Comparative assessment of coronary physiology using transthoracic pulsed-wave Doppler and myocardial contrast echocardiography in rats

Figures

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  Fig. 1. Schematic experimental setup with a rat in the supine position. Coronary circulation was studied by pulsed-wave Doppler of the left coronary artery and by myocardial contrast echocardiography. Measurements were performed under three conditions: baseline, adenosine, and dobutamine (created with Biorender.com)

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  Fig. 2. Representative B-mode and colour Doppler images acquired in a parasternal long axis (PLAX). a B-mode PLAX of the left ventricle. These images were used for volumetric and perfusion measurements. AA Ascending aorta, LA Left atrium, LV Left ventricle, LVASW Left ventricular anteroseptal wall, LVILW Left ventricular inferolateral wall, *aortic valve, # mitral valve. b Exemplary colour Doppler image of the proximal left coronary artery, which was assessed by pulsed-wave Doppler in the following step. *Proximal left coronary artery

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  Fig. 3. Representative pulsed-wave Doppler coronary flow patterns. The signals are shown with the corresponding electrodardiographic signal during baseline conditions (a), infusion of 140 μg/kg body weight/min adenosine (b), and infusion of 10 μg/kg body weight/min dobutamine (c)

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  Fig. 4. Representative time course of contrast activity in the lumen of the left ventricle. Shown are systolic gated modified parasternal long axis images that were acquired during nonlinear contrast imaging at the time of contrast agent arrival, i.e., 0 s (a), 1 s (b), and 10 s (c) after contrast agent arrival

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  Fig. 5. Illustration of the myocardial perfusion assessment in Vevo CQ. a Placement of the ventricular region of interest (ROI, pink) and the myocardial ROI (yellow). b Parametric colour-coded image showing the peak enhancement. c Time-intensity curve of the ventricular (pink) and myocardial (yellow) ROIs on a logarithmic scale. The bold line represents the fitted perfusion model, while the thin line represents the measured data points

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  Fig. 6. a Transthoracic echocardiography parameters from eight rats under baseline conditions and stimulation with adenosine and dobutamine: ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV). b Visualisation of the following pulsed wave Doppler-derived blood flow parameters in eight rats: diastolic peak velocity (DPV), velocity time integral (VTI), and coronary flow velocity reserve (CFVR). c Graphs showing the effect of adenosine and dobutamine on myocardial perfusion measured by myocardial contrast echocardiography (MCE) in eight rats using the following parameters: normalised peak enhancement (normalised PE), normalised wash-in rate (normalised WIR), and normalised area under the curve (normalised AUC). * p < 0.05; ** p < 0.01; ***p <0.001. Values are shown as the mean ± standard deviation

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  Fig. 7. Correlation plots of pulsed-wave Doppler (PWD) and myocardial contrast echocardiography (MCE) parameters. a The diastolic peak velocity (DPV) derived from PWD showed a positive correlation with the normalised area under the curve (normalised AUC) derived from MCE (r = 0.59, p = 0.002). b The PWD-derived velocity time integral (VTI) showed a positive correlation with the normalised AUC (r = 0.54, p = 0.007) measured by MCE. Dotted lines represent 95% confidence interval