Effect of Temporal and Spatial Smoothing on Speckle-Tracking-Derived Strain in Neonates.
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ABSTRACT:
SUBMITTER: Khan U
PROVIDER: S-EPMC8110490 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Our objectives are to compare speckle-tracking peak global longitudinal (pGLS) and regional strain values in neonates with coarctation of aorta (CoA) and control groups. Echocardiographic parameters measured by speckle-tracking were studied in a retrospective single-center study. A comparison of pGLS and segmental deformation between neonates with CoA and control group was performed using a three-way mixed ANOVA model. There was a significant difference in the means of segmental strain values between CoA and control group at the apical (p = 0.018) and basal segments (p = 0.031) of the interventricular septum and at the apical segment (p = 0.026) of the left ventricle (LV). After correcting for multiple comparisons, the results had a tendency toward statistical significance (adjusted-p < 0.10). There was significant difference in the mean values of pGLS [F(1, 39) = 7.61, p = 0.009, adjusted p = 0.018] between the studied groups. The results of ROC analysis showed that a cut-off value of -16.60% for pGLS provided an estimated sensitivity of 92.31% (95% CI: [63.97, 99.81]) and 71.43% specificity (95% CI: [51.33, 86.78]) for the diagnosis of CoA in neonates (AUC = 0.794, 95% CI: [0.66, 0.93]). pGLS can be regarded as a feasible and reproducible parameter reflecting LV dysfunction in newborns with CoA when compared to newborns with a false-positive diagnosis.
| S-EPMC8509133 | biostudies-literature
Project description:BACKGROUND:Increased arterial stiffness has been shown to be associated with aging and cardiovascular risk factors. Speckle-tracking algorithms are being used to measure myocardial strain. The aims of this study were to evaluate whether speckle-tracking could be used to measure carotid arterial strain (CAS) reproducibly in healthy volunteers and to determine if CAS was lesser in individuals with diabetes. METHODS:Bilateral electrocardiographically gated ultrasound scans of the distal common carotid arteries (three cardiac cycles; 14-MHz linear probe; mean frame rate, 78.7 ± 8.9 frames/sec) were performed twice (2-4 days apart) on 10 healthy volunteers to test repeatability. Differences in CAS between healthy subjects (n = 20) and patients with diabetes (n = 21) were examined. Peak CAS was measured in each of six equal segments, and averages of all segments (i.e., the global average), of the three segments nearest the probe, and of the three segments farthest from the probe (i.e., the far wall average) were obtained. RESULTS:Global CAS (intraclass correlation coefficient = 0.40) and far wall average (intraclass correlation coefficient = 0.63) had the greatest test-retest reliability. Global and far wall averaged CAS values were lower in patients with diabetes (4.29% [SE, 0.27%] and 4.30% [SE, 0.44%], respectively) than in controls (5.48% [SE, 0.29%], P = .001, and 5.58% [SE, 0.44%], P = .003, respectively). This difference persisted after adjustment for age, gender, race, and hemodynamic parameters. CONCLUSIONS:Speckle-tracking to measure CAS is feasible and modestly reliable. Patients with diabetes had lower CAS obtained with speckle-tracking compared with healthy controls.
| S-EPMC3200442 | biostudies-literature
Project description:In cancer research, population-based survival analysis has played an important role. In this article, we conduct survival analysis on patients with brain tumors using the SEER (Surveillance, Epidemiology, and End Results) database from the NCI (National Cancer Institute). It has been recognized that cancer survival models have spatial and temporal variations which are caused by multiple factors, but such variations are usually not "abrupt" (that is, they should be smooth). As such, spatially and temporally pooling all data and analyzing each spatial/temporal point separately are either inappropriate or ineffective. In this article, we develop and implement a spatial- and temporal-smoothing technique, which can effectively accommodate spatial/temporal variations and realize information borrowing across spatial/temporal points. Simulation demonstrates effectiveness of the proposed approach in improving estimation. Data on a total of 123,571 patients with brain tumors diagnosed between 1911 and 2010 from 16 SEER sites is analyzed. Findings different from separate estimation and simple pooling are made. Overall, this study may provide a practically useful way for modeling the survival of brain tumor (and other cancers) using population data.
