Comparative evaluation of gadoteridol versus gadopentetate dimeglumine for contrast-enhanced MRI in a rat brain glioma model at 1.5 and 3.0 T

Objective: To compare gadoteridol and gadopentetate dimeglumine (Gd-DTPA) with respect to lesion enhancement in a rat brain glioma model at 1.5 and 3.0 T. Methods: Glioma cells were injected into the brains of 42 male CDF (Fisher 344) rats through implanted cannula to create Glioma animal model. One week after implantation, all rats were randomly divided in to four groups which included 12,10, 10,10 rats. The comparisons included the contrast effect of gadoteridol versus gadopentetate dimeglumine at both 1.5 and 3.0 T. In addition, gadoteridol alone was evaluated by comparing the standard dose at both two field strengths and half dose at 3.0 T to a standard full dose at 1.5 T. Two MRI scans for different contrast agent injections were performed in each animal model with an interval of 24 hours. T₁-weighted images were analyzed pre-contrast and at five time points (1, 3, 5, 7 and 9 min) post-contrast with respect to lesion signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast enhancement (CE). Student t test was used for statistics. Results: The mean SNR, CNR, and CE were respectively 54.4 ± 3.2, 17.0 ± 3.3 and 20.8 ± 3.4 with gadopentetate dimeglumine versus 53.2 ± 3.2, 17.2 ± 3.1 and 20.8 ± 3.2 with gadoteridol at 1.5 T at every postcontrast time point (t = 2.247, 0.403, 0.076, P > 0.05). The mean SNR, CNR, and CE were respectively 94.8 ± 7.1, 38.0 ± 6.0 and 45.0 ± 6.3 with gadopentetate dimeglumine versus 95.5 ± 2.9, 37.2 ± 2.7 and 45.6 ± 2.8 with gadoteridol at 3.0 T (t = 0.303, 0.573, 0.357, P > 0.05). No statistically significant differences were found in these parameters between the two agents at any time point at either field strength. Standard dose gadoteridol demonstrated significant improvements in SNR (51.9 ± 3.0 at 1.5 T vs 86.1 ± 4.9 at 3.0 T), CNR (15.6 ± 3.0 at 1.5 T vs 27.4 ± 5.0 at 3.0 T) and CE (18.6 ± 3.0 at 1.5 T vs 37.3 ± 5.3 at 3.0 T) at 3.0 T as compared to 1.5 T at every time post-contrast (t = 36.227, 11.977, 17.106, P < 0.05). Statistically significant differences were found in the comparison of gadoteridol with standard full-dose at 1.5 T and half-dose at 3.0 T in terms of SNR (53.8 ± 1.6 at 1.5 T vs 72.2 ± 2.4 at 3.0 T, t = 31.503, P < 0.05) and CNR (17.7 ± 1.7 at 1.5 T vs 15.4 ± 2.4 at 3.0 T, t = 5.137, P < 0.05). No statistically significant difference was found in CE (20.3 ± 1.6 at 1.5 T vs 21.1 ± 2.4 at 3.0 T, t = 2.033, P > 0.05). Conclusions: Enhancement with gadoteridol and gadopentetate dimeglumine is not significandy different in the rat brain glioma model, whether these agents are compared at 1.5 or 3.0 T MRI. Imaging at 3.0 T with gadoteridol does provide statistically significant improved enhancement when compared to 1.5 T. The ability to image with half-dose gadoteridol at 3.0 T without detriment to lesion enhancement allows further reduction in theoretical risk and improvement of safety in contrast agent application.