Whole‐heart chemical shift encoded water–fat MRI

Taviani, Valentina; Hernando, Diego; François, Christopher J.; Shimakawa, Ann; Vigen, Karl K.; Nagle, Scott K.; Schiebler, Mark L.; Grist, Thomas M.; Reeder, Scott B.

doi:10.1002/mrm.24982

Cited by 8 publications

(8 citation statements)

References 42 publications

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“…11 However, breath-hold requirements may reduce the comfort of pregnant patients and the corresponding scan time constraints may limit the achievable spatial resolution and image signal-to-noise ratio (SNR). Respiratory-gated 12,13 and freebreathing non-Cartesian acquisition techniques 14,15 have been applied in body 3D CSE-MRI during free-breathing and shown to be motion robust.…”

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confidence: 99%

Evaluation of a motion‐robust 2D chemical shift‐encoded technique for R2* and field map quantification in ferumoxytol‐enhanced MRI of the placenta in pregnant rhesus macaques

Zhu

Reeder

Johnson

et al. 2019

Magnetic Resonance Imaging

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Background 3D chemical shift‐encoded (CSE)‐MRI techniques enable assessment of ferumoxytol concentration but are unreliable in the presence of motion. Purpose To evaluate a motion‐robust 2D‐sequential CSE‐MRI for R2* and B0 mapping in ferumoxytol‐enhanced MRI of the placenta. Study Type Prospective. Animal Model Pregnant rhesus macaques. Field Strength/Sequence 3.0T/CSE‐MRI. Assessment 2D‐sequential CSE‐MRI was compared with 3D respiratory‐gated CSE‐MRI in placental imaging of 11 anesthetized animals at multiple timepoints before and after ferumoxytol administration, and in ferumoxytol phantoms (0 μg/mL–440 μg/mL). Motion artifacts of CSE‐MRI in 10 pregnant women without ferumoxytol administration were assessed retrospectively by three blinded readers (4‐point Likert scale). The repeatability of CSE‐MRI in seven pregnant women was also prospectively studied. Statistical Tests Placental R2* and boundary B0 field measurements (ΔB0) were compared between 2D‐sequential and 3D respiratory‐gated CSE‐MRI using linear regression and Bland–Altman analysis. Results In phantoms, a slope of 0.94 (r2 = 0.99, concordance correlation coefficient ρ = 0.99), and bias of –4.8 s‐1 (limit of agreement [LOA], –41.4 s‐1, +31.8 s‐1) in R2*, and a slope of 1.07 (r2 = 1.00, ρ = 0.99) and bias of 11.4 Hz (LOA –12.0 Hz, +34.8 Hz) in ΔB0 were obtained in 2D CSE‐MRI compared with 3D CSE‐MRI for reference R2* ≤390 s‐1. In animals, a slope of 0.92 (r2 = 0.97, ρ = 0.98) and bias of –2.2 s‐1 (LOA –55.6 s‐1, +51.3 s‐1) in R2*, and a slope of 1.05 (r2 = 0.95, ρ = 0.97) and bias of 0.4 Hz (LOA –9.0 Hz, +9.7 Hz) in ΔB0 were obtained. In humans, motion‐impaired R2* maps in 3D CSE‐MRI (Reader 1: 1.8 ± 0.6, Reader 2: 1.3 ± 0.7, Reader 3: 1.9 ± 0.6), while 2D CSE‐MRI was motion‐free (Reader 1: 2.9 ± 0.3, Reader 2: 3.0 ± 0, Reader 3: 3.0 ± 0). A mean difference of 0.66 s‐1 and coefficient of repeatability of 9.48 s‐1 for placental R2* were observed in the repeated 2D CSE‐MRI. Data Conclusion 2D‐sequential CSE‐MRI provides accurate R2* and B0 measurements in ferumoxytol‐enhanced placental MRI of animals in the presence of respiratory motion, and motion‐robustness in human placental imaging. Level of Evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:580–592.

