Validation and reproducibility of cardiovascular 4D-flow MRI from two vendors using 2 × 2 parallel imaging acceleration in pulsatile flow phantom and in vivo with and without respiratory gating

Abstract

Background 4D-flow magnetic resonance imaging (MRI) is increasingly used. Purpose To validate 4D-flow sequences in phantom and in vivo, comparing volume flow and kinetic energy (KE) head-to-head, with and without respiratory gating. Material and Methods Achieva dStream (Philips Healthcare) and MAGNETOM Aera (Siemens Healthcare) 1.5-T scanners were used. Phantom validation measured pulsatile, three-dimensional flow with 4D-flow MRI and laser particle imaging velocimetry (PIV) as reference standard. Ten healthy participants underwent three cardiac MRI examinations each, consisting of cine-imaging, 2D-flow (aorta, pulmonary artery), and 2 × 2 accelerated 4D-flow with (Resp+) and without (Resp−) respiratory gating. Examinations were acquired consecutively on both scanners and one examination repeated within two weeks. Volume flow in the great vessels was compared between 2D- and 4D-flow. KE were calculated for all time phases and voxels in the left ventricle. Results Phantom results showed high accuracy and precision for both scanners. In vivo, higher accuracy and precision ( P < 0.001) was found for volume flow for the Aera prototype with Resp+ (–3.7 ± 10.4 mL, r = 0.89) compared to the Achieva product sequence (–17.8 ± 18.6 mL, r = 0.56). 4D-flow Resp− on Aera had somewhat larger bias (–9.3 ± 9.6 mL, r = 0.90) compared to Resp+ ( P = 0.005). KE measurements showed larger differences between scanners on the same day compared to the same scanner at different days. Conclusion Sequence-specific in vivo validation of 4D-flow is needed before clinical use. 4D-flow with the Aera prototype sequence with a clinically acceptable acquisition time (<10 min) showed acceptable bias in healthy controls to be considered for clinical use. Intra-individual KE comparisons should use the same sequence.

Ideal Bolus Geometry Predicted from In vitro Pulsatile Flow Phantom and Artificial Neural Networks for the Optimization of Image Acquisition Protocols for Aortic Contrast-Enhanced Computed Tomography Angiography

“…The main strength of this study was its use of an in vitro aortic phantom connected to a closed-circuit-flow system that simulated human aortic velocity and pressure [24][25][26][27][28][29]. Phantom studies that simulate human circulation enable repeated CT scans without the risk of radiation damage and iodine exposure in human subjects and can provide thousands of datasets by manipulating multiple variables.…”

“…The conditions of pump and phantom devices were carefully manipulated while monitoring velocity and pressure to simulate human circulation, since the reliability of this feasibility study depends on the degree of agreement between the in vitro phantom simulation and actual human circulation. Although fine adjustments in the pump and phantom devices were made to produce bolus geometry mimicking human circulation [24][25][26][27][28][29], the differences might had affected the experimental results. Despite the precisions revealed from the repeated scanning or the trends found in this phantom study, particular cautions need to be taken in the context of clinical interpretation, and this study's results need to be confirmed in a successive clinical study.…”

A phantom study comparing radial trajectories for accelerated cardiac 4D flow MRI against a particle imaging velocimetry reference

“…There are several reasons for this residual error. While the realistic anatomical model is a strength of this work, it also 36 432 333 334 437 743 (9) Speed (20) 85 (17) 95 (14) 110 (18) 140 (1.8) 86 (17) 98 (28) 130 (31) 180 (24) 240 (36) WSS Corr. Coeff.…”

Flow quantification dependency on background phase correction techniques in 4D‐flow MRI

“…Three dimensional cine phase‐contrast MRI (4D‐flow MRI) is used as a regular research modality in cardiac MRI and is becoming more widely adopted as a utility for clinical assessment . Obstacles to its full adoption in routine clinical practice include difficulties in postprocessing and variability among studies investigating its reliability and accuracy of measurements . Vascular flow‐volume measurements are an integral component of cardiovascular MR examinations.…”

“…1,2 Obstacles to its full adoption in routine clinical practice include difficulties in postprocessing and variability among studies investigating its reliability and accuracy of measurements. 3,4 Vascular flow-volume measurements are an integral component of cardiovascular MR examinations. The 4D-flow MRI enables retrospective flow-volume measurements at any vessel location following the conclusion of the imaging study.…”