Improved evaluation of myocardial perfusion and viability with the magnetic resonance blood pool contrast agent p792 in a nonreperfused porcine infarction model.
OBJECTIVE
To investigate whether a magnetic resonance (MR) blood pool contrast agent enables both evaluation of myocardial perfusion and viability in nonreperfused infarction in pigs.


METHODS
An optimized MR protocol using the blood pool contrast agent P792 (0.026 mmol/kg, twice the clinical dose, Guerbet, France) was investigated to evaluate nonreperfused myocardial infarction in an animal model. P792 was compared with the extracellular contrast agent Gd-DOTA (0.1 mmol/kg). The MRI findings were compared with histomorphometry performed with microspheres to evaluate perfusion and triphenyltetrazolium chloride (TTC) to evaluate viability. Contrast-enhanced MR imaging of the heart was performed on a 1.5-Tesla scanner 2 days after instrumentation in 6 minipigs. A saturation recovery steady-state free precession sequence was used for perfusion imaging and an inversion recovery fast low-angle shot sequence for evaluation of myocardial viability.


RESULTS
P792 tended to depict areas of reduced perfusion more accurately than Gd-DOTA (17.2% +/- 11.1% versus 13.7% +/- 8.0%) in comparison to the gold standard of histomorphometry with microspheres (18.2% +/- 9.8%). Moreover, P792, but not Gd-DOTA, depicted ischemic areas for 30 minutes after intravenous injection. The change in myocardial signal intensity during first pass was not significantly different after P792 compared with Gd-DOTA (140.3% +/- 64.4% versus 123.3% +/- 22.5%, P = 0.56). P792 was highly accurate in depicting infarcted areas (11.1% +/- 7.1%) compared with Gd-DOTA (12.1% +/- 8.2%, r = 0.98, P < 0.001) and histomorphometry with TTC (12.2% +/- 8.0%, r = 0.99, P < 0.001).


CONCLUSIONS
Unlike Gd-DOTA, the blood pool contrast agent P792 allows evaluation of myocardial perfusion for a period of 30 minutes and shows good agreement with histomorphometry. P792 must be examined in further studies to evaluate its potential in evaluating early myocardial lesions and reperfusion. In addition, P792 also allows for evaluation of myocardial viability.
Peukert
Daniel
D
Department of Radiology, Freie Universität und Humboldt-Universität zu, Berlin, Germany.
Kaufels
Nicola
N
Laule
Michael
M
Schnorr
Jörg
J
Carme
Sabin
S
Farr
Thomas
T
Schönenberger
Eva
E
Taupitz
Matthias
M
Hamm
Bernd
B
Dewey
Marc
M
D000818:Animals; D003287:Contrast Media; D006571:Heterocyclic Compounds / Q000008:administration & dosage*; D008279:Magnetic Resonance Imaging; D023421:Models, Animal; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology; D009206:Myocardium; D009942:Organometallic Compounds / Q000008:administration & dosage*; D010477:Perfusion; D013552:Swine; D013778:Tetrazolium Salts; D013997:Time Factors
D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D013778:Tetrazolium Salts; C009591:triphenyltetrazolium; C435266:contrast agent P792