Brain imaging in drug R&D

FDG-PET imaging for the evaluation of antiglioma agents in a rat model

The increasing development of novel anticancer agents demands parallel advances in the methods used to rapidly assess their therapeutic efficacy (TE) in the preclinical phase. We evaluated the ability of small-animal PET, using the (18)F-fluoro-deoxy-D-glucose (FDG) radiotracer, to predict the TE of a number of anticancer agents in the rat C6 glioma model following 3 days of treatment. Semi-quantitative measurements of changes in FDG uptake during the course of treatment (standardized uptake value response [SUV(r)]) were found to be significantly lower in tumors treated with the hypoxia-inducible factor-1alpha inhibitor YC-1 (15 mg/kg) than in tumors in the control group. No significant SUV(r) change was observed following a similar 3-day regimen with the proapoptotic agent NS1619 (20 microg/kg), the combination of YC-1 and NS1619, or the alkylating agent temozolomide (7.5 mg/kg). Quantitative immunohistochemical studies demonstrated significantly lower levels of glucose transporter-1 (GLUT-1) expression in the YC-1-treated tumors, thereby correlating with the low SUV(r) observed in this group. The ability of SUV(r) to predict gold-standard outcomes of TE was further validated as YC-1-treated tumors had decreased volumes compared to control tumors. As such, we successfully demonstrated the ability of FDG-PET to rapidly determine the TE of novel agents for the treatment of glioma in the preclinical phase of evaluation.

Towards multimodal atlases of the human brain

Atlases of the human brain have an important impact on neuroscience. The emergence of ever more sophisticated imaging techniques, brain mapping methods and analytical strategies has the potential to revolutionize the concept of the brain atlas. Atlases can now combine data describing multiple aspects of brain structure or function at different scales from different subjects, yielding a truly integrative and comprehensive description of this organ. These integrative approaches have provided significant impetus for the human brain mapping initiatives, and have important applications in health and disease.