Kinetics of copper-PTSM in isolated hearts: a novel tracer for measuring blood flow with positron emission tomography.
Copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone) ([Cu]PTSM) has shown potential as a flow tracer and can be labeled with the generator-produced positron emitting radionuclide 62Cu as well as with other copper radioisotopes. To define the myocardial handling of [Cu]PTSM, the externally detected single pass extraction and retention of [67Cu]PTSM was characterized after bolus administration in 12 isolated rabbit hearts perfused with erythrocyte-enriched modified Krebs-Henseleit buffer which permitted physiologic flow rates. The myocardial residual (extraction) fraction at control flow rates (approximately 1.5 ml/g/min) was 45 +/- 7(s.d.)% (n = 12), and was invariate with ischemia (flow = 0.15 ml/g/min, n = 4), hyperemia (flow = 3 ml/g/min, n = 4) or with hypoxia induced by perfusion at control flow rates with hypoxic buffer (n = 4) (residual fraction 45 +/- 20, 43 +/- 8, and 49 +/- 8%, respectively, p = N.S.). Once extracted, the tracer was retained with a biologic t1/2 of greater than 3600 min in all groups. The high single-pass extraction, which is not influenced by flow, and the prolonged retention of this tracer under diverse conditions indicate that [Cu]PTSM could be a useful tracer for measuring blood flow with positron emission tomography.
Shelton
M E
ME
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
Green
M A
MA
Mathias
C J
CJ
Welch
M J
MJ
Bergmann
S R
SR
D000818:Animals; D003301:Copper Radioisotopes; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D006207:Half-Life; D006321:Heart / Q000000981:diagnostic imaging; D009206:Myocardium / Q000378:metabolism*; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D010477:Perfusion; D011817:Rabbits; D012039:Regional Blood Flow; D013882:Thiosemicarbazones; D014055:Tomography, Emission-Computed
D003301:Copper Radioisotopes; D009942:Organometallic Compounds; D013882:Thiosemicarbazones; C052629:copper pyruvaldehyde bis(N(4)-methylthiosemicarbazone) complex