Magnetic resonance imaging of patched heterozygous and xenografted mouse brain tumors.

Experimental mouse models are emerging as useful systems for the study of human brain tumors. Nuclear magnetic resonance imaging (MRI) methods can noninvasively provide images of complex heterogeneous tissues such as experimental brain tumors. The current report demonstrates the feasibility of longitudinal high-resolution MRI in two mouse brain tumor models: patched heterozygous (ptc +/-) mice with spontaneously arising posterior fossa tumors that resemble human medulloblastoma, and homozygous nude mice implanted with intracerebral xenografts of human medulloblastoma cell lines. Methods were optimized to achieve favorable volumetric comparison with histologic methods and sub-millimeter resolution, improved by contrast enhancement with intravenous administration of a gadolinium-based agent. Results also show that experimental mice, even symptomatic mice, tolerate repeated serial imaging studies over weeks to months to follow tumor progression and to visualize placement of an intracerebral drug delivery system.