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3D left ventricular strain from unwrapped harmonic phase measurements
Author(s) -
Venkatesh Bharath Ambale,
Gupta Himanshu,
Lloyd Steven G.,
Dell 'Italia Louis,
Denney Thomas S.
Publication year - 2010
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22099
Subject(s) - harp , strain (injury) , phase (matter) , harmonic , magnetic resonance imaging , cardiac cycle , physics , biomedical engineering , materials science , computer science , artificial intelligence , nuclear magnetic resonance , medicine , anatomy , acoustics , cardiology , radiology , quantum mechanics
Purpose: To validate a method for measuring 3D left ventricular (LV) strain from phase‐unwrapped harmonic phase (HARP) images derived from tagged cardiac magnetic resonance imaging (MRI). Materials and Methods: A set of 40 human subjects were imaged with tagged MRI. In each study the HARP phase was computed and unwrapped in each short‐axis and long‐axis image. Inconsistencies in unwrapped phase were resolved using branch cuts manually placed with a graphical user interface. 3D strain maps were computed for all imaged timeframes in each study. The strain from unwrapped phase (SUP) and displacements were compared to those estimated by a feature‐based (FB) technique and a HARP technique. Results: 3D strain was computed in each timeframe through systole and mid‐diastole in ≈30 minutes per study. The standard deviation of the difference between strains measured by the FB and the SUP methods was less than 5% of the average of the strains from the two methods. The correlation between peak circumferential strain measured using the SUP and HARP techniques was over 83%. Conclusion: The SUP technique can reconstruct full 3D strain maps from tagged MR images through the cardiac cycle in a reasonable amount of time and user interaction compared to other 3D analysis methods. J. Magn. Reson. Imaging 2010;31:854–862. ©2010 Wiley‐Liss, Inc.