Quantification of myocardial blood volume during dipyridamole and doubtamine stress: a perfusion CMR study.
OBJECTIVE
Myocardial blood volume (MBV) may provide complementary information about myocardial oxygen needs and viability. The aim of this study is to examine a Cardiovascular Magnetic Resonance (CMR) perfusion method to quantify the changes in MBV, in comparison with the radiolabeled 99mTc-Red-Blood-Cell (RBC) method.


METHODS
Normal mongrel dogs (n=12) were used in this study. Eight dogs were injected intravenously with dipyridamole, and 4 dogs were given dobutamine during the MR scans. CMR first-pass perfusion imaging was performed at rest and during the pharmacological stress. An intravascular contrast agent, Gadomer (Schering AG, Berlin, Germany), was injected (0.015 mmol/kg) as a bolus during the scans. A perfusion quantification method was applied to obtain MBV maps. Radiolabeled-RBCs were injected at the end of the study to measure reference MBV at rest (n=4), during dipyridamole vasodilation (n=4), and during dobutamine stress (n=4).


RESULTS
Myocardial blood flow (MBF) increased approximately 3-fold with both dipyridamole and dobutamine injections. Transmural MBV values measured by CMR were closely correlated with those measured by 99mTc method (CMR:MBV=6.2+/-1.3, 7.2+/-0.8, and 8.3+/-0.5 mL/100 g, at rest, with dipyridamole, and with dobutamine, respectively. 99mTc-RBC: MBV=6.1+/-0.5, 7.0+/-0.9, and 8.6+/-0.7 mL/100 g). Dobutamine stress significantly increased MBV by CMR (33%) and 99mTc methods (35%). During dipyridamole induced vasodilation, MBV increased non-significantly by 14% with the 99mTc method and 1% with CMR method, which agreed well with other reports.


CONCLUSIONS
First-pass perfusion CMR with the injection of intravascular contrast agents is a promising non-invasive approach for the assessment of MBV both at rest and pharmacologically induced stress.
McCommis
Kyle S
KS
Mallinkcrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Goldstein
Thomas A
TA
Zhang
Haosen
H
Misselwitz
Bernd
B
Gropler
Robert J
RJ
Zheng
Jie
J
D000818:Animals; D001810:Blood Volume; D002316:Cardiotonic Agents; D003287:Contrast Media; D003326:Coronary Circulation; D004176:Dipyridamole; D004280:Dobutamine; D004285:Dogs; D004912:Erythrocytes / Q000000981:diagnostic imaging; D005080:Exercise Test; D005682:Gadolinium; D006321:Heart / Q000000981:diagnostic imaging / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012107:Research Design; D013667:Technetium; D014665:Vasodilator Agents
D002316:Cardiotonic Agents; D003287:Contrast Media; D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D004280:Dobutamine; D004176:Dipyridamole; D013667:Technetium; D005682:Gadolinium