Influence of contrast agent and spatial resolution on myocardial strain results using feature tracking MRI.

OBJECTIVES

Feature tracking for assessing myocardial strain from cardiac magnetic resonance (CMR) cine images detects myocardial deformation abnormalities with prognostic implication, e.g., in myocardial infarction and cardiomyopathy. Standards for image acquisition and processing are not yet available. Study aim was analyzing the influence of spatial resolution and contrast agent on myocardial strain results.

METHODS

Seventy-five patients underwent CMR for analyzing peak systolic circumferential, longitudinal, and radial strain. Group A included n = 50 with normal left ventricular ejection fraction, no wall motion abnormality, and no fibrosis on late enhancement imaging. Group B included n = 25 with chronic myocardial infarct. For feature tracking, steady-state free precession cine images were acquired repeatedly. (1) Native standard cine (spatial resolution 1.4 × 1.4 × 8 mm). (2) Native cine with lower spatial resolution (2.0 × 2.0 × 8 mm). (3) Cine equal to variant 1 acquired after administration of gadoteracid.

RESULTS

Lower spatial resolution was associated with elevated longitudinal strain (- 21.7% vs. - 19.8%; p < 0.001) in viable myocardium in group A, and with elevated longitudinal (- 17.0% vs. - 14.3%; p = 0.001), circumferential (- 18.6% vs. - 14.6%; p = 0.002), and radial strain (36.8% vs. 31.0%; p = 0.013) in infarcted myocardium in group B. Gadolinium administration was associated with reduced circumferential (- 21.4% vs. - 22.3%; p = 0.001) and radial strain (44.4% vs. 46.9%; p = 0.016) in group A, whereas strain results of the infarcted tissue in group B did not change after contrast agent administration.

CONCLUSIONS

Variations in spatial resolution and the administration of contrast agent may influence myocardial strain results in viable and partly in infarcted myocardium. Standardized image acquisition seems important for CMR feature tracking.

KEY POINTS

• Feature tracking is used for calculating myocardial strain from cardiac magnetic resonance (CMR) cine images. • This prospective study demonstrated that CMR strain results may be influenced by spatial resolution and by the administration of gadolinium-based contrast agent. • The results underline the need for standardized image acquisition for CMR strain analysis, with constant imaging parameters and without contrast agent.