The signal enhancement (SE) and enhancement kinetics of gadolinium-based contrast agents (GBCAs) in T1-weighted magnetic resonance (MR) images depend on the relaxivity of the GBCA and its pharmacokinetic profile. This in vivo study systematically compared the SE (technical efficacy) and the enhancement kinetics of the 3 macrocyclic GBCAs gadobutrol, gadoteridol, and gadoterate meglumine in various body regions.
Materials and Methods
A total of 15 healthy male white New Zealand rabbits were randomly divided into 3 groups (n = 5/group). The GBCAs were injected intravenously (0.1 mmol/kg body weight) and signal intensities from multiphase T1-weighted MR images (1.5 T; volumetric interpolated breath-hold examination (VIBE); repetition time/echo time/α: 4.74 milliseconds/2.38 milliseconds/10°) before and up to approximately 23 minutes after contrast injection were determined in the brain, tongue, submandibular gland, liver, spleen, prostate, muscle, and blood/aorta). Thirty minutes after injection, the animals were sacrificed and Gadolinium (Gd) concentrations were determined in the above-mentioned tissue samples by inductively coupled plasma optical emission spectrometry. Gadolinium tissue concentrations were correlated with the respective SE measurements in each tissue.
The time course of SE, representing the pharmacokinetic profile of the GBCA, was similar for all 3 agents in all tissues. The magnitude of SE was, however, tissue dependent and consistently higher for gadobutrol (P < 0.05 in all tissues but brain). No significant difference in the magnitude of SE was found between gadoteridol and gadoterate meglumine. The inductively coupled plasma optical emission spectrometry analysis revealed no differences in Gd-tissue concentrations between the GBCAs. A linear correlation was observed between SE and the respective Gd concentrations for all 3 GBCAs. A significantly higher enhancement efficacy, that is, SE per Gd concentration, was observed for gadobutrol.
Gadobutrol-enhanced MR imaging showed greater SE compared with gadoteridol and gadoterate meglumine, whereas the SE kinetics were similar among the 3 GBCAs. For all 3 GBCAs, the SE was independent of the body region.