Clinical use of cardiac computed tomography is rapidly expanding, and its purpose may reach beyond noninvasive coronary angiography. We investigated the ability of 64-slice multidetector computed tomography to differe...Clinical use of cardiac computed tomography is rapidly expanding, and its purpose may reach beyond noninvasive coronary angiography. We investigated the ability of 64-slice multidetector computed tomography to differentiate between recent and long-standing myocardial infarction(MI). Contrast-enhanced coronary computed tomographic(CT) scans(Siemens Sensation 64) of patients with a recent MI(< 7 days, n=16), long-standing MI( >12 months,n=13), and no MI(n=13)were retrospectively evaluated. To anticipate transmural variation of myocardial perfusion and to neutralize image noise, a series of thin, overlapping slices was created in parallel alignment to the myocardial wall. Within each of these slices, a small region of interest was placed at a constant in-plane position to measure the CT attenuation(Hounsfield units[HU]) at consecutive transmural locations of injured and normal remote myocardium. In addition, wall thickness and the myocardial cavity were measured. Significantly lower CT attenuation values were found in patients with long-standing MI(-13±37 HU) than in those with acute MI(26±26 HU) and normal controls(73±14 HU, p< 0.001). The attenuation difference between infarcted and remote myocardia was larger in patients with long-standing MI than in patients with recent MI(89±41 and 55±33 HU, respectively, p< 0.001). In addition, long-standing MI was associated with wall thinning(p< 0.01), and ventricular dilation(p< 0.05), whereas recent MI was not(p >0.05). In conclusion, recent and long-standing MIs may be differentiated by computed tomography based on myocardial CT attenuation values and ventricular dimensions.展开更多
Objective: To study the relation between resolution of ST segment devia tion an d infarct size using positron emission tomography. Methods: 45 patients with ST segment elevation acute myocardial infarction treated wit...Objective: To study the relation between resolution of ST segment devia tion an d infarct size using positron emission tomography. Methods: 45 patients with ST segment elevation acute myocardial infarction treated with thrombolysis or percu taneous coronary intervention were studied prospectively. An ECG was taken befor e and at (mean (SD)) 100 (45) min after reperfusion therapy. ECGs were analysed by three methods. Residual ST segment deviation, obtained from the ECG immediate ly after completion of reperfusion therapy, was defined by summation for each of the three methods. Relative resolution of ST segment deviation was defined as t he absolute resolution divided by the ST segment deviation score at baseline x 1 00(%). After 29 (14) hours, myocardial blood flow was measured with 13NH3. For each patient, the regions with a myocardial blood flow < 80%of normally perfuse d myocardium (=hypoperfusion) and < 50%(=no reflow) were automatically delineat ed. Results: Substantial differences were found between different ECG analysis m ethods. There were moderate correlations between the area with myocardial hypope rfusion and ST segment deviation scores at baseline and after reperfusion therap y. After reperfusion therapy, residual ST segment deviation in the single lead w ith maximum ST segment deviation was as good at discriminating between fertiles of myocardial damage as summed ST segment elevation. Relative ST segment resolut ion did not discriminate between different degrees of myocardial damage. Conclus ions: In the individual patient, residual ST segment deviation after reperfusion in the single lead with maximum ST segment deviation is at least as good as sum med ST elevation in predicting final myocardial damage.展开更多
文摘Clinical use of cardiac computed tomography is rapidly expanding, and its purpose may reach beyond noninvasive coronary angiography. We investigated the ability of 64-slice multidetector computed tomography to differentiate between recent and long-standing myocardial infarction(MI). Contrast-enhanced coronary computed tomographic(CT) scans(Siemens Sensation 64) of patients with a recent MI(< 7 days, n=16), long-standing MI( >12 months,n=13), and no MI(n=13)were retrospectively evaluated. To anticipate transmural variation of myocardial perfusion and to neutralize image noise, a series of thin, overlapping slices was created in parallel alignment to the myocardial wall. Within each of these slices, a small region of interest was placed at a constant in-plane position to measure the CT attenuation(Hounsfield units[HU]) at consecutive transmural locations of injured and normal remote myocardium. In addition, wall thickness and the myocardial cavity were measured. Significantly lower CT attenuation values were found in patients with long-standing MI(-13±37 HU) than in those with acute MI(26±26 HU) and normal controls(73±14 HU, p< 0.001). The attenuation difference between infarcted and remote myocardia was larger in patients with long-standing MI than in patients with recent MI(89±41 and 55±33 HU, respectively, p< 0.001). In addition, long-standing MI was associated with wall thinning(p< 0.01), and ventricular dilation(p< 0.05), whereas recent MI was not(p >0.05). In conclusion, recent and long-standing MIs may be differentiated by computed tomography based on myocardial CT attenuation values and ventricular dimensions.
文摘Objective: To study the relation between resolution of ST segment devia tion an d infarct size using positron emission tomography. Methods: 45 patients with ST segment elevation acute myocardial infarction treated with thrombolysis or percu taneous coronary intervention were studied prospectively. An ECG was taken befor e and at (mean (SD)) 100 (45) min after reperfusion therapy. ECGs were analysed by three methods. Residual ST segment deviation, obtained from the ECG immediate ly after completion of reperfusion therapy, was defined by summation for each of the three methods. Relative resolution of ST segment deviation was defined as t he absolute resolution divided by the ST segment deviation score at baseline x 1 00(%). After 29 (14) hours, myocardial blood flow was measured with 13NH3. For each patient, the regions with a myocardial blood flow < 80%of normally perfuse d myocardium (=hypoperfusion) and < 50%(=no reflow) were automatically delineat ed. Results: Substantial differences were found between different ECG analysis m ethods. There were moderate correlations between the area with myocardial hypope rfusion and ST segment deviation scores at baseline and after reperfusion therap y. After reperfusion therapy, residual ST segment deviation in the single lead w ith maximum ST segment deviation was as good at discriminating between fertiles of myocardial damage as summed ST segment elevation. Relative ST segment resolut ion did not discriminate between different degrees of myocardial damage. Conclus ions: In the individual patient, residual ST segment deviation after reperfusion in the single lead with maximum ST segment deviation is at least as good as sum med ST elevation in predicting final myocardial damage.
