Ultrasound Shear Wave Elasticity Imaging Quantifies Coronary Perfusion Pressure Effect on Cardiac Compliance

Vejdani‐Jahromi, Maryam; Nagle, Matt; Trahey, Gregg E.; Wolf, Patrick D.

doi:10.1109/tmi.2014.2360835

Cited by 30 publications

(31 citation statements)

References 36 publications

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“…This effect was characterized in a previous publication from our group. Consistent with the literature, the 95% CI for the garden hose effect on stiffness was found to be 0.04 kPa/mmHg with R 2 = 0.83 19,24 . This slope is significantly lower than that of the Gregg effect relationship found in this study (95% CI is 0.20–0.34 kPa/mmHg).…”

Section: Discussionsupporting

confidence: 87%

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Quantifying Myocardial Contractility Changes Using Ultrasound-Based Shear Wave Elastography

Vejdani‐Jahromi

Freedman

Nagle

et al. 2017

Journal of the American Society of Echocardiography

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BACKGROUND Myocardial contractility, a significant determinant of cardiac function, is valuable for diagnosis and evaluation of treatment in cardiovascular disorders including heart failure. Shear Wave Elasticity Imaging (SWEI) is a newly developed ultrasound-based elastography technique that can directly assess the stiffness of cardiac tissue. The aim of the study was to verify the ability of technique to quantify contractility changes in the myocardium. METHODS In 12 isolated rabbit hearts we made SWEI measurements of systolic stiffness at 5 different coronary perfusion pressures from 0 to 92 mmHg. The changes in coronary perfusion were used to induce acute stepwise reversible changes in cardiac contractility via the Gregg effect. The Gregg effect is the dependency of contractility on coronary perfusion. In 4 of the hearts, we repeated the measurements after delivery of Gadolinium, which is known to block the Gregg effect. RESULTS Systolic stiffness measured by SWEI changed linearly with coronary perfusion pressure with a slope of 0.27 kPa/mmHg (mean of 95% CI, R2=0.73). As expected the change in contractility due to the Gregg effect was blocked by Gadolinium with a significant reduction of the slope to 0.08 kPa/mmHg. CONCLUSION SWEI measurements of systolic stiffness provide an index of contractility in the unloaded isolated rabbit heart. While this study was done under ideal imaging conditions and with non-physiological loading conditions, it reinforces the concept that this ultrasound technique has the potential to provide a direct and noninvasive index of cardiac contractility.

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Section: Discussionsupporting

confidence: 87%

“…As the coronary perfusion is increased the cardiac stiffness increases at all phases of the cardiac cycle. This increase of stiffness in systole is called the Gregg effect and in diastole is known as the garden hose effect 19 …”

Section: Resultsmentioning

confidence: 99%

Quantifying Myocardial Contractility Changes Using Ultrasound-Based Shear Wave Elastography

Vejdani‐Jahromi

Freedman

Nagle

et al. 2017

Journal of the American Society of Echocardiography

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“…The perfusion solution and the bath were kept at 37–38°C. Additional details about the procedure and the experimental setup can be found in our previous publication [8]. …”

Section: Methodsmentioning

confidence: 99%

“…The effects are known as the ‘garden hose’ and ‘Gregg’ effects for diastole and systole respectively [7], [8]. In addition to investigating the factors affecting ARFI and SWEI, it is important to study potential functional indices of the heart that could be measured using ARFI and SWEI.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Acoustic Radiation Force-Derived Indices of Cardiac Function in the Langendorff Perfused Rabbit Heart

Vejdani‐Jahromi

Nagle

Yang

et al. 2016

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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In the past decade, there has been an increased interest in characterizing cardiac tissue mechanics utilizing newly developed ultrasound-based elastography techniques. These methods excite the tissue mechanically and track the response. Two frequently used methods, acoustic radiation force impulse and shear wave elasticity imaging (ARFI and SWEI), have been considered qualitative and quantitative techniques providing relative and absolute measures of tissue stiffness respectively. Depending on imaging conditions, it is desirable to identify indices of cardiac function that could be measured by ARFI and SWEI and to characterize the relationship between the measures. In this study, we have compared two indices (i.e. relaxation time constant used for diastolic dysfunction assessment and systolic/diastolic stiffness ratio) measured nearly simultaneously by M-mode ARFI and SWEI techniques. We additionally correlated ARFI-measured inverse displacements with SWEI measured values of the shear modulus of stiffness. For the eight animals studied, the average relaxation time constant ( ) measured by ARFI and SWEI were (69±18 ms, R2=0.96) and (65±19 ms, R2=0.99), (ARFI-SWEI inter-rater agreement = 0.90). Average systolic/diastolic stiffness ratio for ARFI, and SWEI measurements were 6.01±1.37 and 7.12±3.24 respectively (agreement=0.70). Shear modulus of stiffness (SWEI) was linearly related to inverse displacement values (ARFI) with a 95% CI for the slope of 0.010–0.011 (1/μm)/(kPa) (R2=0.73). In conclusion, the relaxation time constant and the systolic/diastolic stiffness ratio were calculated with good agreement between the ARFI and SWEI derived measurements. ARFI relative and SWEI absolute stiffness measurements were linearly related with varying slopes based on imaging conditions and subject tissue properties.

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“…A study in open chest dogs using waves generated using ARF was reported by Bouchard, et al (Bouchard et al ., 2009). Variation of shear modulus in Langendorff perfused isolated rat and rabbit hearts was also explored using ARF methods (Pernot et al ., 2011; Vejdani-Jahromi et al ., 2015). Intracardiac transducers have also been used to produce shear waves in normal pigs and pigs with infarcted regions (Hollender et al ., 2012; Hollender et al ., 2013).…”

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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Ultrasound Shear Wave Elasticity Imaging Quantifies Coronary Perfusion Pressure Effect on Cardiac Compliance

Cited by 30 publications

References 36 publications

Quantifying Myocardial Contractility Changes Using Ultrasound-Based Shear Wave Elastography

Quantifying Myocardial Contractility Changes Using Ultrasound-Based Shear Wave Elastography

A Comparison of Acoustic Radiation Force-Derived Indices of Cardiac Function in the Langendorff Perfused Rabbit Heart

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

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