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 concentration 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 signal 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 sequences (flip angle was 60 degrees or 90 degrees). Using a high magnetic field apparatus, signal intensity linearly correlated with the concentration of Gd-DTPA between 0 and 2.0 or 3.0 mumol/g under spin echo or gradient-echo sequences. 2. Gd-DTPA concentration of the renal cortex ranged from 0.132 to 0.152 mumol/g tissue at 5 min after intravenous injection 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 cancer and prostatic cancer. Seven of them showed normal renal function and the other had renal insufficiency (GFR 25 ml/min/1.48 m2). Gd-DTPA concentrations of renal medulla and renal cell cancer tissue were 0.123 and 0.108 mumol/g tissue, respectively, at 5 min after intravenous injection of Gd-DTPA 0.05 mmol/kg body weight. These results suggest that the signal intensity of renal cortex, renal medulla, and renal cell cancer tissue may linearly correlate with Gd-DTPA concentration of tissues at 5 min after intravenous injection of Gd-DTPA 0.5 mmol/kg body weight.