Quantification of MRI measured myocardial perfusion reserve in healthy humans: a comparison with positron emission tomography.
OBJECTIVE
To validate a noninvasive quantitative MRI technique, the K(i) perfusion method, for myocardial perfusion in humans using (13)N-ammonia PET as a reference method.


METHODS
Ten healthy males (64 +/- 8 years) were examined with combined PET and MRI perfusion imaging at rest and during stress induced by dipyridamole in order to determine the myocardial perfusion reserve. Myocardial and blood time concentration curves obtained by Gd-DTPA-enhanced MRI and (13)N-ammonia PET were fitted by a two-compartment perfusion model.


RESULTS
Mean perfusion values (+/-SD) derived from the MRI method at rest and at hyperemia were 80 +/- 20 and 183 +/- 56 mL/min/100 g, respectively. The same data for PET were 71 +/- 16 and 203 +/- 67 mL/min/100 g. A linear relationship was observed between MRI and PET-derived myocardial perfusion reserve for regional and global data. Linear regression for the global absolute perfusion reserve gave a correlation coefficient of 0.96 (P < 0.004, y=0.83x-6.9). A good agreement between the two methods to determine low or high perfusion reserves was found.


CONCLUSIONS
Our data provide validation of the perfusion marker K(i) derived by the MRI method as a quantitative marker for myocardial perfusion in healthy humans.
Fritz-Hansen
Thomas
T
Danish Research Center of Magnetic Resonance, Hvidovre Hospital, Hellerup, Denmark. thhan@geh.regionh.dk
Hove
Jens D
JD
Kofoed
Klaus F
KF
Kelbaek
Henning
H
Larsson
Henrik B W
HB
D000368:Aged; D000641:Ammonia; D003287:Contrast Media; D003326:Coronary Circulation; D005080:Exercise Test; D006801:Humans; D008279:Magnetic Resonance Imaging; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009590:Nitrogen Radioisotopes; D004369:Pentetic Acid; D049268:Positron-Emission Tomography
D003287:Contrast Media; D009590:Nitrogen Radioisotopes; D000641:Ammonia; D004369:Pentetic Acid