Validation of MRI measurement of cardiac output in the dog: the effects of dobutamine and minoxidil.
The use of magnetic resonance imaging (MRI) for the measurement of cardiac output parameters in anesthetized adult male beagle dogs has been validated against a widely accepted thermodilution method. Using a multislice cine gradient echo MRI method to acquire images of the entire heart, left ventricular lumen volumes were measured at systole and diastole in seven animals. Cardiac output correlated well (R 2 = 0.88) with thermodilution measurements made in a parallel manner, both before and during acute stimulation with the inotrope dobutamine. In a chronic study of changes in cardiac morphology and function brought about by the antihypertensive minoxidil, MRI reliably detected the expected increases in stroke volume (28%) and cardiac output (58%) resulting from neural reaction to decreased blood pressure. Left ventricular lumen enlarged as well in response to fluid retention and plasma volume increase. Two in four minoxidil-treated animals also developed clear MRI-visible pericardial effusion.
Hockings
Paul D
PD
GlaxoSmithKline, The Frythe, Welwyn, Hertfordshire AL6 9AR, United Kingdom.
Busza
Albert L
AL
Byrne
Joanne
J
Patel
Bela
B
Smart
Sean C
SC
Reid
David G
DG
Lloyd
Heather L
HL
White
Alan
A
Pointing
Karen
K
Farnfield
Belinda A
BA
Criado-Gonzalez
Ana
A
Whelan
Greg A
GA
Taylor
Gemma L
GL
Birmingham
Jeffrey M
JM
Slaughter
Mark R
MR
Osborne
Janette A
JA
Krebs-Brown
Axel
A
Templeton
David
D