Preliminary investigation of multiparametric strain Z‐score (MPZS) computation using displacement encoding with simulated echoes (DENSE) and radial point interpretation method (RPIM)

Abstract

Purpose To describe and assess an automated, normalization method for identifying sentinel (septal) regions of myocardial dysfunction in non-ischemic, non-valvular dilated cardiomyopathy (DCM) using an unprecedented combination of the Navigator-gated 3D Spiral Displacement Encoding with Stimulated Echoes (DENSE) MRI, Radial Point Interpolation (RPIM) and Multiparametric Strain Z-Score (MPZS). Materials and Methods Navigator-gated 3D Spiral DENSE, in a 1.5 Tesla MRI machine, was used for acquiring the displacement encoded complex images, MR Analytical Software System (MASS) for automated boundary detection and automated meshfree RPIM for left-ventricular (LV) myocardial strain computation to analyze MPZS in 36 subjects (with N=17 DCM patients). Pearson’s r correlation established relations between global/sentinel MPZS and EF. The time taken for combined RPIM-MPZS computations was recorded. Results Maximum MPZS differences were seen between anteroseptal and posterolateral regions in the base (2.0 ± 0.3 versus 0.9 ± 0.5) and the mid-wall (2.1 ± 0.4 versus 1.0 ± 0.4). These regional differences were found to be consistent with historically documented septal injury in non-ischemic DCM. Correlations were 0.6 between global MPZS and EF, and 0.7 between sentinel MPZS and EF. The time taken for combined RPIM-MPZS computations per subject was 18.9 ± 5.9 seconds. Conclusions Heterogeneous contractility found in the sentinel regions with the current automated MPZS computation scheme and the correlation found between MPZS and EF may lead to the creation of a new clinical metric in LV DCM surveillance.

Can post-chemotherapy cardiotoxicity be detected in long-term survivors of breast cancer via comprehensive 3D left-ventricular contractility (strain) analysis?

“…2) which was seen in several patients. The above dysfunctional pattern was also reported in our previous studies as being distinctly characteristic to DCM [36,50]. Similarities not found with existing studies include not finding a reduction in peak systolic radial strain that have been reported as high as 40% or in peak systolic circumferential strain between 11 and 17% [9][10][11][12]16,17].…”

“…This effect was seen in the ~1.5-2° non-normalized (to ventricular height) difference in torsion found between the agematched subset and entire healthy subgroup. Overall, it is important to note that detection of subclinical contractile abnormalities was based on comparing two different subpopulations, patients and healthy subjects, which was possible due to the chamber quantifications and normal strain measurements in the database of healthy subjects we have built over several validation studies [33,50,52,53].…”

Introduction to a mechanism for automated myocardium boundary detection with displacement encoding with stimulated echoes (DENSE)

“…Additionally, we have precedence in having used the DENSE sequence for analyzing strain in dilated cardiomyopathy patients where scans were completed with minimum discomfort to patients. 18, 19,39 In this, the 15 min acquisition window (the timing breakdown for which is given in the acquisition section) can be justified for DENSE as it provides the critical displacement and strain data which a faster SSFP sequence cannot. Furthermore, research is now underway for faster DENSE imaging using technologies such as compressed sense with parallel imaging that deliver high quality images while reducing scan time.…”

“…One of the main similarities to the Spottiswoode et al method lies in regard to finding material point displacements from displacement vectors with tails originating at a reference point on the myocardial boundary and in how only vectors closest in angular orientation and magnitude are used for approximating the location of a new boundary point. 10, 12,18,19,39 The existing 2D technique also applies some effective noise removing steps associated with motion-based trajectories, including fitting of each trajectory with periodic Fourier series basis functions, which was a technique also used for refining pixelwise trajectories for this study. A final observation made in relation to the comparing the two techniques is the negligible differences in results between them, which can be attributed to conducting this study in healthy young subjects whose ventricular shape and pattern fall within a predefined range.…”

Fully automated and comprehensive MRI-based left-ventricular contractility analysis in post-chemotherapy breast cancer patients

“…Computations of LVCQs were conducted using the contractility analysis tool created for the above methodology from data acquired via the MRI sequence of Displacement Encoding with Stimulated Echoes (DENSE). [24][25][26][27] 3D LV strains were analyzed with the strain analysis component of the tool, following which estimates of both LVCQ and 3D strains were compared to age-matched healthy subjects.…”