Measurement of the extraction efficiency and distribution volume for Gd-DTPA in normal and diseased canine myocardium.
We have previously shown that the myocardial Gd-DTPA concentration ([Gd-DTPA]t(t)) after a bolus injection of Gd-DTPA can be predicted by the Modified Kety Equation (MKE). If [Gd-DTPA]t(t) can be determined by MRI and the data fit to the MKE, then the distribution volume (lambda) of Gd-DTPA and the myocardial flow (F) times the extraction efficiency (E), i.e., the FE product, can be determined. Therefore F can only be quantified if E is known. We measured the global E in vivo in normal canine myocardium, and measured E and lambda, in vitro, locally in normal, acute ischemic (n = 5; coronary artery occlusion < 4 h), infarcted (n = 4; coronary artery occlusion, 6 days) and reperfused (n = 4; coronary artery occlusion 2 h, and reperfusion 2 h and 6 days) myocardium. Results indicate that E differs with F and with individuals and consequently, F cannot be quantified using the MKE unless the local E is also determined in vivo.
Tong
C Y
CY
Department of Physics, St. Joseph's Health Centre, University of Western Ontario, London, Canada.
Prato
F S
FS
Wisenberg
G
G
Lee
T Y
TY
Carroll
E
E
Sandler
D
D
Wills
J
J
Drost
D
D
D000818:Animals; D003287:Contrast Media; D003326:Coronary Circulation / Q000502:physiology; D004285:Dogs; D005260:Female; D005682:Gadolinium; D019786:Gadolinium DTPA; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009203:Myocardial Infarction / Q000175:diagnosis*; D017202:Myocardial Ischemia / Q000175:diagnosis*; D015428:Myocardial Reperfusion Injury / Q000175:diagnosis*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives*
D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA