Progress towards patient-specific computational flow modeling of the left heart via combination of magnetic resonance imaging with computational fluid dynamics.
A combined computational fluid dynamics (CFD) and magnetic resonance imaging (MRI) methodology has been developed to simulate blood flow in a subject-specific left heart. The research continues from earlier experience in modeling the human left ventricle using time-varying anatomical MR scans. Breathing artifacts are reduced by means of a MR navigator echo sequence with feedback to the subject, allowing a near constant breath-hold diaphragm position. An improved interactive segmentation technique for the long- and short-axis anatomical slices is used. The computational domain is extended to include the proximal left atrium and ascending aorta as well as the left ventricle, and the mitral and aortic valve orifices are approximately represented. The CFD results show remarkable correspondence with the MR velocity data acquired for comparison purposes, as well as with previously published in vivo experiments (velocity and pressure). Coherent vortex formation is observed below the mitral valve, with a larger anterior vortex dominating the late-diastolic phases. Some quantitative discrepancies exist between the CFD and MRI flow velocities, owing to the limitations of the MR dataset in the valve region, heart rate differences in the anatomical and velocity acquisitions, and to certain phenomena that were not simulated. The CFD results compare well with measured ranges in literature.
Saber
Nikoo R
NR
Mechanical Engineering Department, Imperial College of Science, Technology and Medicine, Exhibition Road, London, SW7 2BX United Kingdom. nikoo@caltech.edu
Wood
Nigel B
NB
Gosman
A D
AD
Merrifield
Robert D
RD
Yang
Guang-Zhong
GZ
Charrier
Clare L
CL
Gatehouse
Peter D
PD
Firmin
David N
DN
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D003198:Computer Simulation; D005260:Female; D020342:Finite Element Analysis; D006352:Heart Ventricles / Q000033:anatomy & histology*; D018056:Hemorheology / Q000379:methods; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008955:Models, Cardiovascular; D016276:Ventricular Function; D016277:Ventricular Function, Left / Q000502:physiology