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Figure 4 An example of the early appearance of an apical perfusion defect (arrows) in the apical four-chamber view after intravenous (IV) Optison administration during low dose dobutamine echocardiography. Rest contrast enhancement is shown in the right top panel, low dose dobutamine images in the left bottom panel and peak images in the right bottom panel. Both wall motion and contrast enhancement were abnormal in the apex at peak dobutamine stress (right bottom panel). This patient had significant left anterior descending coronary artery (LAD) stenoses on quantitative angiography (QA). The left upper panel is before ultrasound contrast under baseline conditions.