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Real‐time imaging of two‐dimensional cardiac strain using a harmonic phase magnetic resonance imaging (HARP‐MRI) pulse sequence
Author(s) -
Sampath Smita,
Derbyshire J. Andrew,
Atalar Ergin,
Osman Nael F.,
Prince Jerry L.
Publication year - 2003
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.10509
Subject(s) - harp , pulse sequence , nuclear magnetic resonance , pulse (music) , magnetic resonance imaging , physics , harmonic , scanner , waveform , cardiac imaging , computer science , artificial intelligence , optics , acoustics , medicine , voltage , radiology , quantum mechanics , detector
The harmonic phase (HARP) method provides automatic and rapid analysis of tagged magnetic resonance (MR) images for quantification and visualization of myocardial strain. In this article, the development and implementation of a pulse sequence that acquires HARP images in real time are described. In this pulse sequence, a CINE sequence of images with 1‐1 spatial modulation of magnetization (SPAMM) tags are acquired during each cardiac cycle, alternating between vertical and horizontal tags in successive heartbeats. An incrementing train of imaging RF flip angles is used to compensate for the decay of the harmonic peaks due to both T 1 relaxation and the applied imaging pulses. The magnitude images displaying coarse anatomy are automatically reconstructed and displayed in real time after each heartbeat. HARP strain images are generated offline at a rate of four images per second; real‐time processing should be possible with faster algorithms or computers. A comparison of myocardial contractility in non‐breath‐hold and breath‐hold experiments in normal humans is presented. Magn Reson Med 50:154–163, 2003. © 2003 Wiley‐Liss, Inc.