title: 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 (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.
authors.affiliation: Stephenson Cardiovascular MR Centre at the Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, AB, Canada.
authors.forename: Matthias
authors.initials: M
authors.lastname: Vöhringer
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Flewitt
authors.forename: Jordin D
authors.initials: JD
authors.lastname: Green
authors.forename: Rohan
authors.initials: R
authors.lastname: Dharmakumar
authors.forename: Jiun
authors.initials: J
authors.lastname: Wang
authors.forename: John V
authors.initials: JV
authors.lastname: Tyberg
authors.forename: Matthias G
authors.initials: MG
authors.lastname: Friedrich
mesh_terms: 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
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents; D019786:Gadolinium DTPA; D000241:Adenosine; D000109:Acetylcholine; D010100:Oxygen