Measurement of phosphocreatine to ATP ratio in normal and diseased human heart by 31P magnetic resonance spectroscopy using the rotating frame-depth selection technique.
31P magnetic resonance spectroscopy, using surface coils placed on perfused or surgically exposed animal hearts, shows that unequivocal changes in phosphocreatine (PCr) and adenosine triphosphate (ATP) occur during interventions, such as ischemia. Similar measurements seem warranted in man. We have used a modification of the rotating-frame imaging technique to measure PCr-to-ATP ratio non-invasively in human heart. The subject lay prone on a double-surface coil probe with the apex and the anterior surface of the heart covered by the coil in a 1.9 T magnet. 31P spectra were obtained from slices of tissue approximately 6 cm in diameter and 2 cm in thickness. Though skeletal and cardiac muscle contain similar phosphorus metabolites, animal studies show that the ratio in the two are different. We argued that the ratio should start high (skeletal muscle) and plateau at a low value representing cardiac muscle. Using this criterion, which makes no assumption on what the ratio is in heart muscle, the PCr:ATP in six normal subjects was 1.55 +/- 0.2. This protocol has been used in a preliminary study in patients with cardiomyopathies.
Rajagopalan
B
B
MRC Clinical Magnetic Resonance Facility, John Radcliffe Hospital, Headington, Oxford, England.
Blackledge
M J
MJ
McKenna
W J
WJ
Bolas
N
N
Radda
G K
GK
D000255:Adenosine Triphosphate / Q000378:metabolism*; D009202:Cardiomyopathies / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009206:Myocardium / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism*; D010758:Phosphorus; D012016:Reference Values
D010725:Phosphocreatine; D010758:Phosphorus; D000255:Adenosine Triphosphate