Phase analysis detects heterogeneity of myocardial deformation on cine MRI

Abstract

Objectives: Myocardial scar will lead to heterogeneous left ventricular deformation. We hypothesized that a myocardial scar will display an elevated standard deviation (SD) of phase and that this effect could be compared with mechanical dispersion.

Design: Thirty patients (three women and 27 men) were investigated over 4-8 weeks after ST-elevation myocardial infarction treated with percutaneous coronary intervention. Seventeen had a scar area > 75% in at least one antero- or inferoseptal segment (scar) and 13 had a scar area < 1% (non-scar). The phase delays of velocity, displacement, and strain were measured in the longitudinal direction, tangential to the endocardial outline, and in the radial direction, perpendicular to the tangent.

Results: The SD of phase in radial measurements differentiated scar patients from those without scar (p < 0.01), while longitudinal measurements did so only for longitudinal strain. Likewise, the SD for radial measurements of time to peak for segmental velocity, displacement, and strain performed better than longitudinal measurements and equal to the results of phase.

Conclusion: Phase dispersion in deformation imaging may be used for detecting heterogeneous left ventricular contraction.

Keywords: cardiac function tests; magnetic resonance imaging; mechanical dispersion; myocardial strain; phase analysis.