Shear-wave Amplitudes Measured with Cardiac MR Elastography for Diagnosis of Diastolic Dysfunction

Elgeti, Thomas; Knebel, Fabian; Hättasch, Robert; Hamm, Bernd; Braun, Jürgen; Sack, Ingolf

doi:10.1148/radiol.13131605

Cited by 37 publications

(42 citation statements)

References 29 publications

(31 reference statements)

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“…We believe this is because the systolic stiffness increases more than the diastolic stiffness, which is due to the heart having to work harder because of increase in afterload during systole associated with changes in aortic compliance with increasing age(35). Furthermore, Elgeti, et al (21) showed no correlation of CMRE-derived displacements (i.e. stiffness) to age which agrees with our results.…”

Section: Discussionsupporting

confidence: 92%

Measuring age‐dependent myocardial stiffness across the cardiac cycle using MR elastography: A reproducibility study

Wassenaar

Eleswarpu

Schroeder

et al. 2015

Magnetic Resonance in Med

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Purpose To assess reproducibility in measuring left ventricular (LV) myocardial stiffness in volunteers throughout the cardiac cycle using magnetic resonance elastography (MRE) and to determine its correlation with age. Methods Cardiac MRE (CMRE) was performed on 29 normal volunteers, with ages ranging from 21 to 73 years. For assessing reproducibility of CMRE-derived stiffness measurements, scans were repeated per volunteer. Wave images were acquired throughout the LV myocardium, and were analyzed to obtain mean stiffness during the cardiac cycle. CMRE-derived stiffness values were correlated to age. Results Concordance correlation coefficient revealed good inter-scan agreement with rc of 0.77, with p-value<0.0001. Significantly higher myocardial stiffness was observed during end-systole (ES) compared to end-diastole (ED) across all subjects. Additionally, increased deviation between ES and ED stiffness was observed with increased age. Conclusion CMRE-derived stiffness is reproducible, with myocardial stiffness changing cyclically across the cardiac cycle. Stiffness is significantly higher during ES compared to ED. With age, ES myocardial stiffness increases more than ED, giving rise to an increased deviation between the two.

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Section: Discussionsupporting

confidence: 92%

Measuring age‐dependent myocardial stiffness across the cardiac cycle using MR elastography: A reproducibility study

Wassenaar

Eleswarpu

Schroeder

et al. 2015

Magnetic Resonance in Med

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“…Other techniques are now under development to estimate myocardial shear elasticity/viscoelasticity [2, 5, 13, 19, 29, 38, 42, 43]; however, transthoracic measurements are still technically challenging and require special equipment or are based on magnetic resonance imaging, which has limited availability. Conversely, TDI is now available on all commercial systems for cardiac imaging.…”

Section: Discussionmentioning

confidence: 99%

Wave propagation of myocardial stretch: correlation with myocardial stiffness

2014

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The mechanism of flow propagation during diastole in the left ventricle (LV) has been well described. Little is known about the associated waves propagating along the heart wall s. These waves may have a mechanism similar to pulse wave propagation in arteries. The major goal of the study was to evaluate the effect of myocardial stiffness and preload on this wave transmission. Methods Longitudinal late diastolic deformation and wave speed (Vp) of myocardial stretch in the anterior LV wall were measured using sonomicrometry in sixteen pigs. Animals with normal and altered myocardial stiffness (acute myocardial infarction) were studied with and without preload alterations. Elastic modulus estimated from Vp (EVP; Moens-Korteweg equation) was compared to incremental elastic modulus obtained from exponential end -diastolic stress-strain relation (ESS). Myocardial distensibility and α-and β-coefficients of stress-strain relations were calculated. Results Vp was higher at reperfusion compared to baseline (2.6±1.3 m/s vs. 1.3±0.4 m/s; p=0.005) and best correlated with ESS (r 2=0.80, p<0.0001), β-coefficient (r2=0.78, p<0.0001), distensibility (r2=0.47, p=0.005), and wall thickness/diameter ratio (r2=0.42, p=0.009). Elastic moduli (EVP and ESS) were strongly correlated (r2=0.83, p<0.0001). Increasing preload increased Vp and EVP and decreased distensibility. At multivariate analysis, ESS, wall thickness, and end-diastolic and systolic LV pressures were independent predictors of Vp (r2model=0.83, p<0.0001). Conclusions The main determinants of wave propagation of longitudinal myocardial stretch were myocardial stiffness and LV geometry and pressure. This local wave speed could potentially be measured noninvasively by echocardiography.

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“…Magnetic resonance elastography (MRE) has been used to measure shear waves from an external vibration source to evaluate wave propagation in the myocardial wall (Kolipaka et al ., 2010; Kolipaka et al ., 2011; Sack et al ., 2009; Elgeti et al ., 2009; Tzschätzsch et al ., 2012; Elgeti et al ., 2012; Elgeti et al ., 2014). The frequencies used for generating the shear waves for these cardiac applications using MRE typically range from 24-200 Hz.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the effects of myocardial anisotropy for shear wave elastography using impulsive force and harmonic vibration

et al. 2015

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The myocardium is known to be an anisotropic medium where the muscle fiber orientation changes through the thickness of the wall. Shear wave elastography methods use propagating waves which are measured by ultrasound or magnetic resonance imaging (MRI) techniques to characterize the mechanical properties of various tissues. Ultrasound- or MR-based methods have been used and the excitation frequency ranges for these various methods cover a large range from 24-500 Hz. Some of the ultrasound-based methods have been shown to be able to estimate the fiber direction. We constructed a model with layers of elastic, transversely isotropic materials that were oriented at different angles to simulate the heart wall in systole and diastole. We investigated the effect of frequency on the wave propagation and the estimation of fiber direction and wave speeds in the different layers of the assembled models. We found that waves propagating at low frequencies such as 30 or 50 Hz showed low sensitivity to the fiber direction but also had substantial bias in estimating the wave speeds in the layers. Using waves with higher frequency content (> 200 Hz) allowed for more accurate fiber direction and wave speed estimation. These results have particular relevance for MR- and ultrasound-based elastography applications in the heart.

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Shear-wave Amplitudes Measured with Cardiac MR Elastography for Diagnosis of Diastolic Dysfunction

Abstract: LV SWA measured with cardiac MR elastography provides image contrast sensitive to myocardial relaxation abnormalities and shows significantly lower values in patients with diastolic dysfunction.

Cited by 37 publications

References 29 publications

Measuring age‐dependent myocardial stiffness across the cardiac cycle using MR elastography: A reproducibility study

Measuring age‐dependent myocardial stiffness across the cardiac cycle using MR elastography: A reproducibility study

Wave propagation of myocardial stretch: correlation with myocardial stiffness

Investigation of the effects of myocardial anisotropy for shear wave elastography using impulsive force and harmonic vibration

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