Purpose: To examine dose reduction comparing enhancement with full-dose gadopentetate dimeglumine (0.1 mmol/kg) to half-dose gadobenate dimeglumine in a rat brain glioma model. Materials and Methods: Intra-axial parenchymal brain tumors were implanted in 17 experimental animals. The 13 surviving animals were imaged at 1.5 or 3 T. Either gadopentetate dimeglumine or gadobenate dimeglumine was injected in random order on consecutive days. Tumor signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast enhancement (CE) for each agent were obtained with region of interest analyses and compared. Lesions were confirmed histopathologically. Results: Statistically significantly lower SNR, CNR, and CE parameters were found at both 1.5 and 3 T with half-dose gadobenate dimeglumine relative to full-dose gadopentetate dimeglumine (P < 0.05). SNR on average at 3 T was 70.0 +/- 14.4 for gadopentetate dimeglumine and 57.0 0 +/- 4.8 for gadobenate dimeglumine (P < 0.02). Conclusion: Improved r1 relaxivity with gadobenate dimeglumine does not produce adequate half-dose contrast-enhancement relative to full-dose gadopentetate dimeglumine. J. Magn. Reson. Imaging 2013;38:306-311. (c) 2012 Wiley Periodicals, Inc.