Oxygenation-sensitive CMR for assessing vasodilator-induced changes of myocardial oxygenation

Abstract

Background. As myocardial oxygenation may serve as a marker for ischemia and microvascular dysfunction, it could be clinically useful to have a non-invasive measure of changes in myocardial oxygenation. However, the impact of induced blood flow changes on oxygenation is not well understood. We used oxygenation-sensitive CMR to assess the relations between myocardial oxygenation and coronary sinus blood oxygen saturation (SvO2) and coronary blood flow in a dog model in which hyperemia was induced by intracoronary administration of vasodilators. Results. During administration of acetylcholine and adenosine, CMR signal intensity correlated linearly with simultaneously measured SvO2(r 2 = 0.74, P < 0.001). Both SvO 2and CMR signal intensity were exponentially related to coronary blood flow, with SvO2 approaching 87%. Conclusions. Myocardial oxygenation as assessed with oxygenation-sensitive CMR imaging is linearly related to SvO 2and is exponentially related to vasodilator-induced increases of blood flow. Oxygenation-sensitive CMR may be useful to assess ischemia and microvascular function in patients. Its clinical utility should be evaluated. © 2010 Vöhringer et al; licensee BioMed Central Ltd.