Variability of longitudinal strain measurements: levelling the playing field

2018 ◽  
Vol 74 (3) ◽  
pp. 188-197 ◽  
Author(s):  
Oana Mirea ◽  
Oana Maria Corîci ◽  
Mihaela Berceanu ◽  
Ionuţ Donoiu ◽  
Constantin Militaru ◽  
...  
2017 ◽  
Vol 38 (suppl_1) ◽  
Author(s):  
S. Unlu ◽  
O. Mirea ◽  
J. Duchenne ◽  
E.D. Pagourelias ◽  
J.U. Voigt

2007 ◽  
Vol 539-543 ◽  
pp. 3795-3800 ◽  
Author(s):  
W. Woo ◽  
Hahn Choo ◽  
Donald W. Brown ◽  
Bjørn Clausen ◽  
Zhi Li Feng ◽  
...  

Residual strain profiles in friction-stir processed (FSP) AZ31B magnesium-alloy plates were measured using neutron diffraction. Two different specimens were prepared to investigate the influences of the tool shoulder and the tool pin on the residual-strain profiles: (Case 1) a plate processed with both the stirring pin and tool shoulder, i.e., a regular FSP plate subjected to both the plastic deformation and frictional heating, and (Case 2) a plate processed only with the tool shoulder, i.e., subjected mainly to the frictional heating. The results show that the strain profiles of both cases are qualitatively quite similar. The longitudinal strain is mainly tensile with its maximum near the bead of the FSP plate. On the other hand, the transverse and normal strains are mildly compressive in both Cases 1 and 2.


2015 ◽  
Vol 28 (10) ◽  
pp. 1171-1181.e2 ◽  
Author(s):  
Konstantinos E. Farsalinos ◽  
Ana M. Daraban ◽  
Serkan Ünlü ◽  
James D. Thomas ◽  
Luigi P. Badano ◽  
...  

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
N Bekki ◽  
H Hayama ◽  
R Nagai ◽  
W Miyake ◽  
J Yamamoto ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial (LA) function is impaired in heart failure with preserved ejection fraction (HFpEF). However, the association between LA longitudinal strain and heart failure (HF) events in patients with HFpEF is still unknown. We evaluated whether LA strain measurements would be useful to predict hospitalizations for worsening HF in this study. Methods This study included 121 patients (Male 73, Female 48) with HFpEF who had echocardiogram at our institute (Age = 76 ± 14y, Left ventricular ejection fraction; LVEF = 63 ± 8%). Patients with atrial fibrillation were excluded. LA longitudinal strain was measured by speckle-tracking echocardiography, using TOMTEC imaging system. The endpoints were hospitalizations for worsening HF. Results During follow-up period of 319 ± 269 days, 33 patients (27%) experienced hospitalizations for worsening HF. LA strain was markedly lower in patients with HF events at 11.3 ± 5.6, whereas LA strain was higher at 20.3 ± 10.1 in patients without HF events. Kaplan-Meier analysis demonstrated a significant separation of survival curves stratified by median value of LA strain (Figure). Conclusions LA dysfunction in HFpEF is associated with a higher risk of HF hospitalization, and LA strain measurements would be useful to predict HF events. Abstract Figure


2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
S Unlu ◽  
O Mirea ◽  
S Bezy ◽  
J Duchenne ◽  
ED Pagourelias ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: None. Background Vendors use proprietary speckle tracking software algorithms for echocardiographic strain measurements, which results in high inter-vendor variability. Little is known about potential advantages or disadvantages of using vendor-independent software in clinical practice. Purpose We therefore investigated the reproducibility, accuracy, and ability to identify scar of strain measurements on images from different vendors by using a vendor-independent software. Methods A vendor-independent software (TomTec Image Arena) was used to analyze datasets of 63 patients which were obtained on four ultrasound machines from different vendors (GE, Philips, Siemens, Toshiba). We measured the tracking feasibility, inter-vendor bias, the relative and absolute test-re-test variability of strain measurements and their ability to detect scar. Cardiac magnetic resonance delayed enhancement images were used as the reference standard of scar definition. Results Tracking feasibility differed depending on the image source (p < 0.05). Variability of global longitudinal strain (GLS) (Figure 1A) was similar (ANOVA p = 0.124) among the images of different vendors whereas variability of segmental longitudinal strain (SLS) (Figure 1B) showed modest difference (ANOVA- peak systolic strain (PS); p = 0.077, end-systolic strain (ES); p = 0.171, post-systolic strain (PSS); p = 0.020). Relative test-re-test variability of GLS showed no differences (ANOVA p = 0.360). Absolute test-re-test errors of SLS measurements showed modest differences among images of different vendors (ANOVA- PS; p = 0.018, ES; p = 0.001, PSS; p = 0.090). No relevant difference in scar detection capability was observed (Figure 1C). Conclusions Vendor independent software leads to low bias among strain measurements on images from different vendors. Likewise, measurement variability and the ability to identify scar becomes similar. Our findings suggest that a vendor independent speckle tracking software could help to overcome inter-vendor bias. To which extend such measurements would be more accurate compared to vendor specific software remains to be determined. Abstract Figure 1


1985 ◽  
Vol 22 (4) ◽  
pp. 506-513 ◽  
Author(s):  
W. M. Schwerdtner

Simple two-dimensional techniques are used to make an estimate of the total shortening across a narrow greenstone belt in northwestern Ontario. The techniques are based on the basic principle of restoring the predeformational geometry of a horizontal traverse across the belt. Depending on the technique used this traverse is a string of line elements or a chain of finite elements. The strain ratios available for the restoration are minimal values and need to be increased significantly to obtain realistic results. Depending on the strain values selected for the restoration, amounts of horizontal shortening range from 17 to 49%. The actual amount remains unknown, but is thought to be < 50%.In view of the apparent variation in longitudinal strain along the greenstone belt, a three-dimensional treatment seems to be necessary. This would require that strain measurements be taken systematically throughout, rather than along a single traverse across, a greenstone belt segment.


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