Highly accelerated compressed-sensing 4D flow for intracardiac flow assessment
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Abstract
Background: Four-dimensional (4D) flow MRI allows for the quantification of complex flow patterns; however, its clinical
use is limited by its inherently long acquisition time. Compressed sensing (CS) is an acceleration technique that provides
substantial reduction in acquisition time.
Purpose: To compare intracardiac flow measurements between conventional and CS-based highly accelerated 4D flow
acquisitions.
Study Type: Prospective.
Subjects: Fifty healthy volunteers (28.0 7.1 years, 24 males).
Field Strength/Sequence: Whole heart time-resolved 3D gradient echo with three-directional velocity encoding (4D flow)
with conventional parallel imaging (factor 3) as well as CS (factor 7.7) acceleration at 3 T.
Assessment: 4D flow MRI data were postprocessed by applying a valve tracking algorithm. Acquisition times, flow vol umes (mL/cycle) and diastolic function parameters (ratio of early to late diastolic left ventricular peak velocities [E/A] and
ratio of early mitral inflow velocity to mitral annular early diastolic velocity [E/e0
]) were quantified by two readers.
Statistical Tests: Paired-samples t-test and Wilcoxon rank sum test to compare measurements. Pearson correlation coeffi cient (r), Bland–Altman-analysis (BA) and intraclass correlation coefficient (ICC) to evaluate agreement between techniques
and readers. A P value < 0.05 was considered statistically significant.
Results: A significant improvement in acquisition time was observed using CS vs. conventional accelerated acquisition
(6.7 1.3 vs. 12.0 1.3 min). Net forward flow measurements for all valves showed good correlation (r > 0.81) and agree ment (ICCs > 0.89) between conventional and CS acceleration, with 3.3%–8.3% underestimation by the CS technique.
Evaluation of diastolic function showed 3.2%–17.6% error: E/A 2.2 [1.9–2.4] (conventional) vs. 2.3 [2.0–2.6] (CS), BA bias
0.08 [ 0.81–0.96], ICC 0.82; and E/e0 4.6 [3.9–5.4] (conventional) vs. 3.8 [3.4–4.3] (CS), BA bias 0.90 [ 2.31–0.50],
ICC 0.89.
Data Conclusion: Analysis of intracardiac flow patterns and evaluation of diastolic function using a highly accelerated 4D
flow sequence prototype is feasible, but it shows underestimation of flow measurements by approximately 10%.
Evidence Level: 2
Technical Efficacy: Stage 1
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Journal of magnetic resonance imaging, Version of Record (VoR), Wiley-Liss, New York, NY, 2022, https://doi.org/10.1002/jmri.28484