9 research outputs found
Evaluation of aortic stenosis severity using 4D flow jet shear layer detection for the measurement of valve effective orifice area.
Aims: The objective of this study was to evaluate the potential of 4D flow MRI to assess valve effective orifice
area (EOA) in patients with aortic stenosis as determined by the jet shear layer detection (JSLD) method.
Methods and Results: An in-vitro stenosis phantom was used for validation and in-vivo imaging was
performed in 10 healthy controls and 40 patients with aortic stenosis. EOA was calculated by the JSLD method
using standard 2D phase contrast MRI (PC-MRI) and 4D flow MRI measurements (EOAJSLD-2D and EOAJSLD-4D,
respectively). As a reference standard, the continuity equation was used to calculate EOA (EOACE) with the 2D
PC-MRI velocity field and compared to the EOAJSLD measurements. The in-vitro results exhibited excellent
agreement between flow theory (EOA = 0.78 cm2) and experimental measurement (EOAJSLD-4D = 0.78 ±0.01 cm2) for peak velocities ranging from 0.9 to 3.7 m/s. In-vivo results showed good correlation and
agreement between EOAJSLD-2D and EOACE (r = 0.91, p b 0.001; bias: -0.01 ± 0.38 cm2; agreement limits:
0.75 to -0.77 cm2), and between EOAJSLD-4D and EOACE (r = 0.95, p b 0.001; bias: -0.09 ± 0.26 cm2;
limits: 0.43 to -0.62 cm2).
Conclusion: This study demonstrates the feasibility of measuring EOAJSLD using 4D flow MRI. The technique
allows for optimization of the EOA measurement position by visualizing the 3D vena contracta, and avoids
potential sources of EOACE measurement variability