Comparison of strain imaging techniques in CRT candidates: CMR tagging, CMR feature tracking and speckle tracking echocardiography

Abstract

Parameters using myocardial strain analysis may predict response to cardiac resynchronization therapy (CRT). As the agreement between currently available strain imaging modalities is unknown, three different modalities were compared. Twenty-seven CRT-candidates, prospectively included in the MARC study, underwent cardiac magnetic resonance (CMR) imaging and echocardiographic examination. Left ventricular (LV) circumferential strain was analysed with CMR tagging (CMR-TAG), CMR feature tracking (CMR-FT), and speckle tracking echocardiography (STE). Basic strain values and parameters of dyssynchrony and discoordination obtained with CMR-FT and STE were compared to CMR-TAG. Agreement of CMR-FT and CMR-TAG was overall fair, while agreement between STE and CMR-TAG was often poor. For both comparisons, agreement on discoordination parameters was highest, followed by dyssynchrony and basic strain parameters. For discoordination parameters, agreement on systolic stretch index was highest, with fair intra-class correlation coefficients (ICC) (CMR-FT: 0.58, STE: 0.55). ICC of septal systolic rebound stretch (SRS_sept) was poor (CMR-FT: 0.41, STE: 0.30). Internal stretch factor of septal and lateral wall (ISF_sep-lat) showed fair ICC values (CMR-FT: 0.53, STE: 0.46), while the ICC of the total LV (ISF_LV) was fair for CMR-FT (0.55) and poor for STE (ICC: 0.32). The CURE index had a fair ICC for both comparisons (CMR-FT: 0.49, STE 0.41). Although comparison of STE to CMR-TAG was limited by methodological differences, agreement between CMR-FT and CMR-TAG was overall higher compared to STE and CMR-TAG. CMR-FT is a potential clinical alternative for CMR-TAG and STE, especially in the detection of discoordination in CRT-candidates.

Keywords: Cardiac resynchronization therapy; Discoordination; Dyssynchrony; Feature tracking; Myocardial tagging; Speckle tracking echocardiography; Strain.

Fig. 1

Overview of imaging techniques and corresponding myocardial strain analysis. Examples of imaging techniques (top row) and resulting strain signals (bottom row) of one specific patient. Each column represents a single technique with the corresponding strain results. Examples of derived parameters are shown per graph. Basic strain parameters are indicated with a number, dyssynchrony and discoordination parameters are indicated with a character. Strain signals of the septum (black line) and lateral wall (grey line) are given, with the aortic valve closure (grey vertical line) as end of systole. CMR cardiac magnetic resonance imaging, AVC aortic valve closure, AVC strain strain value at aortic valve closure, TTP _max time to maximal peak shortening, onset-delay time delay between onset of shortening of septal and lateral wall, peak-delay septal to lateral wall delay of TTP_max, SRS _sept systolic rebound stretch of the septum, SSI systolic stretch index, ISF _sep–lat internal stretch fraction of septal and lateral wall

Fig. 2

LBBB pattern categorization. Septal strain pattern categorization and distribution of strain patterns found by the three imaging techniques. The distribution per imaging technique is given vertical in the upper panel. The cross-over of patients from CMR tagging to speckle tracking echocardiography and CMR feature tracking is displayed by arrows. The thickness of the arrows matches the number of patients crossing over. The number of patients crossing over is also given by a number in each arrow. Specific examples of the three patterns are given in the lower panel. Black curve: septal strain, grey dashed curved: lateral wall strain. CMR cardiac magnetic resonance imaging, LBBB-1 double peak shortening, LBBB-2 predominant stretch, LBBB-3 pseudo-normal shortening, n number of patients

Fig. 3

Bland–Altman plots of basic strain parameters. Bland–Altman plots for CMR-TAG versus CMR-FT and CMR-TAG versus STE of three basic strain parameters. The mean of two techniques is plotted on the x-axis and the difference on the y-axis. The mean difference is displayed as a solid red line, while the limits of agreement are displayed as dotted red lines. Septal values are given as dots, while lateral wall values are given as crosses. AVC strain strain at aortic valve closure time, Peak strain highest negative peak strain value, TTP _max time to maximal peak strain, CMR cardiac magnetic resonance imaging, TAG tagging, FT feature tracking, STE speckle tracking echocardiography

Fig. 4

Bland–Altman plots of regional discoordination parameters. Bland–Altman plots for CMR-TAG versus CMR-FT and CMR-TAG versus STE of regional discoordination parameters (i.e. SRS_sept, SSI and ISF_sep–lat). The mean value of one patient analysed with the two techniques is plotted on the x-axis and the difference on the y-axis. The mean difference is displayed as a solid red line, while the limits of agreement are displayed as dotted red lines. SRS _sept septal systolic rebound stretch, SSI systolic stretch index, ISF _sep–lat internal stretch factor of septum and lateral wall, CMR cardiac magnetic resonance imaging, TAG tagging, FT feature tracking, STE speckle tracking echocardiography

Fig. 5

Bland–Altman plots of discoordination parameters of the total LV. Bland–Altman plots for CMR-TAG versus CMR-FT and CMR-TAG versus STE of two discoordination parameters, obtained from the total LV. The mean value of one patient analysed with the two techniques is plotted on the x-axis and the difference on the y-axis. The mean difference is displayed as a solid red line, while the limits of agreement are displayed as dotted red lines. ISF _LV internal stretch factor of the total LV, CURE circumferential uniformity ratio estimates, LV left ventricle, CMR cardiac magnetic resonance imaging, TAG tagging, FT feature tracking, STE speckle tracking echocardiography