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.
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Kyle S
KS
McCommis
Xiang
X
He
Dana R
DR
Abendschein
Pradeep M
PM
Gupte
Robert J
RJ
Gropler
Jie
J
Zheng
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