Phase‐contrast velocimetry with simultaneous fat/water separation

Johnson, Kevin M.; Wieben, Oliver; Samsonov, Alexey

doi:10.1002/mrm.22355

Cited by 5 publications

(14 citation statements)

References 38 publications

(45 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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.

View full text Add to dashboard Cite

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.

show abstract

“…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.

View full text Add to dashboard Cite

show abstract

“…The study was conducted on a clinical 3T scanner (Discovery MR 750, GE Healthcare, Waukesha, WI) with a 32-chanel body coil (NeoCoil, Pewaukee, WI). 4D velocity mapping was achieved using a cardiac-gated time-resolved 3D radially undersampled phase contrast (PC) acquisition (5-point PC-VIPR) [11] with increased velocity sensitivity performance. [4],[11] Acquisition parameters included: imaging volume: 32×32×24cm excitation with spherical encoding, 1.25mm acquired isotropic spatial resolution, TR/TE=6.4/2.2ms.…”

Section: Methodsmentioning

confidence: 99%

Surgical planning for living donor liver transplant using 4D flow MRI, computational fluid dynamics and in vitro experiments

Rutkowski

Reeder

Fernández

et al. 2017

Computer Methods in Biomechanics and Biomedical Engineering: Im

View full text Add to dashboard Cite

This study used magnetic resonance imaging (MRI), computational fluid dynamics (CFD) modeling, and in vitro experiments to predict patient-specific alterations in hepatic hemodynamics in response to partial hepatectomy in living liver donors. 4D Flow MRI was performed on three donors before and after hepatectomy and models of the portal venous system were created. Virtual surgery was performed to simulate (1) surgical resection and (2) post-surgery vessel dilation. CFD simulations were conducted using in vivo flow data for boundary conditions. CFD results showed good agreement with in vivo data, and in vitro experimental values agreed well with imaging and simulation results. The post-surgery models predicted an increase in all measured hemodynamic parameters, and the dilated virtual surgery model predicted post-surgery conditions better than the model that only simulated resection. The methods used in this study have potential significant value for the surgical planning process for the liver and other vascular territories.

show abstract

“…Fat‐water separated PC‐MRI should be considered to solve for both the phase of fat and the phase of water, thereby eliminating the contamination of the water phase by perivascular fat phase (31). The physics and mathematics of this problem are interesting, but the clinical utility of this approach is uncertain.…”

Section: Discussionmentioning

confidence: 99%

“…The results of this study focused entirely on Cartesian‐based trajectories. Non‐Cartesian trajectories, such as radial and spiral, lead to distortion and blurring of the fat signal (31, 32). This blurring effect may not be as resilient to the proposed chemical shift reduction strategy (HBW‐TE IN ) and may necessitate the use of spatial‐spectral pulses (33) or non‐Cartesian‐based multipoint fat‐water separation techniques (e.g., IDEAL (31) or Dixon (34))…”

Section: Discussionmentioning

confidence: 99%

Chemical shift‐induced phase errors in phase‐contrast MRI

Middione

Ennis

2012

Magnetic Resonance in Med

View full text Add to dashboard Cite

Phase contrast magnetic resonance imaging (PC-MRI) is subject to numerous sources of error, which decrease clinical confidence in the reported measures. This work outlines how stationary perivascular fat can impart a significant chemical shift induced PC-MRI measurement error using computational simulations, in vitro, and in vivo experiments. This chemical shift error does not subtract in phase difference processing, but can be minimized with proper parameter selection. The chemical shift induced phase errors largely depend on both the receiver bandwidth (BW) and the TE. Both theory and an in vivo comparison of the maximum difference in net forward flow between vessels with and without perivascular fat indicated that the effects of chemically shifted perivascular fat are minimized by the use of high BW (814 Hz/px) and an in-phase TE (HBW-TEIN). In healthy volunteers (N=10) HBW-TEIN significantly improves intrapatient net forward flow agreement compared to low BW (401 Hz/px) and a mid-phase TE as indicated by significantly decreased measurement biases and limits of agreement for the ascending aorta (1.8±0.5 mL vs. 6.4±2.8 mL, P=0.01), main pulmonary artery (2.0±0.9 mL vs. 11.9±5.8 mL, P=0.04), the left pulmonary artery (1.3±0.9 mL vs. 5.4±2.5 mL, P=0.003), and all vessels (1.7±0.8 mL vs. 7.2±4.4 mL, P=0.001).

show abstract

Phase‐contrast velocimetry with simultaneous fat/water separation

Cited by 5 publications

References 38 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

Surgical planning for living donor liver transplant using 4D flow MRI, computational fluid dynamics and in vitro experiments

Chemical shift‐induced phase errors in phase‐contrast MRI

Contact Info

Product

Resources

About