Characterization of a gadolinium-labeled cholesterol derivative as an organ-specific contrast agent for adrenal MR imaging.
The purpose of the study was to determine if derivatization of cholesterol with a paramagnetic label could result in an organ-specific contrast agent for magnetic resonance imaging of the adrenal glands. Gadolinium-DO3A-labeled cholesterol was synthesized and the relaxivities in water and blood plasma determined at 0.47 T and 40 degrees C. Organ distribution was measured at 2 (n = 2) and 24 (n = 2) hours after intravenous injection of a 50 mumol/kg dose of Gd-DO3A-cholesterol in rats weighing 220-240 g. T1-weighted spin-echo images were acquired at 2 T before and after injection of 50 mumol/kg Gd-DO3A-cholesterol (n = 2) and Gd-DTPA (diethylenetriaminepentaacetic acid)-albumin (n = 2). More than 99% of the Gd-DO3A-cholesterol was found to be protein bound in bovine serum. High T1 and T2 relaxivities were found in water and plasma. High tissue concentrations of Gd-DO3A-cholesterol were found only in adrenal glands and liver. At 24 hours, adrenal gadolinium concentrations were about 10 times higher than in blood. At 2 hours after injection of Gd-DO3A-cholesterol, enhancement was 162% in adrenal glands and 146% in liver. With Gd-DTPA-albumin, enhancement values were 57% and 56%, respectively.
Mühler
A
A
MRI Contrast Media Research, Schering AG Berlin, Germany.
Platzek
J
J
Radüchel
B
B
Frenzel
T
T
Weinmann
H J
HJ
D000311:Adrenal Glands / Q000033:anatomy & histology*; D000818:Animals; D002784:Cholesterol; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D008279:Magnetic Resonance Imaging; D051381:Rats; D017208:Rats, Wistar
D003287:Contrast Media; D002784:Cholesterol; D005682:Gadolinium