Dose comparison of single- vs. double-dose in contrast-enhanced magnetic resonance angiography of the carotid arteries: Intraindividual cross-over blinded trial using Gd-DTPA

Purpose: To compare the intraindivldual differences of single-dose (D _s) and double-dose (D_D) gadolinium diethylene-triamine pentaacetic acid (Gd-DTPA)-enhanced magnetic resonance angiography (MRA) in the carotid arterial territory, an open-label single-center trial with blinded evaluations by two independent radiologists was undertaken. Materials and Methods: A total of 11 healthy volunteers were included in the study. Carotid MRAs were carried out in a 1.5 T clinical scanner using a neurovascular phased-array coil. Images were acquired with three-dimensional (3D) fast spoiled gradient recalled echo (FSPGR) sequence. Contrast agent was injected with a power injector, keeping the injection time constant for D_S and D _D. Results: Both readers found at least 97% of vascular segments evaluable. Median overall image quality and diagnostic confidence were rated excellent and confident to very confident. No statistically significant difference between the dosage groups could be demonstrated. Variability based on a region of interest (ROI) signal intensity (SI) measurement was 7% for the D_S and 5% for the D_D group. SI, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were significantly higher for the D_D group. Conclusion: Our results demonstrate that while a double dosing of contrast agent does increase SNR, it does not lead to further improvement in visual and perceptual image quality. A single dosage of approximately 0.1 mmol/kg body weight (bw) Gd-DTPA may be the preferable dosage in the carotid arteries.