Contrast induced myocardial signal reduction: effect of lanthanide chelates on ultra high speed MR images.
The myocardial MR signal reduction associated with an intravenous bolus of Gd-DTPA and Dy-DTPA was studied in a canine model. Imaging was performed with a high speed echo-planar type imaging system (Instascan, Advanced NMR Systems, Inc.). Gated spin-echo images were obtained with TE of 30 ms, which permits image acquisition in approximately 40 ms. The gated TR was dependent on the heart rate, with an average TR of 2.4 s. After 0.1 mmol/kg of contrast was injected, 70 images were acquired, which showed in an 80-image data set a reduction in myocardial signal with a gradual return to normal. After dipyridamole infusion, the signal loss was significantly more pronounced, and earlier than in the control data set. There was no significant difference between Gd-DTPA and Dy-DTPA in these imaging studies despite the theoretical prediction of better Dy signal reduction, possibly due to physiological variability during the course of a study or between studies. The cause of enhanced contrast effect after dipyridamole infusion is discussed, as is the basis for dipyridamole enhancement, and the possible role of contrast enhanced MR imaging in the detection of cardiac disease.
Kantor
H L
HL
Cardiac Unit, Massachusetts General Hospital, Boston 02114.
Rzedzian
R R
RR
Buxton
R
R
Berliner
E
E
Beaulieu
P
P
Rosen
B
B
Brady
T J
TJ
Pykett
I L
IL
D000818:Animals; D004176:Dipyridamole / Q000494:pharmacology; D004285:Dogs; D019786:Gadolinium DTPA; D006321:Heart / Q000033:anatomy & histology*; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008674:Metals, Rare Earth; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives*
D008674:Metals, Rare Earth; D009942:Organometallic Compounds; D004176:Dipyridamole; D004369:Pentetic Acid; C055865:dysprosium DTPA; D019786:Gadolinium DTPA