Chemical shift‐induced phase errors in phase‐contrast MRI

Middione, Matthew J.; Ennis, Daniel B.

doi:10.1002/mrm.24262

Cited by 11 publications

(13 citation statements)

References 39 publications

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“…Several authors have previously studied the effects of chemical shift on phase‐contrast MRI . In this work, we have explored another relationship between flow and chemical shift.…”

Section: Discussionmentioning

confidence: 99%

Flow-induced signal misallocation artifacts in two-point fat-water chemical shift MRI

Rahimi

Holmes²,

Wang³

et al. 2014

Magn. Reson. Med.

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Purpose Two-point fat-water separation methods are increasingly being used for chest and abdominal MRI and have recently been introduced for use in MR angiography of the lower extremities. With these methods, flowing spins can accumulate unintended phase shifts between the echo times. The purpose of this study is to demonstrate that these phase shifts can lead to inaccurate signals in the water and fat images. Methods In vitro experiments were conducted at 1.5 T and 3.0 T using a stenosis-mimicking phantom and a computer-controlled pump to image a range of physiologically relevant velocities. Results In the phantom images acquired using bipolar readout gradients, fat-water signal inaccuracies were visible in regions of flow, with increasing severity as the flow rate was increased. Additionally, similar effects were observed in regions of high flow in clinical chest and liver exams. In the phantom images, the effect was eliminated by using a dual-pass method without bipolar readout gradients. Conclusion When using fat-water separation methods with bipolar readout gradients, phase shifts caused by the motion of spins can lead to signal inaccuracies in the fat and water images. These artifacts can be mitigated by employing approaches that do not use bipolar readout gradients.

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“…Several authors have previously studied the effects of chemical shift on phase‐contrast MRI . In this work, we have explored another relationship between flow and chemical shift.…”

Section: Discussionmentioning

confidence: 99%

Flow-induced signal misallocation artifacts in two-point fat-water chemical shift MRI

Rahimi

Holmes²,

Wang³

et al. 2014

Magn. Reson. Med.

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“…Off‐resonance due to field inhomogeneity and chemical shift leads to unwanted signal characteristics, which can lead to inaccuracies in quantitative measures such as LV strain measured by DENSE and rotation or the velocity of flowing blood measured by phase contrast . Off‐Resonance Insensitive‐ SPAMM (ORI‐SPAMM) was developed to negate the effects of off‐resonance accrued during motion encoding.…”

Section: Methodsmentioning

confidence: 99%

Intra‐ and interscan reproducibility using Fourier Analysis of STimulated Echoes (FAST) for the rapid and robust quantification of left ventricular twist

Reyhan

Kim

Brown

et al. 2013

Magnetic Resonance Imaging

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Purpose To assess the intra- and inter-scan reproducibility of LV twist using FAST. Assessing the reproducibility of the measurement of new magnetic resonance imaging (MRI) biomarkers is an important part of validation. Fourier Analysis of STimulated Echoes (FAST) is a new MRI tissue tagging method that has recently been shown to compare favorably to conventional estimates of left ventricular (LV) twist from cardiac tagged images, but with significantly reduced user interaction time. Materials and Methods Healthy volunteers (N=10) were scanned twice using FAST over one week. On Day-1 two measurements of LV twist were collected for intra-scan comparisons. Measurements for LV twist were again collected on Day-8 for inter-scan assessment. LV short-axis tagged images were acquired on a 3T scanner in order to ensure detectability of tags during early and mid-diastole. Peak LV twist is reported as mean±SD. Reproducibility was assessed using the concordance correlation coefficient (CCC) and the repeatability coefficient (RC) (95%-CI range). Results Mean peak twist measurements were 13.4±4.3° (Day-1, Scan-1), 13.6±3.7° (Day-1, Scan-2), and 13.0±2.7° (Day-8). Bland-Altman analysis resulted in intra- and inter-scan bias and 95%-CI of −0.6° [−1.0°, 1.6°] and 1.4° [−1.0°, 3.0°], respectively. The Bland-Altman RC for peak LV twist was 2.6° and 4.0° for intra- and inter-scan respectively. The CCC was 0.9 and 0.6 for peak LV twist for intra- and inter-scan respectively. Conclusion FAST is a semi-automated method that provides a quick and quantitative assessment of LV systolic and diastolic twist that demonstrates high intra-scan and moderate inter-scan reproducibility in preliminary studies.

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“…Complex-difference processing [ 62 ] and paraboloid fitting [ 63 ] reduce flow measurement errors, but are subject to limitations such as the assumption of laminar flow. In addition to these considerations, it has recently been recognized that partial volume from perivascular fat can cause chemical shift-induced velocity measurement errors, which can be minimized by imaging with high receiver bandwidth and choosing the TE such that fat and (stationary) blood signal are in-phase [ 64 ].…”

Section: Methodsmentioning

confidence: 99%

Cardiovascular magnetic resonance phase contrast imaging

Nayak

Nielsen

Bernstein

et al. 2015

Journal of Cardiovascular Magnetic Resonance

205

163

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Cardiovascular magnetic resonance (CMR) phase contrast imaging has undergone a wide range of changes with the development and availability of improved calibration procedures, visualization tools, and analysis methods. This article provides a comprehensive review of the current state-of-the-art in CMR phase contrast imaging methodology, clinical applications including summaries of past clinical performance, and emerging research and clinical applications that utilize today’s latest technology.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-015-0172-7) contains supplementary material, which is available to authorized users.

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Chemical shift‐induced phase errors in phase‐contrast MRI

Cited by 11 publications

References 39 publications

Flow-induced signal misallocation artifacts in two-point fat-water chemical shift MRI

Flow-induced signal misallocation artifacts in two-point fat-water chemical shift MRI

Intra‐ and interscan reproducibility using Fourier Analysis of STimulated Echoes (FAST) for the rapid and robust quantification of left ventricular twist

Cardiovascular magnetic resonance phase contrast imaging

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