Semiautomated method for noise reduction and background phase error correction in MR phase velocity data

Purpose: To compare longitudinal myocardial velocity and time to peak longitudinal velocity obtained with magnetic resonance phase velocity mapping (MR-PVM) and tissue Doppler imaging (TDI), and to assess the reproducibility of each method. Materials and Methods:Longitudinal myocardial velocity was measured by TDI and MR-PVM in 10 normal volunteers and 10 patients with dyssynchrony. The reproducibility of MR-PVM and TDI was assessed on repeated measurements in the 10 normal volunteers.Results: MR and TDI measurements of longitudinal myocardial velocity correlated well (r ϭ 0.86) in both normal subjects and patients with dyssynchrony. However, myocardial velocities measured with MR consistently exceeded velocities measured with TDI. MR and TDI agreed strongly in measuring the time to peak velocity (r ϭ 0.97). The reproducibility of TDI and MR-PVM appeared similar in measuring peak velocities (13.1% vs. 11.0%, respectively; P ϭ NS) and time to peak velocity (9.1% vs. 5.7%, respectively; P ϭ NS). Conclusion:Excellent correlation and reproducibility were observed between MR-PVM and TDI in measuring longitudinal myocardial velocity and time to peak velocity in both normal subjects and patients with dyssynchrony.

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“…Background phase error was removed using a least-squares fitted plane (23). Longitudinal velocity toward the apex was defined as positive.…”

Section: Mr Methodsmentioning

confidence: 99%

Comparison of myocardial velocities obtained with magnetic resonance phase velocity mapping and tissue doppler imaging in normal subjects and patients with left ventricular dyssynchrony

Delfino

Bhasin

Cole

et al. 2006

Magnetic Resonance Imaging

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“…Postprocessing of data included automated noise filtering and eddy current correction (20). Visualization of anatomy and spatially registered blood flow in 3D was performed using a commercially available software package (EnSight; Apex, CEI, NC, USA).…”

Section: Data Analysis and 3d Visualizationmentioning

confidence: 99%

Visualization of iliac and proximal femoral artery hemodynamics using time‐resolved 3D phase contrast MRI at 3T

Frydrychowicz

Winterer

Zaitsev

et al. 2007

Magnetic Resonance Imaging

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Purpose:To demonstrate the feasibility of time-resolved 3D MR velocity mapping at 3 Tesla for the visualization of vascular hemodynamics in normal iliac and femoral arteries. Materials and Methods:Electrocardiographically (ECG) synchronized three-dimensional (3D) CINE phase-contrast MRI with three-directional flow encoding was adapted to analyze flow in peripheral arteries at 3T. Visualization of peripheral arterial hemodynamics within the acquired data volume included 3D streamlines and time-resolved 3D particle traces within the major vessels and localized analysis of flow profiles using 2D-vector graphs. Data was visually compared to results from color-coded duplex ultrasound (US).Results: Global and detailed local blood flow characteristics were successfully analyzed in all subjects. In agreement with US findings, normal laminar flow patterns without flow acceleration or disturbances were visualized in all healthy individuals. In an exemplary patient measurement multiple segmental flow accelerations could be demonstrated. MRI additionally revealed complex helical flow alterations distal to a moderate stenosis. Conclusion:Due to the full spatial and temporal coverage of the arteries of interest, 3D CINE phase contrast MRI at 3T is a promising tool for the evaluation of vascular hemodynamics in peripheral arteries. Future methodological improvements will be directed to improve spatial and temporal resolution as well as quantitative data analysis. Moreover, the technique will have to be evaluated in patients in comparison to standard diagnostic tools.

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“…Based on the phase values of the pixels in the station ary water surrounding the model, a plane containing the phase offsets was created through two-dimensional regression analysis, as previously described in detail (18,21). Subtraction of this error plane from each initial phase image resulted in a series of new corrected phase images.…”

Section: Image and Data Analysismentioning

confidence: 99%

Quantification of mitral regurgitation with MR phase‐velocity mapping using a control volume method

Chatzimavroudis

Oshinski

Pettigrew

et al. 1998

Magnetic Resonance Imaging

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Reliable diagnosis and quantification of mitral regurgitation are important for patient management and for optimizing the time for surgery. Previous methods have often provided suboptimal results. The aim of this in vitro study was to evaluate MR phase‐velocity mapping in quantifying the mitral regurgitant volume (MRV) using a control volume (CV) method. A number of contiguous slices were acquired with all three velocity components measured. A CV was then selected, encompassing the regurgitant orifice. Mass conservation dictates that the net inflow into the CV should be equal to the regurgitant flow. Results showed that a CV, the boundary voxels of which excluded the region of flow acceleration and aliasing at the orifice, provided accurate measurements of the regurgitant flow. A smaller CV provided erroneous results because of flow acceleration and velocity aliasing close to the orifice. A large CV generally provided inaccurate results because of reduced velocity sensitivity far from the orifice. Aortic outflow, orifice shape, and valve geometry did not affect the accuracy of the CV measurements. The CV method is a promising approach to the problem of quantification of the MRV.

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Semiautomated method for noise reduction and background phase error correction in MR phase velocity data

Cited by 364 publications

References 18 publications

Comparison of myocardial velocities obtained with magnetic resonance phase velocity mapping and tissue doppler imaging in normal subjects and patients with left ventricular dyssynchrony

Comparison of myocardial velocities obtained with magnetic resonance phase velocity mapping and tissue doppler imaging in normal subjects and patients with left ventricular dyssynchrony

Visualization of iliac and proximal femoral artery hemodynamics using time‐resolved 3D phase contrast MRI at 3T

Quantification of mitral regurgitation with MR phase‐velocity mapping using a control volume method

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