Cine flow measurements using phase contrast with undersampled projections: In vitro validation and preliminary results in vivo

Wentland, Andrew L.; Korosec, Frank R.; Vigen, Karl K.; Wieben, Oliver; Fine, Jason P.; Grist, Thomas M.

doi:10.1002/jmri.20715

Cited by 9 publications

(10 citation statements)

References 17 publications

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“…MR images depict kidney structure, which allows for the visualization of the integrity of the cortex and medulla, the size of the kidney, and any potential extra-renal abnormalities. MR imaging also may be used to map the renal vasculature and diagnose vascular anomalies, such as renal artery stenosis [6]. Newer MR imaging techniques can be used to assess the filtration capacity of glomeruli, blood flow within the kidneys, and oxygen bioavailability [7-9].…”

Section: Introductionmentioning

confidence: 99%

Quantitative MR Measures of Intrarenal Perfusion in the Assessment of Transplanted Kidneys

et al. 2009

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Rationale and Objectives The purpose of this study was to evaluate prospectively a gadolinium-based perfusion technique for intrarenal blood flow in transplanted kidneys and to determine if magnetic resonance (MR) measurements of intrarenal perfusion could be used to differentiate between normal-functioning kidney allografts and allografts with acute tubular necrosis (ATN) or acute rejection. Materials and Methods Twenty-one subjects were enrolled within four months of receiving a kidney transplant. A biopsy was performed on subjects to diagnose each allograft as having either ATN or acute rejection. A group of subjects with normal functioning transplants were also enrolled in our study. MR perfusion images were acquired on a 1.5T MRI system within 48 hours after biopsy using an echo planar, T2*-weighted sequence and an injection of gadodiamide contrast agent administered at a dose of 0.1mmol/kg. Scan parameters were: TR/TE/flip=1000msec/30msec/60°, FOV=340×340mm, matrix=128×64, slice thickness=10mm, and temporal resolution=1.0sec. Cortical and medullary blood flow values were calculated. Results Medullary blood flow values were significantly (p=0.02) lower in allografts undergoing acute rejection (121±41 mL/100g/min) compared to normal-functioning allografts (221±96 mL/100g/min) and those with ATN (247±124 mL/100g/min). Cortical blood flow values were also significantly (p=0.03) reduced in allografts with acute rejection (243±116 mL/100g/min) compared to those with normal function (413±116 mL/100g/min). Conclusion Preliminary results indicate that MR perfusion techniques may provide a means of determining noninvasively the viability of renal allografts, potentially alleviating the need for biopsy in some patients.

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Section: Introductionmentioning

confidence: 99%

Quantitative MR Measures of Intrarenal Perfusion in the Assessment of Transplanted Kidneys

et al. 2009

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“…However, radial undersampling may reduce SNR and produce streak artifacts. Radial undersampling factors of up to 12 with good accuracy have been recently reported in a validation study for renal artery flow 15 .…”

Section: Introductionmentioning

confidence: 89%

“…With the RPC method, k-space is sampled as a series of radial projections, each traversing through the center of k-space 9, 15 . Spatial resolution is determined by the sample spacing along each radial projection.…”

Section: Introductionmentioning

confidence: 99%

“…In certain imaging applications, a high signal-to-noise ratio can be achieved even if the number of acquired projections is significantly less than the number of projections required to fulfill the Nyquist sampling criterion. Therefore, the RPC acquisition allows for higher spatial resolution per unit time than that achievable with spin-warp encoding methods 9, 15 . However, radial undersampling may reduce SNR and produce streak artifacts.…”

Section: Introductionmentioning

confidence: 99%

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Accuracy and Reproducibility of Phase-Contrast MR Imaging Measurements for CSF Flow

