Cardiac CINE imaging with IDEAL water‐fat separation and steady‐state free precession

Reeder, Scott B.; Markl, Michael; Yu, Hong; Hellinger, Jeffrey C.; Herfkens, Robert J.; Pelc, Norbert J.

doi:10.1002/jmri.20327

Cited by 69 publications

(75 citation statements)

References 34 publications

(48 reference statements)

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“…Image separation methods have many applications (28)(29)(30)(31)(32). Identification of tissue types is simplified by identifying tissues in any single image rather than assessing relative contrast between neighboring tissues in images weighted by intrinsic MR parameters such as T 1 , T 2 , or spin density.…”

Section: Discussionmentioning

confidence: 99%

Magnetic resonance separation imaging using a divided inversion recovery technique (DIRT)

Goldfarb

2010

Magn. Reson. Med.

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The divided inversion recovery technique is an MRI separation method based on tissue T 1 relaxation differences. When tissue T 1 relaxation times are longer than the time between inversion pulses in a segmented inversion recovery pulse sequence, longitudinal magnetization does not pass through the null point. Prior to additional inversion pulses, longitudinal magnetization may have an opposite polarity. Spatial displacement of tissues in inversion recovery balanced steadystate free-precession imaging has been shown to be due to this magnetization phase change resulting from incomplete magnetization recovery. In this paper, it is shown how this phase change can be used to provide image separation. A pulse sequence parameter, the time between inversion pulses (T180), can be adjusted to provide water-fat or fluid separation. Example water-fat and fluid separation images of the head, heart, and abdomen are presented. The water-fat separation performance was investigated by comparing image intensities in short-axis divided inversion recovery technique images of the heart. Fat, blood, and fluid signal was suppressed to the background noise level. Additionally, the separation performance was not affected by main magnetic field inhomogeneities. Magn Reson Med 63:1007-1014, 2010. V C 2010 Wiley-Liss, Inc. Key words: MRI; separation imaging; fat; lipid; fluid; myocardial infarction; pulse sequence; inversion recovery; bSSFP Tissue characterization in MRI is mostly performed using a visual assessment of image contrast generated by contrast agents or intrinsic magnetic relaxation time differences. MR images with pixel intensities weighted by T 1 or T 2 relaxation times are most commonly used. Additionally, preparation pulses can generate a variety of image contrasts between tissues. For example, fat saturation (1), magnetization transfer contrast radiofrequency pulses (2), or diffusion gradient pulses (3) may be added to impose specific image contrasts. The difference in pixel intensities allows identification of and discrimination between diseased and healthy tissues using a single image.MR image separation techniques provide multiple images of the same imaging plane with pixels separated by an intrinsic tissue parameter. Water-fat separation (4) provides two images. Pixels composed primarily of lipids are displayed in the fat image and the other pixels composed primarily of water are displayed in the second image. Water-fat separation is most commonly performed using the chemical shift between water and fat nuclei. Image separation can also be performed using other parameters such as T 1 relaxation times or T 1 -weighted imaging pixel intensity (5). In T 1 -weighted spoiled gradient echo images, fat usually has the brightest signal and water-fat separation can be performed using a simple image intensity threshold.Recently, an artifact was identified during late gadolinium-enhanced myocardial infarct imaging using an inversion recovery balanced steady-state free precession (IR-bSSFP) technique (6,7). This artifact is a spa...

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Section: Discussionmentioning

confidence: 99%

Magnetic resonance separation imaging using a divided inversion recovery technique (DIRT)

Goldfarb

2010

Magn. Reson. Med.

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“…Fat and muscle volumes were estimated by MRI imaging using a single channel, standard head coil on a whole-body clinical Signa Excite 3T Tesla scanner system (General Electric). Three-point fat -water separation imaging (IDEAL, 3D-FSPGR, field of view 380 mm, echo time TE ¼ 3.372 ms, image matrix 256 Â 256, bandwidth 31.25 Hz, flip angle 108, 40 slices with no gap between neighbouring slices, slice thickness 1.5 mm) provided by the scanner manufacturer was used to acquire and quantify the water and fat content in each imaged volume element (voxel; Reeder et al 2005Reeder et al , 2007. This enabled heterogeneities in the main magnetic field to be compensated for (Dixon 1984;Glover & Schneider 1991), and near-isotropic imaging, with image voxel size of 1.5 Â 1.5 Â 1.5 mm 3 .…”

