Objective: To understand the effect of dobutamine on the integrated backscatter of myocardium. Methods: Nineteen open-chest dogs were detected by HP Sonos 5500 with S8 transducer, and the WT, AIBS and CVIB were measured before and after the dobutamine stress. Results: During the dobutamine stress, following the increase of WT, the transmural, subepicardial and subendocardial CVIB all increased. And the increase of subepicardial CVIB was greater than that of subendocardial CVIB, leading to the decrease of TGI. But the AIBS didn't change significantly in the whole process. Conclusion: Dobutamine can enhance myocardium CVIB but has no obvious infleunce on AIBS.

Objective: To understand the effect of dobutamine on the integrated backscatter of myocardium. Methods: Nineteen open chest dogs were detected by HP Sonos 5500 with S8 transducer, and the WT, AIBS and CVIB were measured before and after the dobutamine stress. Results: During the dobutamine stress, following the increase of WT, the transmural, subepicardial and subendocardial CVIB all increased. And the increase of subepicardial CVIB was greater than that of subendocardial CVIB, leading to the decrease of TGI. But the AIBS didn't change significantly in the whole process. Conclusion: Dobutamine can enhance myocardium CVIB but has no obvious infleunce on AIBS. [