Rapid Quantification of Mean Myocardial Wall Velocity in Ischemic Cardiomyopathy by Cardiac Magnetic Resonance: An Index of Cardiac Functional Abnormalities during the Cardiac Cycle

Abstract

Background: Characterization of regional Left Ventricular (LV) function in Heart Failure (HF) patients may have application in assessing response and choice of HF therapy. Methods: 4D LV endocardial function from cine cMR data in 12 NYHA Class III /IV Heart Failure (HF) patients with antero-apical aneurysms was compared against normal controls. The endocardial surface contours were extracted at each cardiac phase using Medviso Segment. An in-house plugin was used to compute a signed Hausdorff Distance (HD), establishing point-correspondences between endocardial segmentations at consecutive cardiac phases and tracking their surface motion throughout the cardiac cycle. The LV averaged myocardial velocity, was computed based on phase-to-phase displacement at several uniformly spaced endocardial surface points and the displacement histories of each point were recorded. The average and standard deviation in the endocardiumaveraged displacement history characteristic curves for the HF patients and normal controls were compared. Results: The endocardium-averaged phase-to-phase displacement history curves of HF cohort revealed diminished displacement magnitudes; and indistinct individual end-systolic and diastole instants with large standard deviations across the LV. When the cumulative phase to phase displacement plots for controls and HF patients were compared, there was a statistically significant difference between the two characteristic curves during the ejection phase, early filling phase of diastole, and the end diastolic phase. Conclusions: Shape-based Mean Myocardial Velocity (MMV) characterization constitutes a promising paradigm which may have application to prognosticate response to therapy.