Section: Methodsmentioning

confidence: 99%

Whether depositing fat or losing weight, fish maintain a balance

et al. 2009

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In fish, the relative amount of tissues of different densities changes significantly over short periods throughout the year, depending on the availability of food, nutrition and their developmental status, such as sexual maturation. If a land-living animal accumulates fat it influences not only its general state of health, but also markedly increases its energy expenditure for locomotion owing to the force of gravity. On a body submerged in water, this force, which acts on the centre of gravity (COG), is counterbalanced by a lifting force that is negligible in air and which acts on the centre of buoyancy (COB). Any difference in the longitudinal positions of the two centres will therefore result in pitching moments that must be counteracted by body or fin movements. The displacement of the COG away from the COB is a result of tissues of different density (e.g. bones and fat) not being distributed homogeneously along the body axis. Moreover, the proportions of tissues of different densities change significantly with feeding status. It is still unknown whether these changes produce a displacement of the COG and thus affect the hydrostatic stability of fish. Analysis of computed tomography and magnetic resonance imaging images of Atlantic herring, Atlantic salmon and Atlantic mackerel reveals that the COG is fairly constant in each species, although we recorded major interspecies differences in the relative amount of fat, muscle and bone. We conclude that the distribution of different tissues along the body axis is very closely adjusted to the swimming mode of the fish by keeping the COG constant, independent of the body fat status, and that fish can cope with large variations in energy intake without jeopardizing their COG and thus their swimming performance.

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“…This approach is based on the work of Brittain et al (6). Imaging parameters included BW ϭ Ϯ100 kHz, TR ϭ 4.7 ms, TE ϭ 1.1/1.7/ Finally, cardiac CINE SSFP imaging acquired at 1.5 T using a retrospectively gated CINE SSFP sequence, and a four-element phased array torso coil was performed in a normal volunteer (20). Imaging parameters included FOV ϭ 32 cm, slice ϭ 8 mm, 224 ϫ 128 (134 point fractional readout, echo fraction ϭ 0.60), and BW ϭ Ϯ125 kHz.…”

Section: Methodsmentioning

confidence: 99%

“…This would help shorten TR, which would reduce potential banding artifacts, and improve sequence efficiency. Finally, partial k-space acquisitions could potentially be combined with parallel imaging methods that are already used with water-fat separation methods (25)(26)(27). This would facilitate even further reductions in minimum scan times.…”

Section: Discussionmentioning

confidence: 99%

Homodyne reconstruction and IDEAL water–fat decomposition

Reeder

Hargreaves

et al. 2005

Magnetic Resonance in Med

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Multipoint water-fat separation methods have received renewed interest because they provide uniform separation of water and fat despite the presence of B 0 and B 1 field inhomogeneities. Unfortunately, full-resolution reconstruction of partial k-space acquisitions has been incompatible with these methods. Conventional homodyne reconstruction and related algorithms are commonly used to reconstruct partial k-space data sets by exploiting the Hermitian symmetry of k-space in order to maximize the spatial resolution of the image. In doing so, however, all phase information of the image is lost. The phase information of complex source images used in a waterfat separation acquisition is necessary to decompose water from fat. In this work, homodyne imaging is combined with the IDEAL (iterative decomposition of water and fat with echo asymmetry and least squares estimation) method to reconstruct full resolution water and fat images free of blurring. Reliable separation of water from fat using chemical-shiftbased approaches has shown renewed interest in recent years (1-6), as it provides uniform separation of water from fat despite the presence of B 0 and B 1 field inhomogeneities. These methods typically acquire three images, each with slightly different echo times (TE), and analytical (2,3) or least squares (7) methods are then used to decompose these "source" images into separate water and fat images. Extension to multicoil applications has also been described recently (5,7).Partial k-space acquisitions in the readout direction are important for applications that must reduce the minimum TE, first moment phase shifts from motion or flow in the readout direction, and the minimum TR. Short TRs are essential for good image quality for SSFP water-fat separation applications to prevent banding artifacts while maintaining high spatial resolution in the readout direction (7-10). Partial readout acquisitions would also be important for rapid SPGR water-fat separation methods that require short TE and TR.The threefold increase in image acquisition time for waterfat separation methods is often problematic for many applications, particularly when oversampling strategies in the phase encoding direction ("no phase wrap") are used to prevent aliasing. Although water-fat separation methods are highly SNR efficient (2,7), there is a threefold increase in scan time compared with a conventional fat-saturated exam. In order to prevent aliasing in the phase encoding direction, additional interleaved lines of k-space can be acquired to increase the field of view in the phase encoding direction. Doubling the number of acquired lines of k-space, for example, would result in a sixfold increase in the minimum scan time of a conventional fat-saturated exam. This lengthy scan time is unacceptable for many clinical settings. Reductions in scan time through partial k y acquisitions would be very helpful toward addressing this problem.Partial k-space acquisitions have seen very limited use with water-fat separation methods. Homodyne reconstruction ...

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Cardiac CINE imaging with IDEAL water‐fat separation and steady‐state free precession

Cited by 69 publications

References 34 publications

Magnetic resonance separation imaging using a divided inversion recovery technique (DIRT)

Magnetic resonance separation imaging using a divided inversion recovery technique (DIRT)

Whether depositing fat or losing weight, fish maintain a balance

Homodyne reconstruction and IDEAL water–fat decomposition

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