Automated Analysis of Myocardial Deformation at Dobutamine Stress EchocardiographyAn Angiographic Validation
Charlotte Bjork Ingul, MD*, ,
Asbjorn Stoylen, MD, PhD*,1,
Stig A. Slordahl, MD, PhD*,
Rune Wiseth, MD, PhD*,
Malcolm Burgess, MD and
Thomas H. Marwick, MD, PhD,*
* Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
University of Queensland, Brisbane, Australia.
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Figure 1 Strain and Strain Rate Profiles With Automated Velocity and Segment Length Methods
Strain rate and strain estimated with the 2 different methods (red curve = segment length method, blue curve = velocity gradient method). Strain rate traces are shown in the left image, and strain traces are shown in the right image. The traces are from a patient at peak dose showing ischemia in apical septum with low strain rate/strain values. The traces in the lowest images show postsystolic strain. Note the differences in the curves, the red trace has in general reduced value and a different shape compared with the blue trace. The red trace is smoother, probably because of lower temporal resolution. AVC = aortic valve closure.
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Figure 2 Receiver-Operating Characteristic Curves and Optimal Cutoff Points for Various Deformation Indexes
The receiver-operating characteristic curves and area under the curve (AUC) at peak dobutamine stress echocardiography for peak systolic strain rate, post-systolic strain index (PSI), end systolic strain, delta strain, delta strain rate, and time to peak systolic strain rate for velocity gradient and segment length methods.
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Figure 3 Accuracy of Stress Deformation Parameters for Diagnosis of CAD
The sensitivity, specificity, and accuracy of the 3 most important strain rate imaging parameters during peak stress are shown in the 2 figures for the patients with coronary angiography. Values for the segment length method and the velocity gradient method are given in the 2 figures. The sensitivity, specificity, and accuracy for the optimal cutoffs values are based on receiver-operating characteristics curves in group A and are evaluated here in group B. CAD = coronary artery disease; PSI = postsystolic strain index; Ses = end-systolic strain; SRs = peak systolic strain rate.
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Figure 4 Comparison of Accuracy of SRs and Strain With WMS
Wall motion score (WMS) and peak systolic strain rate are compared for velocity gradient and segment length methods in 136 patients with an angiogram. Sensitivity (Sens), specificity (Spec), and accuracy (Acc) are compared as well as the sensitivity for the 3 main coronary arteries in single-vessel disease (n = 35): left main artery (n = 16), circumflex artery (n = 9), and right coronary artery (n = 10). SRs = peak systolic strain rate.
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