CONCENTRATION OF GADOLINIUM-DIETHYLENE TRIAMINE PENTAACETIC ACID IN HUMAN KIDNEY - STUDY ON PROPER TIME FOR DYNAMIC MAGNETIC-RESONANCE-IMAGING OF THE HUMAN KIDNEY ON LOW AND HIGH MAGNETIC-FIELDS

Although Gadolinium diethylene triamine pentaacetic acid (Gd-DTPA) has been used as a contrast material in magnetic resonance imaging, it is known that contrast enhancement effect disappears if the concentratio n of Gd-DPTA increases beyond some levels. In this study, to evaluate the proper pulse sequences for dynamic magnetic resonance imaging (MRI ) in the human kidney, the concentration of Gd-DTPA was quantitatively measured by inductively coupled plasma (ICP) emission spectrometry in human biological samples after administration of Gd-DTPA, and the sig nal intensity of MRI is the solutions of several concentrations of Gd- DTPA was measured. The results were; 1. In using a low magnetic field apparatus, signal intensity linearly correlated with the concentration of Gd-DTPA between 0 and 2.0 mumol/g under saturation recovery sequen ces (flip angle was 60-degrees or 90-degrees). Using a high magnetic f ield apparatus, signal intensity linearly correlated with the concentr ation of Gd-DTPA between 0 and 2.0 or 3.0 mumol/g under spin echo or g radient-echo sequences. 2. Gd-DTPA concentration of the renal cortex r anged from 0.132 to 0.152 mumol/g tissue at 5 min after intravenous in jection of Gd-DTPA 0.05 mmol/kg body weight in 7 patients with adrenal tumor or renal cell cancer, and 1 patient with both urinary bladder c ancer and prostatic cancer. Seven of them showed normal renal function and the other had renal insufficiency (GFR 25 ml/min/1.48 m2). Gd-DTP A concentrations of renal medulla and renal cell cancer tissue were 0. 123 and 0.108 mumol/g tissue, respectively, at 5 min after itravenous injection of Gd-DTPA 0.05 mmol/kg body weight. These results suggest t hat the signal intensity of renal cortex, renal medulla, and renal cel l cancer tissue may linearly correlate with Gd-DTPA concentration of t issues at 5 min after intravenous injection of Gd-DTPA 0.5 mmol/kg bod y weight.