Effect of Gd-DTPA-BMA on blood and myocardial T1 at 1.5T and 3T in humans.
OBJECTIVE
To compare T(1) values of blood and myocardium at 1.5T and 3T before and after administration of Gd-DTPA-BMA in normal volunteers, and to evaluate the distribution of contrast media between myocardium and blood during steady state.


METHODS
Ten normal subjects were imaged with either 0.1 mmol/kg (N = 5) or 0.2 mmol/kg (N = 5) of Gd-DTPA-BMA contrast agent at 1.5T and 3T. T(1) measurements of blood and myocardium were performed prior to contrast injection and every five minutes for 35 minutes following contrast injection at both field strengths. Measurements of biodistribution were calculated from the ratio of DeltaR(1) (DeltaR(1myo)/DeltaR(1blood)).


RESULTS
Precontrast blood T(1) values (mean +/- SD, N = 10) did not significantly differ between 1.5T and 3T (1.58 +/- .13 sec, and 1.66 +/- .06 sec, respectively; P > 0.05), but myocardium T(1) values were significantly different (1.07 +/- .03 sec and 1.22 +/- .07 sec, respectively; P < 0.05). The field-dependent difference in myocardium T(1) postinjection (T(1)@3T - T(1)@1.5T) decreased by approximately 72% relative to precontrast T(1) values, while the field-dependent difference of blood T(1) decreased only 30% postcontrast. Measurements of DeltaR(1myo)/DeltaR(1blood) were constant for 35 minutes postcontrast, but changed between 1.5T and 3T (0.46 +/- .06 vs. 0.54 +/- .06, P < 0.10).


CONCLUSIONS
T(1) is significantly longer for myocardium (but not blood) at 3T compared to 1.5T. The differences in T(1) due to field strength are reduced following contrast administration, which may be attributed to changes in DeltaR(1myo)/DeltaR(1blood) with field strength.
Sharma
Puneet
P
Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA. Pun_23@yahoo.com
Socolow
Josh
J
Patel
Salil
S
Pettigrew
Roderic I
RI
Oshinski
John N
JN
D000328:Adult; D000704:Analysis of Variance; D003287:Contrast Media / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003326:Coronary Circulation; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009206:Myocardium; D019047:Phantoms, Imaging
D003287:Contrast Media; D019786:Gadolinium DTPA