Dose comparison of single versus double dose in contrast-enhanced magnetic resonance angiography of the renal arteries: intra-individual cross-over blinded trial using Gd-DTPA.

This study was planned as an open-label, single-centre trial with blinded evaluations by two independent radiologists, aimed at the intra-individual comparison of single-dose and double-dose Gd-DTPA-enhanced MRA in the renal arterial territory. Ten healthy volunteers were included in the study. Renal MRAs were carried out on a clinical 1.5-T MR system using a body phased-array coil. Images were acquired with three-dimensional fast spoiled gradient echo sequence. Contrast agent was injected with a power injector keeping the injection time constant for single dose and double dose. Both readers found at least 96% of vascular segments evaluable. Median overall image quality was rated excellent, and diagnostic confidence was rated confident. No statistically significant difference between the dosage groups could be demonstrated. Signal intensity, SNR and CNR were significantly higher for the double-dose group. Our results demonstrate that while a double dose of contrast agent increases SNR, it does not lead to further improvement in visual and perceptual image quality. A single dosage of approximately 0.1 mmol/kg bw Gd-DTPA may be the preferable dosage to demonstrate the renal arteries.