Feature-tracking cardiovascular magnetic resonance as a novel technique for the assessment of mechanical dyssynchrony

Myocardial tagging using cardiovascular magnetic resonance (CMR) is the gold-standard for the assessment of myocardial mechanics. Feature-tracking cardiovascular magnetic resonance (FT-CMR) has been validated against myocardial tagging. We explore the potential of FT-CMR in the assessment of mechanical dyssynchrony, with reference to patients with cardiomyopathy and healthy controls.

Healthy controls (n=55, age: 42.9 ± 13 yrs, LVEF: 70 ± 5%, QRS: 88 ± 9 ms) and patients with cardiomyopathy (n=108, age: 64.7 ± 12 yrs, LVEF: 29 ± 6%, QRS: 147 ± 29 ms) underwent FT-CMR for the assessment of the circumferential (CURE) and radial (RURE) uniformity ratio estimate based on myocardial strain (both CURE and RURE: 0 to 1; 1=perfect synchrony)

CURE (0.79 ± 0.14 vs. 0.97 ± 0.02) and RURE (0.71 ± 0.14 vs. 0.91 ± 0.04) were lower in patients with cardiomyopathy than in healthy controls (both p<0.0001). CURE (area under the receiver-operator characteristic curve [AUC]: 0.96), RURE (AUC: 0.96) and an average of these (CURE:RUREAVG, AUC: 0.98) had an excellent ability to discriminate between patients with cardiomyopathy and controls (sensitivity 90%; specificity 98% at a cut-off of 0.89). The time taken for semi-automatically tracking myocardial borders was 5.9 ± 1.4 min.

Dyssynchrony measures derived from FT-CMR, such as CURE and RURE, provide almost absolute discrimination between patients with cardiomyopathy and healthy controls. The rapid acquisition of these measures, which does not require specialized CMR sequences, has potential for the assessment of mechanical dyssynchrony in clinical practice.