title: Fast tracking of cardiac motion using 3D-HARP.
abstract: Magnetic resonance (MR) tagging is capable of accurate, noninvasive quantification of regional myocardial function. Routine clinical use, however, is hindered by cumbersome and time-consuming postprocessing procedures. We propose a fast, semiautomatic method for tracking three-dimensional (3-D) cardiac motion from a temporal sequence of short- and long-axis tagged MR images. The new method, called 3-D-HARmonic Phase (3D-HARP), extends the HARP approach, previously described for two-dimensional (2-D) tag analysis, to 3-D. A 3-D material mesh model is built to represent a collection of material points inside the left ventricle (LV) wall at a reference time. Harmonic phase, a material property that is time-invariant, is used to track the motion of the mesh through a cardiac cycle. Various motion-related functional properties of the myocardium, such as circumferential strain and left ventricular twist, are computed from the tracked mesh. The correlation analysis of 3D-HARP and FINDTAGS + Tag Strain(E) Analysis (TEA), which are well-established tag analysis techniques, shows that the regression coefficients of circumferential strain (E(CC)) and twist angle are r2 = 0.8605 and r2 = 0.8645, respectively. The total time required for tracking 3-D cardiac motion is approximately 10 min in a 9 timeframe tagged MRI dataset and has the potential to be much faster.
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins School of Medicine, 601 N. Caroline St. JHOC 4240, Baltimore, MD 21287, USA. lipan@bme.jhu.edu
authors.forename: Li
authors.initials: L
authors.lastname: Pan
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Prince
authors.forename: João A C
authors.initials: JA
authors.lastname: Lima
authors.forename: Nael F
authors.initials: NF
authors.lastname: Osman
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003199:Computer Systems; D003287:Contrast Media; D005240:Feasibility Studies; D006352:Heart Ventricles / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008955:Models, Cardiovascular; D009068:Movement / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology; D016276:Ventricular Function
chemical_list: D003287:Contrast Media