Myocardial clearance kinetics of technetium-99m-SQ30217: a marker of regional myocardial blood flow.
SQ30217 is a new, technetium-99m-(99mTc) labeled perfusion agent introduced for cardiac imaging. To evaluate the myocardial tracer kinetics, 99mTc-SQ30217, was injected intracoronarily in open-chested dogs under baseline conditions and after administration of intravenous (i.v.) dipyridamole. Myocardial first-pass retention fraction averaged 0.90 +/- 0.04. Clearance of the tracer occurred in a biexponential manner. Sixty-seven percent of retained activity cleared with a half-time of 2.3 +/- 0.6 min, while the residual activity demonstrated slow clearance. The clearance rate of the rapid phase correlated with myocardial blood flow (r = 0.72, p less than 0.001). Myocardial SQ30217 clearance rate following i.v. injection as determined by dynamic imaging with tomography (SPRINT) averaged 21 +/- 4 min and increased to 13 +/- 4 min following dipyridamole. Thus, 99mTc-SQ30217 is a promising flow tracer with high initial myocardial retention and rapid tissue clearance, which allow repeated flow determinations within short time intervals using advanced SPECT technology.
Stewart
R E
RE
Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109.
Schwaiger
M
M
Hutchins
G D
GD
Chiao
P C
PC
Gallagher
K P
KP
Nguyen
N
N
Petry
N A
NA
Rogers
W L
WL
D000818:Animals; D003326:Coronary Circulation; D004285:Dogs; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D008297:Male; D008657:Metabolic Clearance Rate; D009206:Myocardium / Q000378:metabolism*; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics*; D010091:Oximes / Q000493:pharmacokinetics*; D012039:Regional Blood Flow; D015899:Tomography, Emission-Computed, Single-Photon
D015609:Organotechnetium Compounds; D010091:Oximes; C060156:technetium Tc 99m teboroxime