Noninvasive monitoring of tumor growth in a rat glioma model: comparison between neurological assessment and animal imaging.

Malignant gliomas are the most common primary tumors that arise from glial cells and are characterized by extensive invasiveness and rapid progression. Limitation of the current therapeutic regimen for malignant glioma warrants the development of new therapies strategies. In order to investigate new methods of therapy, establishment of a reliable animal model is essential both in studying the tumor biology and trialing a new therapeutic strategy. Noninvasive monitoring of tumor growth in living animals may be important for new therapeutic strategy development. The development of animal imaging techniques has improved our ability to investigate animal models of malignant gliomas. In this study, both neurological examination and positron emission tomography (PET) with (18)F-FDG were used to monitor tumor growth in a rat glioma model. Visual limb placing, tactile limb placing, and beam walking tests were used to assess neurological deficits. Neurobehavioral alterations were correlated with PET findings and histopathological data. Seven days after surgery, the tumor was clearly visible on PET images. Results of behavioral tests correlated well with imaging data and histopathological findings. PET is feasible to detect experimental rat gliomas in their early stage of development. In contrast, standard neurological assessment is useful for monitoring tumor growth during the course of the disease.