| S-EPMC6895900 | biostudies-literature
Project description:RationaleHigh-sensitivity in vivo phenotyping of cardiac function is essential for evaluating genes of interest and novel therapies in small animal models of cardiovascular disease. Transthoracic echocardiography is the principal method currently used for assessing cardiac structure and function; however, standard echocardiographic techniques are relatively insensitive to early or subtle changes in cardiac performance, particularly in mice.ObjectiveTo develop and validate an echocardiographic strain imaging methodology for sensitive and rapid cardiac phenotyping in small animal models.Methods and resultsHerein, we describe a modified echocardiographic technique that uses speckle-tracking based strain analysis for the noninvasive evaluation of cardiac performance in adult mice. This method is found to be rapid, reproducible, and highly sensitive in assessing both regional and global left ventricular (LV) function. Compared with conventional echocardiographic measures of LV structure and function, peak longitudinal strain and strain rate were able to detect changes in adult mouse hearts at an earlier time point following myocardial infarction and predicted the later development of adverse LV remodeling. Moreover, speckle-tracking based strain analysis was able to clearly identify subtle improvement in LV function that occurred early in response to standard post-myocardial infarction cardiac therapy.ConclusionsOur results highlight the utility of speckle-tracking based strain imaging for detecting discrete functional alterations in mouse models of cardiovascular disease in an efficient and comprehensive manner. Echocardiography speckle-tracking based strain analysis represents a method for relatively high-throughput and sensitive cardiac phenotyping, particularly in evaluating emerging cardiac agents and therapies in mice.
| S-EPMC3376717 | biostudies-literature
Project description:This study developed an improved motion estimation algorithm for ultrasonic strain imaging that employs a dynamic programming technique. In this article, we model the motion estimation task as an optimization problem. Since tissue motion under external mechanical stimuli often should be reasonably continuous, a set of cost functions combining correlation and various levels of motion continuity constraint were used to regularize the motion estimation. To solve the optimization problem with a reasonable computational load, a dynamic programming technique that does not require iterations was used to obtain displacement vectors in integer precision. Then, a subsample estimation algorithm was used to calculate local displacements in fractional precision. Two implementation schemes were investigated with in vivo ultrasound echo data sets. We found that the proposed algorithm provides more accurate displacement estimates than our previous algorithm for in vivo clinical data. In particular, the new algorithm is capable of tracking motion in more complex anatomy and increases strain image consistency in a sequence of images. Preliminary results also suggest that a significantly longer sequence of high contrast strain images could be obtained with the new algorithm compared with the previous algorithm. The new algorithm can also tolerate larger motion discontinuities (e.g., cavity in an anthropomorphic uterine phantom).
| S-EPMC2843521 | biostudies-literature
Project description:Spatial smoothing is a widely used preprocessing step in functional magnetic resonance imaging (fMRI) data analysis. In this work, we report on the spatial smoothing effect on task-evoked fMRI brain functional mapping and functional connectivity. Initially, we decomposed the task fMRI data into a collection of components or networks by independent component analysis (ICA). The designed task paradigm helps identify task-modulated ICA components (highly correlated with the task stimuli). For the ICA-extracted primary task component, we then measured the task activation volume at the task response foci. We used the task timecourse (designed) as a reference to order the ICA components according to the task correlations of the ICA timecourses. With the re-ordered ICA components, we calculated the inter-component function connectivity (FC) matrix (correlations among the ICA timecourses). By repeating the spatial smoothing of fMRI data with a Gaussian smoothing kernel with a full width at half maximum (FWHM) of {1, 3, 6, 9, 12, 15, 20, 25, 30, 35} mm, we measured the spatial smoothing effects. Our results show spatial smoothing reveals the following effects: (1) It decreases the task extraction performance of single-subject ICA more than that of multi-subject ICA; (2) It increases the task volume of multi-subject ICA more than that of single-subject ICA; (3) It strengthens the functional connectivity of single-subject ICA more than that of multi-subject ICA; and (4) It impacts the positive-negative imbalance of single-subject ICA more than that of multi-subject ICA. Our experimental results suggest a 2~3 voxel FWHM spatial smoothing for single-subject ICA in achieving an optimal balance of functional connectivity, and a wide range (2~5 voxels) of FWHM for multi-subject ICA.
