Summary: We investigated 26 patients admitted to our catheterization laboratory with a diagnosis of acute myocardial infarction. In each case acute revascularization was unsuccessful, but the diagnosis was confirmed by angiography. In 11 patients with an uncomplicated course of acute myocardial infarction magnetic resonance imaging was camed out within 7 days of the acute event. In three additional cases imaging was performed within 3 weeks, while a remaining 12 patients underwent studies more than 3 weeks after the onset of symptoms. We determined signal intensity at three points within the area of infarction and at three other points in adjacent myocardial tissue. Decreased signal intensity within the area of infarction was present in native scans in 60% of all cases. Application of 0. I mmol/kg body weight gadolinium-DTPA was followed by an average 70% increase in signal intensity within zones of acute infarction, as compared to a 20% increase in surrounding myocardial tissue. In cases of subacute and chronic infarction there was no significant signal enhancement after administration of gadolinium-DTPA. Uptake of gadolinium-DTPA in the area of acute myocardial infarction may be a positive marker of acute myocardial necrosis, which may be of potential clinical benefit.
The aim of this study was to assess whether a clinically relevant change in myocardial sestamibi activity could be documented within the first 120 min following injection (p.i.). In 17 patients planar anterior imaging of the heart was performed 5 min and 120 min p.i. During this time interval, mean decay-corrected myocardial activity declined to 77.9% +/- 9.7% after stress and to 85.7% +/- 7.9% after injection at rest (P < 0.05). In 19 patients with angiographically documented coronary artery disease, single-photon emission tomography was performed 5 min and 120 min after injection at maximum stress. For analysis, sestamibi activity was scored semiquantitatively in six left ventricular segments. Furthermore, sestamibi uptake was assessed quantitatively using a circumferential profile method. In 35 of 114 segments the score improved within 120 min p.i. (early fill-in); in these segments relative sestamibi activity rose from 69.9% +/- 22.5% to 74.5% +/- 20.8% (P < 0.01). In five patients this early fill-in was the only sign of exercise-induced hypoperfusion. In 7 of 114 segments the score deteriorated 120 min p.i. (early tracer washout); in these segments relative sestamibi activity declined from 85.6% +/- 9.9% to 80.1% +/- 10.7% (P < 0.02). In three of four patients with early tracer washout the corresponding coronary artery was significantly narrowed. In conclusion, a global myocardial sestamibi washout was registered within the first 120 min after injection. A fill-in of initial defects as well as an early tracer loss could be detected in a relevant number of patients with chronic coronary artery disease during the first 2 h p.i.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty-six patients admitted to the Free University of Berlin University Hospital catheterization laboratory with acute myocardial infarction were studied. The diagnosis was confirmed by angiography, but acute revascularization was unsuccessful in every case. MR imaging was performed within 7 days of the acute event in 11 patients with uncomplicated clinical courses after acute infarction. Imaging was performed within 3 weeks in three additional cases, while the remaining 12 patients underwent studies more than 3 weeks after infarction. We determined signal intensity at three points within the area of infarction and at three other points in adjacent myocardial tissue. Decreased signal intensity within the area of infarction was found in native scans in 60% of all cases. Administration of gadolinium-DTPA 0.1 mmol/kg body weight was followed by a mean 70% increase in signal intensity within the zones of acute infarction, as compared to a 20% increase in surrounding myocardial tissue. In cases of subacute and chronic infarction, there was no significant signal enhancement after administration of gadolinium-DTPA. Uptake of the substance in the area of acute infarction may be a positive marker of acute myocardial necrosis and as such may prove useful in the clinical setting.
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