Evaluation of left ventricular function with cardiac magnetic resonance imaging and echocardiography after administration of dobutamine and esmolol in healthy beagle dogs

Figures

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  Fig. 1.. Image planning to acquire a short-axis view, long-axis 3-chamber view (LVOT), and long-axis 4-chamber view in cardiac MRI. The left ventricle is shown on scout images of sagittal (A) and transverse (B) view. The yellow lines serve as a guide to obtain short-axis view (C, D). Check image of the short-axis view, including papillary muscles (D, arrows). In this short-axis view of papillary muscle level (E), left ventricular outflow tract (LVOT) view (F) is set along the yellow line. The imaging plane of long-axis 4-chamber view (I) is made along the yellow line in the short-axis view of papillary muscle level (G) or set perpendicular to the mitral valve in LVOT view (H).

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  Fig. 2.. Image planning to acquire short-axis view of whole left ventricle for measurement of cardiac output in cardiac MRI. In the long-axis 3-chamber view (LVOT) or 4-chamber view, short-axis images of left ventricle (A to G) are obtained along the yellow lines from mitral valve level to apex level, perpendicularly to interventricular septum. Using semi-automating software, the left ventricular endocardial area (A to G, green line) was traced and each area of the two-dimensional plane was added on both end systolic and end diastolic cycles. End diastolic volume (EDV) and end systolic volume (ESD) were calculated by multiplication of slice thickness (8 mm). The cardiac output was induced by using differences between EDV and ESV.

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  Fig. 3.. Graphical presentation about stroke volume at cardiac MRI (A). Teichholz (B) and Simpson (C) method, and about ejection fraction at cardiac MRI (D), Teichholz (E) and Simpson (F) method with median and range. *P<0.002. SV, stroke volume; EF, ejection fraction; MR, cardiac MRI; Echo(Tei), echocardiography using Teichholz method; Echo(Sim), echocardiography using Simpson method.

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  Fig. 4.. Graphical presentation about comparison of stroke volume between cardiac MRI and echocardiography with Teichholz (A to G) and Simpson (H to N) method in Bland-Altman plots. Continuous lines depict the mean of differences; dashed lines denote limits of agreement (mean ± 1.96 times of standard deviation). E(H), esmolol high dose (500 µg/kg/min); E(M), esmolol middle dose (200 µg/kg/min); E(L), esmolol low dose (100 µg/kg/min); N, normal (no administration of drugs); D(L), dobutamine low dose (10 µg/kg/min); D(M), dobutamine middle dose (20 µg/kg/min); D(H), dobutamine high dose (50 µg/kg/min); MR, cardiac MRI; Echo(Tei), echocardiography using Teichholz method; Echo(Sim), echocardiography using Simpson method.

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  Fig. 5.. Graphical presentation about comparison of ejection fraction between cardiac MRI and echocardiography with Teichholz (A to G) and Simpson (H to N) method in Bland-Altman plots. Continuous lines depict the mean of differences; dashed lines denote limits of agreement (mean ± 1.96 times of standard deviation). E(H), esmolol high dose (500 µg/kg/min); E(M), esmolol middle dose (200 µg/kg/min); E(L), esmolol low dose (100 µg/kg/min); N, normal (no administration of drugs); D(L), dobutamine low dose (10 µg/kg/min); D(M), dobutamine middle dose (20 µg/kg/min); D(H), dobutamine high dose (50 µg/kg/min); MR, cardiac MRI; Echo(Tei), echocardiography using Teichholz method; Echo(Sim), echocardiography using Simpson method.

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  Fig. 6.. Graphical presentation about comparison of stroke volume between cardiac MRI and echocardiography with Teichholz (A) and Simpson (B) method, and about comparison of ejection fraction between cardiac MRI and echocardiography with Teichholz (C) and Simpson (D) method in Bland-Altman plots. Continuous lines depict the mean of differences; dashed lines denote limits of agreement (mean ± 1.96 times of standard deviation). MR, cardiac MRI; Echo(Tei), echocardiography using Teichholz method; Echo(Sim), echocardiography using Simpson method.