Cardiac magnetic resonance imaging of acute myocardial infarction

Abstract

Area at risk, infarct area, the size of no-reflow phenomenon and finally left ventricular function determine immediate and long-term outcome in patients with acute myocardial infarction (AMI). Cardiac magnetic resonance imaging is a gold standard technique for evaluation of left ventricular volumes and function and therefore has evolved into an important diagnostic tool in the assessment of patients with AMI. Increased free water content in the infracted myocardium prolongs the T2-relaxation time. Differences in T2-relaxation time are clinically useful for detection of area of risk whereas first-pass technique is useful for the assessment of areas with perfusion deficit at rest. Myocardial necrosis appears hyper-enhanced in comparison to the normal myocardium after contrast injection with delayed enhancement (DE) technique. Experimental and clinical studies indicate that extent of DE closely correlates with infarct size and predicts functional recovery of postinfarcted myocardium. The hypo-enhanced zone usually located in the core of hyper-enhanced region indicates microvascular obstruction (MVO) and corresponds with the area of no-reflow as defined by histopathology. The presence of MVO is associated with impaired functional recovery after AMI.
Kardiol Pol 2010; 68, supl. V: 441-447