Cardiac motion tracking using CINE harmonic phase (HARP) magnetic resonance imaging

Abstract

This article introduces a new image processing technique for rapid analysis of tagged cardiac magnetic resonance image sequences. The method uses isolated spectral peaks in SPAMMtagged magnetic resonance images, which contain information about cardiac motion. The inverse Fourier transform of a spectral peak is a complex image whose calculated angle is called a harmonic phase (HARP) image. It is shown how two HARP image sequences can be used to automatically and accurately track material points through time. A rapid, semiautomated procedure to calculate circumferential and radial Lagrangian strain from tracked points is described. This new computational approach permits rapid analysis and visualization of myocardial strain within 5-10 min after the scan is complete. Its performance is demonstrated on MR image sequences reflecting both normal and abnormal cardiac motion. Results from the new method are shown to compare very well with a previously validated tracking algorithm. Magn Reson Med 42:1048-1060,

Strain‐encoded (SENC) magnetic resonance imaging to evaluate regional heterogeneity of myocardial strain in healthy volunteers: Comparison with conventional tagging

“…In other MR tagging studies the interobserver variability was approximately the same as in our study using MR tagging (24,25). However, despite the use of harmonic phase (HARP) concepts (26), the data analysis of tagged images is still more time-consuming and is often confounded by noise artifacts due to inadequate image quality (19).…”

Real‐time fast strain‐encoded magnetic resonance imaging to evaluate regional myocardial function at 3.0 Tesla: Comparison to conventional tagging

“…1b). Tagged images were analyzed using the HARP software (Diagnosoft, Inc., Palo Alto, CA, USA), a method which enables the fast and reproducible determination of myocardial strain (5,17,18). Because the same number of segments was quantitatively analyzed by both techniques, a comparison of the analysis time spent was deemed appropriate.…”

Magnetic resonance imaging of regional cardiac function in the mouse

“…The HARmonic Phase (HARP) analysis was based on the method described by Osman et al [43]. First the two k-space data sets of the CSPAMM acquisitions with horizontal tag lines were subtracted from each other.…”

“…With these derivatives the Lagrange strain [43] was calculated. A cylindrical coordinate system of the left ventricle was defined by determining the midpoint of the left ventricular wall in the first CINE anatomical image.…”