Myocardial integrated ultrasonic backscatter in patients with old myocardial infarction: Comparison with radionuclide evaluation

The purpose of our study was to clarify whether the abnormalities in integrated backscatter may be used to assess myocardial viability in patients with old myocardial infarction by comparing these integrated backscatter parameters with conventional radionuclide and echocardiographic estimates of myocardial viability. Two myocardial integrated backscatter parameters, the magnitude of cyclic variation in integrated backscatter and the myocardial integrated backscatter calibrated with the power of Doppler signals from the blood along the same ultrasound beam (calibrated myocardial integrated backscatter), were measured in 21 normal parsons and 33 patients with old anteroseptal myocardial infarction. Calibrated myocardial integrated backscatter was higher and the magnitude of cyclic variation in integrated backscatter was lower in the infarct septum compared with the septum of normal subjects. Percent thallium uptake, as assessed in scintigraphic images taken at rest or after reinjection, correlated well with the calibrated myocardial integrated backscatter (r = -0.72, p< 0.01) and more weakly but significantly with the magnitude of cyclic variation in integrated backscatter (r = 0.55, p < 0.05) in 16 of 33 patients. The measurement of calibrated myocardial integrated backscatter, in addition to the magnitude of cyclic variation of integrated backscatter, may likely be valuable in the noninvasive assessment of myocardial viability.