Inter-study reproducibility of cardiovascular magnetic resonance tagging

Abstract

BackgroundThe aim of this study is to determine the test-retest reliability of the measurement of regional myocardial function by cardiovascular magnetic resonance (CMR) tagging using spatial modulation of magnetization.MethodsTwenty-five participants underwent CMR tagging twice over 12 ± 7 days. To assess the role of slice orientation on strain measurement, two healthy volunteers had a first exam, followed by image acquisition repeated with slices rotated ±15 degrees out of true short axis, followed by a second exam in the true short axis plane. To assess the role of slice location, two healthy volunteers had whole heart tagging. The harmonic phase (HARP) method was used to analyze the tagged images. Peak midwall circumferential strain (Ecc), radial strain (Err), Lambda 1, Lambda 2, and Angle α were determined in basal, mid and apical slices. LV torsion, systolic and early diastolic circumferential strain and torsion rates were also determined.ResultsLV Ecc and torsion had excellent intra-, interobserver, and inter-study intra-class correlation coefficients (ICC range, 0.7 to 0.9). Err, Lambda 1, Lambda 2 and angle had excellent intra- and interobserver ICC than inter-study ICC. Angle had least inter-study reproducibility. Torsion rates had superior intra-, interobserver, and inter-study reproducibility to strain rates. The measurements of LV Ecc were comparable in all three slices with different short axis orientations (standard deviation of mean Ecc was 0.09, 0.18 and 0.16 at basal, mid and apical slices, respectively). The mean difference in LV Ecc between slices was more pronounced in most of the basal slices compared to the rest of the heart.ConclusionsIntraobserver and interobserver reproducibility of all strain and torsion parameters was excellent. Inter-study reproducibility of CMR tagging by SPAMM varied between different parameters as described in the results above and was superior for Ecc and LV torsion. The variation in LV Ecc measurement due to altered slice orientation is negligible compared to the variation due to slice location.Trial registrationThis trial is registered as NCT00005487 at National Heart, Lung and Blood institute.

Magnetic Resonance Imaging of Myocardial Deformation and Scarring in Coronary Artery Disease.

“…For the 11 patients without pathological signs, those values were 0.39 degrees/mm and 0.33 degrees/mm, respectively, which are similar to the values from recent studies of healthy volunteers [HARP: 0.37 degrees/mm [154]; DENSE: 0.34 degrees/mm [155]]. The mean torsion measured by FT among the 11 control patients was 0.22 degrees/mm, which is the same as the result of a previous FT study that measured it to be 0.23 degrees/mm [135].…”

Reproducibility of cine displacement encoding with stimulated echoes (DENSE) in human subjects

“…However, data from animal studies may not fully predict the reliability of DENSE for describing myocardial motion patterns in human subjects. Actually, existing results of human studies on similar MRI techniques, such as traditional MRI tagging or feature tracking, were unable to show optimal inter-study reproducibility for strain and its related measurements in all myocardial planes in human subjects (11, 16). We thought this variability may originate from two major sources, image analysis and image acquisition.…”

“…The twist (°, degree) of regional myocardial tissue, which is defined as the angle between lines connecting the center of LV and a moving myocardial pixel during the cardiac cycle, was also measured. The resulting LV torsion (°/mm) was defined as ΔΦ /D, where ΔΦ represents the difference of twist angles between the base and apex levels of the LV (averaged over 6 and 4 segments, respectively), and D denotes the longitudinal distance between two LV levels (11). All segmental measurements were averaged over three myocardial layers, including sub-endocardial, mid and sub-epicardial.…”

Association of Aortic Stiffness With Left Ventricular Remodeling and Reduced Left Ventricular Function Measured by Magnetic Resonance Imaging

“…LV torsion was defined by LV twist normalized by slice distance 12 . Early diastolic strain rate (EDSR) was identified as the first peak in the diastolic phase of the circumferential strain rate curve 19 .…”