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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.
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Purpose To measure the longitudinal and transverse strain and displacement parameters of each segment of long axis myocardium on cardiac MRI film images of normal young volunteers using feature tracking technique (FT), and to analyze the regularity of left ventricular long axis strain and establish peak and time to peak (TTP) reference range concerning the longitudinal and transverse strain and displacement. Materials and Methods Cardiac film images of 29 healthy volunteers aged 24 to 34 were collected using Philips Multiva 1.5T MRI scanner, including three typical long axis planes of the left ventricular long axis, left ventricular outflow tract, and four-chamber view. The MRI film images were analyzed drawing on myocardial feature tracking software TOMTEC, and the peak value and TTP of longitudinal and transverse strain and displacement of the 16 AHA segments excluding apex cordis were obtained thereby. The regularity of each parameter concerning the plane, layer, and segment was summarized and analyzed. Results The TTP of longitudinal strain, longitudinal displacement and transverse strain were consistent among each myocardial segment, which was a constant indicator in (41.24±12.51) ％ RR interphase. The peak value of longitudinal displacement was represented by apex cordis (2.56±0.89) mm < middle (6.09±2.03) mm < cardiac base (8.07±2.05) mm, and the peak value of transverse displacement was manifested as apex cordis (4.57±1.18) mm < middle (5.65±0.84) mm < cardiac base (8.48 ±1.18) mm, which was consistent with cardiac geometric deformation visually observed. The longitudinal strain showed consistency on 2CH-3CH-4CH plane, whose peak reference value was (-22.46±13.19)％; while the peak value of transverse strain displayed no consistency on different planes. Conclusion The longitudinal strain of the left ventricular on different planes has consistent peak value and TTP, suggesting good reference value.