Wentland¹,

Wieben²,

Korosec³

et al. 2010

AJNR Am J Neuroradiol

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Background/Purpose The purpose of this study was to evaluate the accuracy and reproducibility of two fast phase contrast MR techniques for measuring CSF flow. Materials/Methods Velocities were calculated from Radially-sampled Phase Contrast (RPC) and Cartesian-based Phase Contrast (CPC) images of fluid flowing in a tube at constant velocity. Error and the coefficient of variation (COV) were computed for average and peak velocities. Additionally, measurements of sinusoidally fluctuating flow and of CSF flow in five normal volunteers were acquired with the RPC and CPC acquisitions. Results For constant velocity experiments, error for the RPC and CPC acquisitions averaged +1.15 and +8.91% and COVs averaged 1.29 and 3.01%, respectively. For peak velocities of 12.6 cm/sec or larger, error with RPC or CPC ranged from −33.3 to −36.9% and COV was 0–4% for RPC and 1–7% for CPC. For peak velocities of 6.4 cm/sec or less, RPC and CPC overestimated velocity by greater than 250%. For fluctuating flow, both acquisitions showed similar flow patterns. In volunteer studies, peak systolic and diastolic velocities were not significantly different. Conclusion The RPC and CPC sequences measure velocities on the order of CSF flow with an average error of 9% or better. The two techniques significantly overestimate peak velocities below 6.4 cm/sec, with maximum errors of 209% and 276% and maximum COVs of 100% and 73% for the RPC and CPC sequences, respectively. Measurements of CSF velocities in human volunteers and of sinusoidally fluctuating phantom velocities did not differ significantly between the two techniques.

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“…THE QUANTITATIVE MEASUREMENT of blood flow by using MRI has been a topic of research for over 20 years. At present, blood flow measurements are largely performed by two-dimensional phase contrast magnetic resonance (PC-MR), and numerous studies of the accuracy of MR quantitative flow measurement based on both steady flows and realistic pulsatile flows have been conducted (1)(2)(3)(4)(5)(6). In conventional PC-MR (Con PC-MR), linear gradients are used to generate a signal phase shift proportional to each spin's velocity (7).…”

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confidence: 99%

Numerical and experimental study of a novel phase contrast magnetic resonance (PC‐MR) imaging technique: Sparse interleaved referencing PC‐MR imaging

Doyle

Rayarao

et al. 2008

Magnetic Resonance Imaging

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Purpose:To use numerical simulation and experimental approaches to introduce a novel phase contrast magnetic resonance (PC-MR) data processing technique termed Sparse Interleaved Referencing PC-MR, with potential to improve accuracy, temporal resolution, and signal-to-noise ratio (SNR) of PC-MR data. Materials and Methods:Computational fluid dynamics data were generated for a two-chamber orifice flow model simulating valvular regurgitation. The numerical results were validated and used to simulate conventional and Sparse Interleaved Referencing PC-MR data acquisitions. Common data sets were processed using conventional and Sparse Interleaved Referencing approaches and quantitative errors in velocity-time waveforms were measured and compared. In vitro phantom jet flow data and in vivo ascending aorta data were acquired and used to simulate Sparse Interleaved Referencing PC-MR. Results:The Sparse Interleaved Referencing PC-MR data showed significantly better representation of the velocity-time waveform in three areas: (i) lower root-mean-square errors (9.0 Ϯ 1.0% versus 24.0 Ϯ 0.2%; P Ͻ 0.005), (ii) simulation of conventionally processed data showed a pattern of peak velocity overestimation, which was experimentally demonstrated in in vitro data, whereas overestimation of peak velocity was dramatically attenuated using Sparse Interleaved Referencing (2.8 Ϯ 0.4% versus 16.9 Ϯ 6.4%, P Ͻ 0.005), and (iii) compared with the conventional scan, an average of 119.4 Ϯ 26.6% (P Ͻ 0.005) SNR was realized in in vitro and in vivo Sparse Interleaved Referencing PC-MR data. Conclusion:Simulation and in vitro/in vivo results show that Sparse Interleaved Referencing PC-MR processed data in pulsatile and jet flow showed higher accuracy, better peak velocity representation, and improved SNR compared with the data processed using the conventional PC-MR method.

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Cine flow measurements using phase contrast with undersampled projections: In vitro validation and preliminary results in vivo

Cited by 9 publications

References 17 publications

Quantitative MR Measures of Intrarenal Perfusion in the Assessment of Transplanted Kidneys

Quantitative MR Measures of Intrarenal Perfusion in the Assessment of Transplanted Kidneys

Accuracy and Reproducibility of Phase-Contrast MR Imaging Measurements for CSF Flow

Numerical and experimental study of a novel phase contrast magnetic resonance (PC‐MR) imaging technique: Sparse interleaved referencing PC‐MR imaging

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