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Usefulness of magnetic resonance imaging early after acute myocardial infarction
C M Kramer1, W J Rogers, G Geskin
1Department of Medicine, Allegheny Campus, Allegheny University of the Health Sciences, Pittsburgh, Pennsylvania, USA.
Abstract:
In patients, early after acute myocardial infarction (AMI), rapid magnetic resonance imaging (MRI) techniques have been used to assess left ventricular (LV) structure, global and regional function, infarct artery patency, or contrast uptake individually. We hypothesized that MRI could be used as a comprehensive evaluation of the post-AMI patient, studying all of these parameters in < 1 hour. Twenty-seven patients were studied after first AMI. Complete examinations were performed in 23 patients, 16 with anterior and 7 with inferior wall myocardial infarction, on day 5 +/- 2 after the event. For measurement of LV structure and regional function, a breath-hold segmented k-space gradient echo tagging sequence was used. A fat-suppressed segmented k-space breath-hold sequence was used for coronary artery imaging. MRI contrast-enhanced images during bolus gadoteridol transit through the myocardium were obtained to assess first-pass contrast uptake. No adverse events were noted during the MRI scanning, which was completed in 46 +/- 5 minutes. The LV mass index, end-diastolic and end-systolic volume indexes, and ejection fraction were (mean +/- SD) 107 +/- 13 g/m2, 87 +/- 23 ml/m2, 54 +/- 20 ml/m2, and 39 +/- 12%, respectively. Intramyocardial percent circumferential shortening was 11 +/- 6% at the apex, 14 +/- 4% in the midventricle, and 15 +/- 4% at the base. Flow within all infarct arteries was visualized. Seventeen of 23 patients had regions of reduced contrast uptake on first-pass imaging with mean signal intensity of 47 +/- 24% that of remote regions. In patients with recent AMI, comprehensive assessment of LV structure and function, infarct artery patency, and regional myocardial contrast uptake was safe and feasible with MRI of < 1 hour.
Insights
Rapid magnetic resonance imaging (MRI) provides a comprehensive evaluation for acute myocardial infarction (AMI) patients, assessing cardiac structure, function, and blood flow in under an hour. This safe and feasible technique offers detailed insights into post-AMI recovery and heart health.
Area of Science:
- Cardiovascular Imaging
- Medical Diagnostics
- Radiology
Background:
- Acute myocardial infarction (AMI) requires timely and comprehensive patient assessment.
- Current magnetic resonance imaging (MRI) techniques often evaluate specific parameters post-AMI individually.
- A need exists for a rapid, integrated MRI approach to assess multiple aspects of cardiac health after AMI.
Purpose of the Study:
- To determine the feasibility and safety of a comprehensive, rapid MRI protocol for evaluating patients early after AMI.
- To assess left ventricular (LV) structure, global and regional function, infarct artery patency, and myocardial contrast uptake within one hour.
- To test the hypothesis that a single, rapid MRI session can provide a complete picture of the post-AMI cardiac status.
Main Methods:
- A rapid MRI protocol was developed and applied to 23 patients within 5 days of their first AMI.
- Techniques included breath-hold segmented k-space gradient echo tagging for LV structure/function and fat-suppressed sequences for coronary artery imaging.
- First-pass contrast-enhanced MRI with gadoteridol was used to assess myocardial contrast uptake and infarct artery patency.
Main Results:
- The complete MRI examinations were performed safely in an average of 46 +/- 5 minutes.
- Detailed LV structure, global function (ejection fraction 39 +/- 12%), and regional function (circumferential shortening 11-15%) were quantified.
- Infarct artery patency was visualized, and 17 patients showed reduced contrast uptake in infarcted regions (53% of remote signal intensity).
Conclusions:
- Comprehensive assessment of LV structure, function, infarct artery patency, and myocardial contrast uptake is safe and feasible using rapid MRI in patients with recent AMI.
- A rapid MRI protocol (< 1 hour) can provide integrated diagnostic information for post-AMI patients.
- This approach enhances the evaluation of cardiac status and recovery following acute myocardial infarction.