Myocardial area at risk
Myocardial area at risk (AAR) is defined by the ischemic proportion of the myocardium after coronary occlusion and reflects the potential size of the myocardial infarction .
Usage
The assessment of myocardial area at risk is an important measure in the evaluation of the potentially salvageable myocardium by means of therapeutic approaches like coronary reperfusion .
Measurement
The myocardial area at risk (AAR) can be assessed by different means in cardiac magnetic resonance, including T2W/STIR imaging, T2 mapping, T1 mapping, early gadolinium enhancement, contrast-enhanced steady-state free precession and extracellular volume (ECV) imaging as well with SPECT and angiographic scores .
Interpretation
MRI
The more traditional approach for assessing myocardial area at risk (AAR) with T2/STIR and more recently with T2 and T1 mapping techniques are founded on the assumption that post-infarct myocardial edema also reflects reversibly injured myocardium respectively the area at risk (AAR) .
However, limitations of this approach are that the affected myocardial region is highly dynamic within the postinfarct period and myocardial edema is not quite as stable as previously thought and influenced by cardioprotective measures, which has risen doubts about the above-mentioned concept .
Early gadolinium enhancement, extracellular volume (ECV) imaging and contrast-enhanced steady-state free precession are contrast based quantification methods, which have been proposed as a different approach of assessing myocardial area at risk, in which the process model seems not quite clear as yet .
Angiography (DSA)
The modified APPROACH score, which takes the site of coronary occlusion, coronary dominance, and the size of major branches into account is one means to determine area at risk, another one is the BARI score .
See also
