Ultrasonic integrated backscatter discloses intramyocardial hemorrhage in patients with acute myocardial infarction

Background: It has been reported that intramyocardial hemorrhage (IH) can be detected by magnetic resonance imaging (MRI) and IH correlates with the poor prognosis of acute myocardial infarction (AMI). We examined whether integrated backscatter (IBS) can disclose IH in patients with AMI. We recorded IBS images in 34 patients with AMI who underwent coronary angioplasty within 12 hours of symptom onset. Methods: We measured calibrated IBS (C-IB) and cyclic variation (CV) in the center of the risk area on the third day after reperfusion. C-IB was calculated as: average IBS value of risk area - average IBS value of intraventricular blood. MRI was performed within 3 days after reperfusion. Regional wall motion score index (RWMSI) was calculated as follows: sum of scores (0 similar to 4) in risk area/number of segments of risk area. We evaluated left ventricular function using RWMSI shortly and one month after reperfusion. Results: RWMSI in the IH group (12 cases) was significantly higher than in the non-IH group (2.3 +/- 0.5 vs. 1.8 +/- 0.6: P < 0.01) one month later, while RWMSI in both groups was almost the same shortly after reperfusion. The IH group showed a significantly higher value of C-IB than the non-IH group (18.6 +/- 2.0 vs. 16.0 +/- 1.4: P < 0.01), while there were no significant differences in CV values between two groups. Using 17 as a cutoff value of C-IB, C-IB can detect IH with 92% sensitivity and 91% specificity. Using both CV and C-IB, however, IH can be detected more specifically. Conclusion: Ultrasonic IBS, especially C-IB, discloses intramyocardial hemorrhage in patients with reperfused AMI.