Role of Cardiac Magnetic Resonance Imaging in the Assessment of Myocardial Viability in Patients with Coronary Artery Disease

Abstract
Background: The principal goal of the assessment of myocardial viability is to identify patients whose symptoms, exercise capacity, and long-term prognosis may improve after revascularization. Contrast enhanced cardiac MRI has devel-oped as a promising imaging modality for the assessment of myocardial viability which provides direct imaging of necrotic tissue with high contrast and high spatial resolution. Aim of the work was to assess role of cardiac MRI as a non-invasive tool in the evaluation of myocardial viability in patients with coronary artery disease.
Aim of Study: To assess the role of cardiac MRI as a non-invasive tool in the evaluation of myocardial viability in patients with coronary artery disease.
Material and Methods: The study included 25 patients diagnosed as having Coronary Artery Disease (CAD), (age range, 28-68 years ±11.29). All selected patients were subjected to cardiac MRI examination using 1.5-T MR system for studying myocardial function and viability. Comparison was made between echocardiography and cardiac MRI regarding segmental wall motion using the 17-segment model of the American Heart Association for assessment of myocardial function. Delayed-enhancement MRI was performed to deter-mine myocardial viability and scarring while black blood T2W sequence with fat suppression was done to detect cases with acute infarction. Microvascular occlusion was diagnosed using early Gadolinium enhancement sequence.
Results: Good agreement between cardiac MRI and echocardiography regarding segmental wall motion with p-value of 0.065. Sensitivity and specificity of cardiac MRI for detecting SWMA were 93.6%, and 44.4% respectively. Myo-cardial viability was evaluated by cardiac MRI with the use of end-diastolic wall thickness, imaging of early and late enhancement after contrast administration. Late gadolinium enhancement allowed assessing state of myocardium and visualizing myocardial scar with its quantification. Two segments showed 1-25% transmural extent of myocardial wall infarction, while 120 segments showed 71-100% extent and 261 segments showed no enhancing scar.
Conclusion: Cardiac MR imaging is an effective and reliable method for the evaluation of myocardial function as compared to echocardiography. Also it is effective and reliable method for the evaluation of myocardial viability being able to assess both the infarct size and trans-murality and accord-ingly helps to predict functional recovery after revasculariza-tion.