Three-dimensional multiphase time-resolved low-dose contrast-enhanced magnetic resonance angiography using TWIST on a 32-channel coil at 3 T: a quantitative and qualitative comparison of a conventional gadolinium chelate with a high-relaxivity agent.

Purpose: To evaluate low-dose contrast-enhanced magnetic resonance angiography (CE-MRA) at high temporal and spatial resolution for imaging of abdominal vascular structures.
Materials and Methods: Contrast-enhanced magnetic resonance angiography (TWIST [time-resolved angiography with interleaved stochastic trajectories]) was performed in 8 male New Zealand white rabbits at 3 T using a prototype 32-channel coil. Gadoteridol (Gd-HP-DO3A, ProHance; Bracco Imaging SpA, Milan, Italy) and the high-relaxivity agent gadobenate dimeglumine (Gd-BOPTA, MultiHance; Bracco Imaging SpA), each at a dose of 0.04 mmol/kg body weight, were used in an intraindividual comparison. Quantitative analysis of contrast-to-noise ratio (CNR) was performed in regions of interest placed in the aorta and the adjacent tissues. The image quality in the aorta, external iliac artery, and vena cava was categorized by 2 independent blinded readers from excellent (1) to poor (3).
Results: A significantly (P < 0.001) higher CNR was obtained with gadobenate dimeglumine. The improved CNR led to a better delineation of the external iliac arteries. Qualitative rating showed the image quality to be excellent for gadobenate dimeglumine and adequate for gadoteridol.
Conclusions: Time-resolved CE-MRA performed at 3 T with a 32-channel volume coil can be improved using the high-relaxivity agent gadobenate dimeglumine, which increases quality and quantity of vessel enhancement.