MRI measurement of left ventricle myocardial strain on short axis in normal youth / 中华放射学杂志

ABSTRACT

Objective To learn the endocardial strain patterns of the left ventricles on the short-axis views in normal youth volunteers using feature tracking techniques on cine cardiac MR imaging,and to build up the reference ranges of strain peak and time to peak (TTP) for endocardial strain analysis.Methods Twenty-nine normal youth volunteers aged from 24-34 years old were enrolled in the study in march 2015.The Cine MR imaging were acquired using balance FFE sequence with 24 phases for each cardiac cycle.The standard short-axis imaging planes were basal,mid-cavity and apical levels and divided into 16 segments.The peaks and TTPs of myocardial displacement and its velocity,radial and circumferential strain and strain rate and its velocity in each segment were calculated using feature tracking techniques.The data with normal distribution were analyzed by ANOVA and Student-Newman-Keuls (SNK) method,and Kruskal-Wallis and Wilcoxon rank sum test were used for the data without normal distribution.Results The peaks and TTPs of radial strain and strain rate differed in 16-segmental levels and basal,middle and apical plane levels and had no concordant reference ranges.The circumferential strain and strain rate were homogeneous at basal and middle plane levels [(-27.09 ±9.51)％,(1.94 ±0.98)/s,respectively].Their TTPs were homogenous [0.38 (0.08)RR,0.54 (0.08)RR,respectively],and there were no significant differences in planar-segments or inter-segment level.Except for middle level,the peaks of radial displacement and velocity differed in basal and apical levels and had no concordant reference ranges.But radial velocity TTPs were homogeneous in all 16 segments [0.21 (0.04)RR].Except for the radial strain rate,TTPs showed no significant difference between basal level and middle level.The measurements at apical level revealed high variance.No regular pattern could be found on individual peak and TTP curves of velocity and strain rate.Conclusion The peaks and TTPs of radial strain are different in segmental and planar levels without a concordant reference range.The peaks and TFPs of circumferential strain and the radial velocity rTTPs are homogeneous in middle and apical plane level and have homogeneous reference range.