord and being examined by both bFFE and SSh-TSE studies, the signal intensity ratio of CSF/cord was greater on bFFE images (2.18 ± 0.53) than that on SSh-TSE images (1.21 ± 0.13) (p < 0.05). The conus level identified in the 50 subjects, in whom the lumbosacral spine was appropriately imaged, was located from L1 to L5 levels. The ascendance of the conus correlated moderately with gestational age. Conclusions: With greater signal contrast ratio of CSF to spinal cord, bFFE sequence, when compared with SSh-TSE sequence, provides better visualization of normal spinal cord. The fetal conus medullaris ascends from L5 to L1 levels as the gestational age increases. (Biomed J 2014;37:232-236)

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“…The halfangle-half-TR preparation scheme was used before RF excitation, along with a linear phase-encoding order (16). Note that at the matrix size chosen in this study, the image contrast can be regarded as being largely dominated by the steady-state signal response (12). The body coil was used for signal receiving.…”

Section: Image Acquisitionmentioning

confidence: 99%

“…For 2D imaging, the use of a single fat-suppression RF pulse followed by a centric-ordered SSFP readout should serve the same purpose well, with the exception that the resulting image contrast is inevitably altered to proton-density weighting due to the transient-state signal behavior (12).…”

mentioning

confidence: 99%

Fat and water separation in balanced steady‐state free precession using the Dixon method

Huang

Chung

Wang

et al. 2004

Magnetic Resonance in Med

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The advantage of increased signal-to-noise ratio (SNR) efficiency in balanced steady-state free precession (SSFP) imaging (also denoted as true fast imaging in steady-state precession (TrueFISP), balanced fast field-echo (FFE), or fast imaging employing steady-state acquisition (FIESTA) by various manufacturers) has made this technique attractive for clinical applications. Examples of such applications include (but certainly are not limited to) cardiac imaging (1,2), angiography (3,4), gastrointestinal imaging (5,6), and fetal imaging (7). In certain situations, the signal from fat protons is a major source of interference that hinders our ability to interpret the image unambiguously. This is understood because fat has a higher T 2 /T 1 value compared to parenchymal tissues, which corresponds to bright steady-state signals on SSFP images (8). Therefore, for SSFP imaging applications intended to highlight fluids with large T 2 /T 1 values, such as angiography, myelography, and MR cholangiopancreatography (MRCP), it is essential to eliminate the fat signals.Fat suppression in SSFP imaging can be accomplished by using frequency-selective RF pulses in every TR, similarly to the conventional approach used in spin-echo imaging (5). This method increases TRs that are ordinarily short in generic SSFP sequences, and thus increases total scan time by a noticeable factor. Alternatively, magnetization preparation during the steady state, which refers to the addition of one fat-suppression pulse every several TRs, has also been shown to be effective (9). The latter method is advantageous in that the scan time is not significantly increased, which is beneficial for 3D examinations.Other methods, such as linear combination SSFP (10) and fluctuating equilibrium MR (11), have been proposed that make use of the SSFP spectral profiles manipulated by different RF phase schemes to selectively reconstruct different spectral species. For 2D imaging, the use of a single fat-suppression RF pulse followed by a centric-ordered SSFP readout should serve the same purpose well, with the exception that the resulting image contrast is inevitably altered to proton-density weighting due to the transient-state signal behavior (12).In a recent work, it was shown that SSFP images exhibit spin-echo-like behavior, such that spin isochromats at similar resonant frequencies show phase coherence at either 0°or 180°relative to the RF pulses at the time TR/2, the nominal TE in SSFP imaging (13). For off-resonance species, such as fat relative to water, the SSFP angle (i.e., the precession phase angle for the spin isochromats within one TR in the rotating frame) can be manipulated by adjusting the center reference frequency, which in turn determines the directional location for phase coherence in the rotating frame (13). This property leads naturally to the use of in-phase and out-of-phase images for Dixon addition/subtraction to achieve fat-water separation in SSFP imaging (14). In this study, we demonstrate the feasibility of separating fat and water sig...

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Are TrueFISP images T₂/T₁‐weighted?

Cited by 50 publications

References 16 publications

Double average parallel steady‐state free precession imaging: Optimized eddy current and transient oscillation compensation

Double average parallel steady‐state free precession imaging: Optimized eddy current and transient oscillation compensation

Fetal magnetic resonance imaging of normal spinal cord: Evaluating cord visualization and conus medullaris position by T2-weigted sequences

Fat and water separation in balanced steady‐state free precession using the Dixon method

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