Changes in first-pass interstitial kinetics of DTPA in myocardium submitted to low-flow ischemia.
OBJECTIVE
This study aimed to determine the changes during ischemia in the myocardial first-pass kinetics of DTPA, an extracellular tracer that is currently used for assessing myocardial perfusion with magnetic resonance imaging (Magnevist).


METHODS
Using an indicator-dilution technique, first-pass kinetics of DTPA were compared between normoxia (n=11) and low-flow ischemia (n=11) in isolated rabbit hearts perfused with red blood cell-enhanced perfusate.


RESULTS
There was no difference between ischemia and normoxia in the interstitial extraction and clearance rates of DTPA. Interstitial distribution volume of DTPA was, however, lower in ischemia than in normoxia (in percent of myocardial volume: 15+/-11% vs 25+/-11%, P=0.02) as a result of a relationship with coronary flow (P<0.001).


CONCLUSIONS
During low-flow myocardial ischemia, DTPA kinetics are unchanged, except for the interstitial distribution volume that is decreased, presumably because of the shrinkage of extracellular fluid. These kinetic properties are favorable for detecting myocardial ischemia at rest with magnetic resonance imaging.
Maskali
Fatiha
F
Department of Nuclear Medicine, Unité mixte UHP-Inserm U684, and the Laboratory of Hematology and Physiology, Faculty of Pharmacy, University Henri Poincaré, Nancy, France. Fatiha.Maskali@medecine.uhp-nancy.fr
Ayalew
Adey
A
Marie
Pierre-Yves
PY
Menu
Patrick
P
Antunes
Laurent
L
Mertes
Paul-Michel
PM
Zannad
Faïez
F
Gravier
Jean-Marc
JM
Karcher
Gilles
G
Bertrand
Alain
A
D000818:Animals; D003198:Computer Simulation; D003287:Contrast Media; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007700:Kinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008657:Metabolic Clearance Rate; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000473:pathology*; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D019786:Gadolinium DTPA