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Detection and localization of recent myocardial infarction by magnetic resonance imaging
Abstract:
The potential of magnetic resonance imaging (MRI) to detect and localize acute myocardial infarction (AMI) in 27 patients a mean interval of 15 days after AMI was evaluated. Eighteen asymptomatic volunteers were also studied to determine the specificity of the observations. The diagnosis of AMI was established by conventional criteria; the infarct was localized by electrocardiography in all patients, technetium pyrophosphate scintigraphy in 19 and necropsy in 1 patient. MRI detected increased myocardial signal intensity in 88%, cavitary signal in 74% and regional wall thinning in 67% of the patients. At least 1 of these 3 features was seen in the area of the infarct in each patient. The sensitivity of these MRI observations was not influenced by location of the infarct or presence of Q waves. Asymptomatic volunteers also had increased myocardial signal in 83%, cavitary signal in 94% and wall thinning in 11% of cases. Some patients had these findings in myocardial segments not suspected of being involved by recent or remote AMI. It is concluded that AMI can be detected by MRI performed an average of 15 days after infarction. However, the hearts of normal volunteers and apparently normal myocardial segments of patients with AMI may have the MRI findings previously associated with AMI. Of these findings, wall thinning was the most predictive of and specific for AMI.
Insights
Magnetic resonance imaging (MRI) can detect acute myocardial infarction (AMI) 15 days post-event. However, findings like wall thinning in normal hearts necessitate careful interpretation for accurate AMI diagnosis.
Area of Science:
- Cardiovascular Imaging
- Diagnostic Radiology
- Medical Physics
Background:
- Acute myocardial infarction (AMI) diagnosis relies on various methods.
- Magnetic resonance imaging (MRI) offers advanced visualization of cardiac tissue.
- Assessing MRI's utility for detecting and localizing AMI is crucial.
Purpose of the Study:
- To evaluate the potential of MRI in detecting and localizing acute myocardial infarction (AMI).
- To determine the specificity of MRI findings in normal individuals.
Main Methods:
- MRI was performed on 27 patients with established AMI (mean 15 days post-event).
- Eighteen asymptomatic volunteers were studied for comparison.
- Conventional criteria, ECG, scintigraphy, and necropsy confirmed AMI diagnosis and localization.
Main Results:
- MRI detected increased myocardial signal intensity (88%), cavitary signal (74%), and regional wall thinning (67%) in AMI patients.
- At least one MRI feature was present in the infarct area for all patients.
- Normal volunteers showed high rates of increased signal (83%) and cavitary signal (94%), with lower wall thinning (11%).
- Wall thinning demonstrated the highest specificity for AMI.
Conclusions:
- MRI can detect acute myocardial infarction (AMI) approximately 15 days after the event.
- MRI findings associated with AMI can also be present in normal volunteers and unaffected myocardial segments.
- Wall thinning is the most reliable MRI indicator for diagnosing AMI.