Brain MRI with single-dose (0.1 mmol/kg) gadobutrol at 1.5 T and 3 T: Comparison with 0.15 mmol/kg gadoterate meglumine

OBJECTIVE. The purpose of this article is to evaluate the efficacy of a single dose of gadobutrol (0.1 mmol/kg of body weight) compared with that of a substantially higher dose of gadoterate meglumine (0.15 mmol/kg of body weight) in a rat brain tumor model at 1.5 and 3 T. Materials and Methods. A cohort of 20 Fischer rats with a surgically implanted plastic brain cannula for glioma cell injection was divided into two groups. Group A underwent MRI at 1.5 T, and group B underwent MRI at 3 T. All rats were implanted with 10 μL of C6/lacZ glioma cells. Seven days after tumor cell implantation, MRI was performed with the first of two contrast agents in randomized order. Twenty-four hours later, MRI was performed with the second contrast agent. Both contrast agents were macrocyclic but differed in concentration. All rats were sacrificed after the second MRI scan was obtained, and brains were harvested for histopathologic assessment. For evaluation of image quality, signal-tonoise ratio, contrast-to-noise ratio, and lesion enhancement were evaluated. RESULTS. Two rats in each group died before the imaging protocol was completed. Thus, 16 rats could be evaluated. At both 1.5 and 3 T, no significant differences between the two contrast agents were found in terms of signal-to-noise ratio, contrast-to-noise ratio, and lesion enhancement, although the contrast agents were applied at substantially different dosages. CONCLUSION. The amount of gadobutrol needed to reach the same efficacy as gadoterate meglumine is substantially lower, which may be beneficial for patients with impaired renal function. In addition, increasing the dose of gadobutrol to 0.15 mmol/kg of body weight can potentially lead to better delineation of lesions.