Reperfused rat myocardium subjected to various durations of ischemia: estimation of the distribution volume of contrast material with echo-planar MR imaging.
OBJECTIVE
To estimate and compare the fractional distribution volume (fDV) of gadodiamide injection and technetium 99m-diethylenetriaminepentaacetic acid (DTPA) in the reperfused myocardium of rat hearts subjected to various durations of ischemia.


METHODS
Magnetic resonance (MR) imaging and autoradiography were performed in rats subjected to 20, 30, 40, or 60 minutes of regional ischemia followed by 1 hour of reperfusion. The fDVs of gadodiamide injection and (99m)Tc-DTPA were measured and compared by using inversion-recovery echo-planar imaging and autoradiographic phosphor imaging, respectively.


RESULTS
The mean fDV of both tracers (gadodiamide and (99m)Tc-DTPA) in normal myocardium was 18% +/- 1, whereas that in the entire area at risk increased significantly (P <.05) with 20, 30, 40, and 60 minutes of ischemia to 32% +/- 1, 57% +/- 4, 66% +/- 2, and 68% +/- 2, respectively. The fDV was significantly (P <.05) greater in the core of infarction-78% +/- 4, 89% +/- 5, and 88% +/- 5 with 30, 40, and 60 minutes of ischemia, respectively-than in the normal myocardium or in the area at risk.


CONCLUSIONS
The fDV of MR contrast material in the periinfarcted rim was significantly (P <. 05) greater than that in the normal myocardium, but significantly less than that in the core of infarcted myocardium.
Arheden
H
H
Department of Radiology, University of California San Francisco, 505 Parnassus Ave, L308, San Francisco, CA 94143-0628, USA.
Saeed
M
M
Higgins
C B
CB
Gao
D W
DW
Ursell
P C
PC
Bremerich
J
J
Wyttenbach
R
R
Dae
M W
MW
Wendland
M F
MF
D000704:Analysis of Variance; D000818:Animals; D001345:Autoradiography; D004396:Coloring Agents; D003287:Contrast Media / Q000493:pharmacokinetics*; D017352:Echo-Planar Imaging; D005240:Feasibility Studies; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D007211:Indoles; D008279:Magnetic Resonance Imaging; D008854:Microscopy, Electron; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000473:pathology; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D016284:Technetium Tc 99m Pentetate / Q000493:pharmacokinetics; D013997:Time Factors; D014022:Tissue Survival
D004396:Coloring Agents; D003287:Contrast Media; D007211:Indoles; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C015445:copper phthalocyanine; D019786:Gadolinium DTPA; D016284:Technetium Tc 99m Pentetate