Turbulent Kinetic Energy Measurement Using Phase Contrast MRI for Estimating the Post-Stenotic Pressure Drop: In Vitro Validation and Clinical Application

• Published in: PloS one Vol. 11; no. 3; p. e0151540
• Main Authors: Ha, Hojin, Kim, Guk Bae, Kweon, Jihoon, Huh, Hyung Kyu, Lee, Sang Joon, Koo, Hyun Jung, Kang, Joon-Won, Lim, Tae-Hwan, Kim, Dae-Hee, Kim, Young-Hak, Kim, Namkug, Yang, Dong Hyun
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 15-03-2016; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Aged, 80 and over; Anatomy, Cross-Sectional; Aorta; Aortic valve; Aortic Valve Insufficiency - diagnostic imaging; Aortic Valve Insufficiency - physiopathology; Aortic Valve Stenosis - diagnostic imaging; Aortic Valve Stenosis - physiopathology; Biology and Life Sciences; Blood flow; Blood Flow Velocity; Blood Pressure; Cardiology; Coronary vessels; Echocardiography; Echocardiography, Doppler; Energy consumption; Energy loss; Energy measurement; Feasibility Studies; Female; Fluid dynamics; Fourier Analysis; Heart diseases; Heart Valve Prosthesis; Heart valves; Hemodynamics; Hemorheology; Humans; Imaging, Three-Dimensional; Impact tests; Kinetic energy; Kinetics; Laser-Doppler Flowmetry - methods; Laser-Doppler Flowmetry - standards; Magnetic resonance; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Measurement; Measurement methods; Mechanical engineering; Medical examination; Medicine; Medicine and Health Sciences; Middle Aged; NMR; Nuclear magnetic resonance; Particle image velocimetry; Phantoms, Imaging; Phase contrast; Physical Sciences; Physiological aspects; Pressure; Pressure drop; Printing, Three-Dimensional; Research and Analysis Methods; Rheumatic heart disease; Stenosis; Studies; Turbulence; Turbulence measurement; Turbulent flow; Turbulent kinetic energy; Velocity measurement; South Korea
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0151540

Although the measurement of turbulence kinetic energy (TKE) by using magnetic resonance imaging (MRI) has been introduced as an alternative index for quantifying energy loss through the cardiac valve, experimental verification and clinical application of this parameter are still required.
The goal of this study is to verify MRI measurements of TKE by using a phantom stenosis with particle image velocimetry (PIV) as the reference standard. In addition, the feasibility of measuring TKE with MRI is explored.
MRI measurements of TKE through a phantom stenosis was performed by using clinical 3T MRI scanner. The MRI measurements were verified experimentally by using PIV as the reference standard. In vivo application of MRI-driven TKE was explored in seven patients with aortic valve disease and one healthy volunteer. Transvalvular gradients measured by MRI and echocardiography were compared.
MRI and PIV measurements of TKE are consistent for turbulent flow (0.666 < R2 < 0.738) with a mean difference of -11.13 J/m3 (SD = 4.34 J/m3). Results of MRI and PIV measurements differ by 2.76 ± 0.82 cm/s (velocity) and -11.13 ± 4.34 J/m3 (TKE) for turbulent flow (Re > 400). The turbulence pressure drop correlates strongly with total TKE (R2 = 0.986). However, in vivo measurements of TKE are not consistent with the transvalvular pressure gradient estimated by echocardiography.
These results suggest that TKE measurement via MRI may provide a potential benefit as an energy-loss index to characterize blood flow through the aortic valve. However, further clinical studies are necessary to reach definitive conclusions regarding this technique.