Analysis of velocity-based motion parameters in volunteers and patients with left ventricular dyssynchrony and myocardial infarction using magnetic resonance imaging

Abstract

About 30 % of patients receiving cardiac resynchronization therapy (CRT) devices, a sophisticated pacemaking therapy applied in patients with advanced stages of heart failure and left ventricular dyssynchrony, do not benefit from this therapy. Until now, no reliable predictors to therapy response have been found. Motion quantification parameters derived from velocity encoded magnetic resonance imaging (MRI) haven proven valuable, offering detailed information about myocardial motion processes in several studies. If these parameters were capable of distinguishing between specific myocardial contraction and relaxation patterns, they might be suitable to correctly identify CRT responders. The objective of this study therefore was to analyze the capability of 14 motion quantification parameters derived from tissue phase mapped (TPM) MRI to distinguish between healthy volunteers (HV; n = 41) and patients including myocardial infarction (STEMI; n = 17), dilated cardiomyopathy (DCM; n = 12) and DCM plus left ventricular asynchrony due to left bundle branch block (DCM + LBBB; n = 5). For the first time, velocity, angle based and strain based parameters were derived from the same TPM sequence. Acquisition of three TPM short axis slices (apical, equatorial and basal) on a 3 Tesla MRI and calculation of all 14 parameters was performed successfully. 13 of 14 parameters showed statistically significant differences between volunteer and patient cohorts. Left ventricular asynchrony in LBBB patients produced clearly aberrant values in the investigated parameters allowing significant distinction when compared to all other study cohorts. A wide distribution of values obtained from healthy volunteers was observed in some parameters. Motion-encoded MRI at 3 Tesla can be applied deriving motion quantification parameters to access left ventricular motion in volunteers and patients. New parameters were validated and results previously reported in the literature could be confirmed. Especially left ventricular dyssynchrony due to left bundle branch block produces characteristic values and several of the respected parameters are reliably capable of detecting specific motion patterns as well as separation from healthy, undamaged myocardium in volunteers. A future age-matched clinical study including more patients with left ventricular asynchrony of various etiologies and patients fulfilling CRT indication criteria is necessary to finalize the verification process of the investigated motion quantification parameters.