Delayed Hyper-Enhancement in Cardiac MRI Compared to Nuclear Perfusion Scintigraphy in Identification of Viable Myocardium in Patients of Myocardial Infarction – A Study

摘要

Background: Myocardial infarction is the leading cause of death and disability worldwide. Nuclear perfusion scintigraphy is the gold-standard technique, which is highly specific in differentiating viable from scarred myocardium in patients of myocardial infarction. Dysfunctional myocardium with areas of residual viable tissue may show functional recovery after revascularization. The aim of this study was to determine the effectiveness of Cardiac MRI in detecting viability of myocardial tissue as compared to 99m-TC Sestamibi perfusion scan in patients with myocardial dysfunction who were awaiting revascularization procedures. Study methods: 42 patients (35 male and 07 females) of myocardial infarction in age group 31-76 yrs were evaluated using cardiac MRI and cardiac nuclear perfusion scans and the results were compared. Pearson Chi-Square test and Fisher’s Exact Test were used for statistical evaluation. P value <0.005 was considered statistically significant. Results: Both the techniques detected trans-mural myocardial infarcts at similar rates. However, cardiac MRI was able to detect sub-endocardial infarcts in 33% cases, which were totally missed on nuclear perfusion imaging. MRI was found to be more sensitive than nuclear perfusion scans for detecting sub-endocardial infarcts. The sensitivity of delayed hyper enhancement cardiac MRI for detection of viable myocardium was 100 % with a specificity of 47.83 %. The positive predictive value of the modality was 61.29 % with a diagnostic accuracy of 71.43 %. Conclusion: Contrast enhanced MRI was found to detect sub-endocardial infarcts at a higher rate and has high sensitivity in the detection of viable and irreversibly damaged myocardium in comparison to nuclear perfusion scans.