Oxygenation-sensitive CMR for assessing vasodilator-induced changes of myocardial oxygenation.
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 (r2 = 0.74, P < 0.001). Both SvO2 and 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 SvO2 and 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.
Vöhringer
Matthias
M
Stephenson Cardiovascular MR Centre at the Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, AB, Canada.
Flewitt
Jacqueline A
JA
Green
Jordin D
JD
Dharmakumar
Rohan
R
Wang
Jiun
J
Tyberg
John V
JV
Friedrich
Matthias G
MG
D000109:Acetylcholine; D000241:Adenosine; D000818:Animals; D001783:Blood Flow Velocity; D003287:Contrast Media; D003326:Coronary Circulation; D004195:Disease Models, Animal; D004285:Dogs; D019786:Gadolinium DTPA; D006940:Hyperemia / Q000097:blood* / Q000139:chemically induced / Q000503:physiopathology; D019028:Magnetic Resonance Imaging, Cine; D008833:Microcirculation; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D013997:Time Factors; D014665:Vasodilator Agents
D003287:Contrast Media; D014665:Vasodilator Agents; D019786:Gadolinium DTPA; D000241:Adenosine; D000109:Acetylcholine; D010100:Oxygen