Examination of myocardial ultrasonic backscatter parameters and its value in patients with super-acute phase of myocardial infarction

Abstract

Objective To study the changes and their value of ultrasonic myocardial integrated backscatter （IBS）in normal control and patients with super-acute phase of myocardial infarction. Methods There were 38 cases of acute myocardial infarction（AMI）patients in the super-acute phase（time 〈 2 h infarction）and the acute phase（infarction time 〉 2 h,typical ECG changes）for myocardial ultrasonic backscatter parameters detection,an additional 25 cases as healthy control group. The myocardial infarction region and non-infracted myocardial tissue region average duration of cardiac cycle of integrated backscatter（IBS）were measured,and IBS adjusted value （IBS%）was calculated as the ratio of myocardial IBS to the pericardium,the difference of IBS at end-diastolic and late systolic was used as cyclic variation of IBS（CVIB）. The ratio of IBS to pericardial CVIB was used as its adjusted value（CVIB%）. Over the same period for the electrocardiogram,myocardial enzymes and cardiac troponin I were measured. Results When ECG was not typically changed in patients with super-acute phase AMI,the IBS values significantly increased in the myocardial infarction region than the normal control group （43. 7 ± 10. 8）dB vs.（22. 6 ± 4. 6）dB,P 〈0.01）,and CVIB was significantly lower than that in the normal control group（10. 2 ±2. 6）dB vs.（13. 2 ± 3.8）dB,P 〈 0.01]. The IBS in the acute phase in patients was significantly higher than that in the normal control group and those non-infarcted areas,and CVIB was significantly lower than that in the normal control group and those in the non-infarcted areas. The changes were consistent with the ECG changes. Conclusions Ultrasonic backscatter parameters might be helpful for diagnosis of hyperacute period of AMI,and the determination of the scope and extent of AMI. Key words: Acute myocardial infarction Echocardiography