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confidence: 99%

Evaluation of a motion‐robust 2D chemical shift‐encoded technique for R2* and field map quantification in ferumoxytol‐enhanced MRI of the placenta in pregnant rhesus macaques

Zhu

Reeder

Johnson

et al. 2019

Magnetic Resonance Imaging

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“…Experiments were conducted after obtaining informed consent and IRB approval using a clinical 1.5 Tesla (T) scanner (HDxt, v16.0, GE Healthcare, Waukesha, WI) and a clinical 3T scanner (MR750 v22.0, GE Healthcare, Waukesha, WI). Cardiac datasets were acquired in 28 subjects using a 3D free‐breathing, navigated, cardiac‐gated four‐echo SPGR sequence . Data were also acquired in the ankle from six volunteers and in the brachial plexus from five volunteers (one volunteer was scanned twice, on different days) using a 3D three‐echo SPGR sequence.…”

Section: Methodsmentioning

confidence: 99%

Improving chemical shift encoded water–fat separation using object‐based information of the magnetic field inhomogeneity

Sharma

Artz

Hernando

et al. 2014

Magnetic Resonance in Med

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Purpose The purpose of this work was to improve the robustness of existing chemical shift encoded water-fat separation methods by incorporating object-based information of the B0 field inhomogeneity. Theory The primary challenge in water-fat separation is the estimation of phase shifts that arise from B0 field inhomogeneity, which is composed of the background field and susceptibility-induced field. The susceptibility-induced field can be estimated if the susceptibility distribution is known or can be approximated. In this work, the susceptibility distribution is approximated from the source images using the known susceptibility values of water, fat, and air. The field estimate is then demodulated from the source images prior to water-fat separation. Methods Chemical shift encoded source images were acquired in anatomical regions that are prone to water-fat swaps. The images were processed using algorithms from the ISMRM Fat-Water Toolbox, with and without the object-based field map information. The estimates were compared to examine the benefit of using the object-based field map information. Results Multiple cases are shown in which water-fat swaps were avoided by using the object-based information of the B0 field map. Conclusion Object-based information of the B0 field may improve the robustness of existing chemical shift encoded water-fat separation methods.

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“…The effects of B 0 inhomogeneity are modeled as linear phase shifts applied to each of the spectral components at each echo time. Using this model, CSE fat‐water techniques have been used for many applications using both gradient and spin echo acquisitions .…”

Section: Theorymentioning

confidence: 99%

Utilization of a balanced steady state free precession signal model for improved fat/water decomposition

Bancroft

Strigel

Hernando

et al. 2015

Magnetic Resonance in Med

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Purpose Chemical shift based fat/water decomposition methods such as IDEAL are frequently used in challenging imaging environments with large B0 inhomogeneity. However, they do not account for the signal modulations introduced by a balanced SSFP acquisition. Here we demonstrate improved performance when the bSSFP frequency response is properly incorporated into the multi-peak spectral fat model used in the decomposition process. Theory Balanced SSFP allows for rapid imaging but also introduces a characteristic frequency response featuring periodic nulls and pass bands. Fat spectral components in adjacent pass bands will experience bulk phase offsets and magnitude modulations that change the expected constructive and destructive interference between the fat spectral components. Methods A bSSFP signal model was incorporated into the fat / water decomposition process and used to generate images of a fat phantom, and bilateral breast and knee images in four normal volunteers at 1.5 Tesla. Results Incorporation of the bSSFP signal model into the decomposition process improved the performance of the fat/water decomposition. Conclusion Incorporation of this model allows rapid bSSFP imaging sequences to utilize robust fat/water decomposition methods such as IDEAL. While only one set of imaging parameters were presented, the method is compatible with any field strength or TR.

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Whole‐heart chemical shift encoded water–fat MRI

Cited by 8 publications

References 42 publications

Evaluation of a motion‐robust 2D chemical shift‐encoded technique for R2* and field map quantification in ferumoxytol‐enhanced MRI of the placenta in pregnant rhesus macaques

Evaluation of a motion‐robust 2D chemical shift‐encoded technique for R2* and field map quantification in ferumoxytol‐enhanced MRI of the placenta in pregnant rhesus macaques

Improving chemical shift encoded water–fat separation using object‐based information of the magnetic field inhomogeneity

Utilization of a balanced steady state free precession signal model for improved fat/water decomposition

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