- Poster presentation
- Open Access
Assessment of energy loss in aortic stenosis using Bayesian multipoint phase-contrast MRI
© Binter et al; licensee BioMed Central Ltd. 2013
- Published: 30 January 2013
- Aortic Valve
- Turbulent Kinetic Energy
- Valve Replacement
- Aortic Stenosis
- Aortic Valve Replacement
Aortic stenosis is the most prevalent valvular heart disease. The current gold standard for determination of the disease severity is Doppler echocardiography, but the decision for valve replacement is mostly based on the patient experiencing symptoms . Doppler echocardiography measures the velocity across the valve, which is only indirectly linked to the energy loss associated with a diseased valve. It has recently been proposed that energy loss can be quantified directly by employing Bayesian multipoint phase-contrast MRI (PC-MRI) . In this work we present preliminary data acquired in patients with severe aortic stenosis.
A Bayesian multipoint velocity encoding sequence  was implemented on a 3T system (Philips Healthcare, Best, The Netherlands). A navigated and cardiac-triggered 3D gradient echo sequence with spatial and temporal resolution of 2.5 x 2.5 x 2.5 mm3 and 36 ms was used. A total of 10 velocity encoding points was acquired resulting in approximately 8 min scan time excluding navigator efficiency. Approval of the local Ethics Review Board was obtained and patients were recruited upon informed consent. Energy loss was computed based on the ratio of turbulent to mean kinetic energy taking reflow into account as proposed previously . The pressure gradients were computed analogous to Doppler echocardiography using the modified Bernoulli equation: PG = 4vmax2.
Flow parameters for both patients as determined by MRI and Doppler echocardiography.
Bayesian multipoint PC-MRI
Peak total TKE
Energy loss index
Mean pressure gradient
Aortic valve area
Mean pressure gradient
Bayesian multipoint PC-MRI permits concurrent mapping of both mean kinetic and turbulent kinetic energy in patients and allows the assessment of relative energy loss and pressure gradients associated with aortic valve stenosis. The energy loss index was found to be approximately 8-fold higher as compared to healthy subjects  and may hold promise to serve as a novel marker for grading valve disease.
Christian Binter was supported by the National Competence Center in Biomedical Imaging Switzerland.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.