ANALYSIS OF TRANSMURAL TREND OF MYOCARDIAL INTEGRATED ULTRASONIC BACKSCATTER IN PATIENTS WITH OLD MYOCARDIAL-INFARCTION

Changes in myocardial integrated backscatter (IB) reflect myocardial v iability in patients with myocardial infarction, IB may be obtained se parately in the subendocardial and subepicardial layers to establish a transmural trend, The purpose of this study is to examine the possibi lities that the measurement of the transmural trend in myocardial IB m ay provide a new estimate of transmurality of infarction in patients w ith old myocardial infarction, A calibrated myocardial IB and its tran smural trend were measured both in the septum and posterior wall in 21 normal subjects, 24 patients with anteroseptal old myocardial infarct ion (13 patients with Q-wave myocardial infarction and 11 patients wit h non-Q-wave myocardial infarction), The transmural trend in myocardia l IB was assessed by measuring the acoustic parameter separately in th e right and left ventricular halves of the septum, and in the endocard ial and epicardial halves of the posterior wall, The magnitude of cycl ic variation of IB (a difference between minimum and maximum peaks) wa s lower, and calibrated myocardial IB (the maximum value of myocardial IB at end diastole calibrated with the power of Doppler signals from the blood along the same ultrasound beam) was higher in patients with anteroseptal old myocardial infarction in the septum, compared with no rmal subjects. Among patients with myocardial infarction, the differen ce in these IB parameters between the right and left ventricular halve s of the septum was found only in patients with non-Q-wave myocardial infarction, The transmural trend of myocardial IB was likely to reflec t the transmurality of myocardial infarction, Therefore, our data give another insight into the assessment of transmural inhomogeneity of my ocardial fibrosis or viability in patients with myocardial infarction.