| S-EPMC5801305 | biostudies-literature
Project description: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 (SRSsept) was poor (CMR-FT: 0.41, STE: 0.30). Internal stretch factor of septal and lateral wall (ISFsep-lat) showed fair ICC values (CMR-FT: 0.53, STE: 0.46), while the ICC of the total LV (ISFLV) 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.
| S-EPMC5847211 | biostudies-literature
Project description:Ultrashort light pulses induce rapid deformations of crystalline lattices. In ferroelectrics, lattice deformations couple directly to the polarization, which opens the perspective to modulate the electric polarization on an ultrafast time scale. Here, we report on the temporal and spatial tracking of strain and polar modulation in a single-domain BiFeO3 thin film by ultrashort light pulses. To map the light-induced deformation of the BiFeO3 unit cell, we perform time-resolved optical reflectivity and time-resolved x-ray diffraction. We show that an optical femtosecond laser pulse generates not only longitudinal but also shear strains. The longitudinal strain peaks at a large amplitude of 0.6%. The access of both the longitudinal and shear strains enables to quantitatively reconstruct the ultrafast deformation of the unit cell and to infer the corresponding reorientation of the ferroelectric polarization direction in space and time. Our findings open new perspectives for ultrafast manipulation of strain-coupled ferroic orders.
| S-EPMC10651133 | biostudies-literature
Project description:Right ventricular (RV) strain measurements from ultrasound via speckle-tracking techniques are being used more frequently as a non-invasive diagnostic tool for a variety of cardiopulmonary pathologies. However, despite the clinical utility of ultrasound RV strain measurements, quantification of RV strain in rodents remains difficult owing to unique image artifacts and non-standardized methodologies. We demonstrate here a simple approach for measuring RV strain in both mice and rats using high-frequency ultrasound and automated speckle tracking. Our results show estimated peak RV free-wall longitudinal strain values (mean ± standard error of the mean) in mice (n = 15) and rats (n = 5) of, respectively, -10.38% ± 0.4% and -4.85% ± 0.42%. We further estimated the 2-D Green-Lagrange strain within the RV free wall, with longitudinal components estimated at -5.7% ± 0.48% in mice and -2.1% ± 0.28% in rats. These methods and data may provide a foundation for future work aimed at evaluating murine RV strain levels in different disease models.
| S-EPMC8488001 | biostudies-literature
Project description:BackgroundNewer 2D strain software has a potential to assess layer-specific strain. However, normal reference values for layer-specific strain have not been established. We aimed to establish the normal ranges of layer-specific longitudinal and circumferential strain (endocardial global longitudinal strain (GLS), transmural GLS, epicardial GLS, endocardial global circumferential strain (GCS), transmural GCS, and epicardial GCS).Methods and resultsWe retrospectively analyzed longitudinal and circumferential strain parameters in 235 healthy subjects, with use of layer-specific 2D speckle tracking software (GE). The endocardial strain/epicardial strain (Endo/Epi) ratio was also measured to assess the strain gradient across the myocardium. The endocardial, transmural, and epicardial GLS values and the Endo/Epi ratio in the normal subjects were -23.1±2.3, -20.0±2.0, -17.6±1.9, and 1.31±0.07, respectively. The corresponding values of GCS were -28.5±3.0, -20.8±2.3, -15.3±2.0, and 1.88±0.17, respectively. The layer-specific global strain parameters exhibited no age dependency but did exhibit gender dependency except for endocardial GCS. A subgroup analysis revealed that basal and middle levels of endocardial LS was decreased in the middle and elderly aged group. However, apical endocardial LS was preserved even in the elderly subjects.ConclusionsWe proposed normal reference values for layer-specific strain based on both age and gender. This detailed strain analysis provides layer-oriented information with the potential to characterize abnormal findings in various cardiovascular diseases.
| S-EPMC5491258 | biostudies-literature