Cardiac 17O MRI: toward direct quantification of myocardial oxygen consumption.
A new (17)O-labeled blood contrast agent was injected intravenously in control dogs. Electrocardiogram (ECG)-triggered myocardial T(1)rho imaging was performed to obtain spin-locking T(1)rho-weighted myocardial signals for the detection of resultant metabolite H(2) (17)O water in the heart. Bolus and slow injection methods of various doses of the (17)O-labeled and (16)O-labeled agents were carried out in order to evaluate the sensitivity of this method and determine the optimal injection method. Bolus injection provided approximately 1% signal reduction, whereas slow injection with larger amount of agent yielded 11.9 +/- 0.6% signal reduction. Myocardial oxygen consumption rate was determined by a technique to quantify cerebral oxygenation consumption rate previously developed in (17)O brain studies. With either injection method, myocardial oxygen consumption rate at rest was 5.0 - 5.6 micromol/g/min. Therefore, it appears feasible to detect metabolically generated H(2) (17)O water in vivo in the heart, using the (17)O-labeled blood tracer. Myocardial oxygen consumption rate can then be quantified in vivo, which may open new doors for the assessment of myocardial metabolism.
McCommis
Kyle S
KS
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
He
Xiang
X
Abendschein
Dana R
DR
Gupte
Pradeep M
PM
Gropler
Robert J
RJ
Zheng
Jie
J
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D004285:Dogs; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D010103:Oxygen Isotopes; D019047:Phantoms, Imaging; D010865:Pilot Projects; D012015:Reference Standards
D003287:Contrast Media; D010103:Oxygen Isotopes