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Myocardial integrated ultrasonic backscatter in patients with old myocardial infarction: comparison with radionuclide
J Naito1, T Masuyama, K Yamamoto
1First Department of Medicine, Osaka University School of Medicine, Suita, Japan.
Insights
This study found that calibrated myocardial integrated backscatter and cyclic variation in integrated backscatter can help assess myocardial viability in patients with old myocardial infarction, offering a noninvasive diagnostic approach.
Area of Science:
- Cardiology
- Biomedical Ultrasound
- Medical Imaging
Background:
- Myocardial infarction can lead to reduced heart function.
- Assessing myocardial viability is crucial for treatment decisions.
- Current methods for assessing viability have limitations.
Purpose of the Study:
- To evaluate integrated backscatter parameters for assessing myocardial viability.
- To compare integrated backscatter with radionuclide and echocardiographic methods.
- To determine the noninvasive potential of integrated backscatter in myocardial infarction patients.
Main Methods:
- Measured two integrated backscatter parameters: cyclic variation and calibrated integrated backscatter.
- Studied 21 normal subjects and 33 patients with old myocardial infarction.
- Compared integrated backscatter with thallium uptake (radionuclide) and echocardiography.
Main Results:
- Calibrated integrated backscatter was higher in infarct septum compared to normal controls.
- Cyclic variation in integrated backscatter was lower in infarct septum.
- Calibrated integrated backscatter correlated well with thallium uptake (r = -0.72).
- Cyclic variation in integrated backscatter showed a weaker correlation with thallium uptake (r = 0.55).
Conclusions:
- Integrated backscatter parameters show promise for noninvasive myocardial viability assessment.
- Calibrated integrated backscatter may be a valuable tool alongside cyclic variation.
- These ultrasound-based methods could improve patient management after myocardial infarction.
Abstract:
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 persons 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.