In vitro validation of flow measurement with phase contrast MRI at 3 tesla using stereoscopic particle image velocimetry and stereoscopic particle image velocimetry-based computational fluid dynamics

Abstract

Purpose: To validate conventional phase-contrast MRI (PC-MRI) measurements of steady and pulsatile flows through stenotic phantoms with various degrees of narrowing at Reynolds numbers mimicking flows in the human iliac artery using stereoscopic particle image velocimetry (SPIV) as gold standard. Materials and Methods:A series of detailed experiments are reported for validation of MR measurements of steady and pulsatile flows with SPIV and CFD on three different stenotic models with 50%, 74%, and 87% area occlusions at three sites: two diameters proximal to the stenosis, at the throat, and two diameters distal to the stenosis.Results: Agreement between conventional spin-warp PC-MRI with Cartesian read-out and SPIV was demonstrated for both steady and pulsatile flows with mean Reynolds numbers of 130, 160, and 190 at the inlet by evaluating the linear regression between the two methods. The analysis revealed a correlation coefficient of > 0.99 and > 0.96 for steady and pulsatile flows, respectively. Additionally, it was found that the most accurate measures of flow by the sequence were at the throat of the stenosis (error < 5% for both steady and pulsatile mean flows). The flow rate error distal to the stenosis was primarily found to be a function of narrowing severity including dependence on proper Venc selection.Conclusion: SPIV and CFD provide excellent approaches to in vitro validation of new or existing PC-MRI flow measurement techniques.

Effects of heart valve prostheses on phase contrast flow measurements in Cardiovascular Magnetic Resonance – a phantom study

“…PC measurements are expected to be B 0 -insensitive, as two images containing the same flow-unrelated phase errors are subtracted from each other [27]. In this study, we could reproduce this finding in measurements where no flow was present – notwithstanding all tested metal containing prostheses markedly altered the local magnetic field.…”

Phase-contrast magnetic resonance imaging to assess renal perfusion: a systematic review and statement paper

“…Laser Doppler velocimetry, which measures the velocity component of a single particle at a "given point" perpendicular to the axis of the light beam, has demonstrated a wide range of accuracy for PC-MRI for both steady state and pulsatile flows [44][45][46]. Particle image velocimetry, which concurrently acquires 2D velocity information, has been used to validate PC-MRI flow through stenotic phantoms with various degrees of narrowing (r > 0.99 and > 0.96 for steady and pulsatile flows) [47].…”

Accuracy of phase-contrast velocimetry in systems with skewed intravoxel velocity distributions

“…Recent studies have focussed on evaluating the quantitative nature of PCV in more complex systems, for example by comparison with computational fluid dynamic simulations [28,29], particle image velocimetry [28,30] and laser Doppler velocimetry [31]. Several causes have been proposed for the observed errors including acceleration artefacts and phase contributions [32], flow related eddy current effects [24], voxel size related to partial-volume effects [33], relaxation effects [25] and other non-identified effects [24].…”