Performance of CMR Methods for Differentiating Acute From Chronic MI
Martijn W Smulders1, Sebastiaan C A M Bekkers1, Han W Kim2
1Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands.
Objectives:
The purpose of this study was to assess the performance of cardiac magnetic resonance (CMR) methods for discriminating acute from chronic myocardial infarction (MI).
Background:
Although T2-weighted CMR is thought to be accurate in differentiating acute from chronic MI, few studies have reported on diagnostic accuracy, and these generally compared extremes in infarct age (e.g., <1 week old vs. more than 6 months old) and did not evaluate other CMR methods that could be informative.
Methods:
A total of 221 CMR studies were performed at various time points after ST-segment elevation myocardial infarction in 117 consecutive patients without a history of MI or revascularization enrolled prospectively at 2 centers. Imaging markers of acute MI (<1 month) were T2 hyperintensity on double inversion recovery turbo spin echo (DIR-TSE) images, microvascular obstruction (MO) on delayed-enhancement CMR, and focally increased end-diastolic wall thickness (EDWT) on cine-CMR.
Results:
The prevalence of T2-DIR-TSE hyperintensity decreased with infarct age but remained substantial up to 6 months post-MI. In contrast, the prevalence of both MO and increased EDWT dropped sharply after 1 month. T2-DIR-TSE sensitivity, specificity, and accuracy for identifying acute MI were 88%, 66%, and 77% compared with 73%, 97%, and 85%, respectively, for the combination of MO or increased EDWT. On multivariable analysis, persistence of T2-hyperintensity in intermediate-age infarcts (1 to 6 months old) was predicted by larger infarct size, diabetes, and better T2-DIR-TSE image quality score. For infarct size ≥ 10% of the left ventricle, a simple algorithm incorporating all CMR components allowed classification of infarct age into 3 categories (<1 month old, 1 to 6 months old, and ≥ 6 months old) with 80% (95% confidence interval: 73% to 87%) accuracy.
Conclusions:
T2-DIR-TSE hyperintensity is specific for infarcts <6 months old, whereas MO and increased EDWT are specific for infarcts <1 month old. Incorporating multiple CMR markers of acute MI and their varied longevity leads to a more precise assessment of infarct age.
Insights
Cardiac MRI markers help differentiate acute from chronic myocardial infarction (MI). T2-weighted imaging is specific for infarcts under 6 months, while microvascular obstruction and wall thickening indicate recent MI (<1 month).
Area of Science:
- Cardiology
- Radiology
- Medical Imaging
Background:
- T2-weighted cardiac magnetic resonance (CMR) is used to differentiate acute from chronic myocardial infarction (MI).
- Previous studies had limited diagnostic accuracy and compared extreme infarct ages, not evaluating other informative CMR methods.
Purpose of the Study:
- To assess the performance of cardiac magnetic resonance (CMR) methods for discriminating acute from chronic myocardial infarction (MI).
Main Methods:
- 221 CMR studies were performed in 117 patients post-ST-segment elevation myocardial infarction.
- Imaging markers included T2 hyperintensity (double inversion recovery turbo spin echo - DIR-TSE), microvascular obstruction (MO), and increased end-diastolic wall thickness (EDWT).
Main Results:
- T2-DIR-TSE hyperintensity decreased with infarct age but persisted up to 6 months.
- MO and increased EDWT sharply dropped after 1 month.
- T2-DIR-TSE sensitivity/specificity/accuracy was 88%/66%/77%; MO or increased EDWT was 73%/97%/85% for acute MI. An algorithm incorporating CMR markers achieved 80% accuracy in classifying infarct age.
Conclusions:
- T2-DIR-TSE hyperintensity is specific for infarcts <6 months old.
- MO and increased EDWT are specific for infarcts <1 month old.
- Combining multiple CMR markers provides a more precise assessment of myocardial infarction age.
Related Concept Videos
01:21Imaging Studies for Cardiovascular System IV: CMRI
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:30Acute Coronary Syndrome I: Introduction
01:19Acute Coronary Syndrome II: Pathophysiology and Clinical Manifestations
01:29Cardiomyopathy IV: Restrictive Cardiomyopathy
01:27Myocarditis II: Clinical Features and Diagnostic Tests