Abstract #2297

RAFF Contrast During Gene Therapy of Rat Brain Tumors: Association with Cell Density in Tissue Undergoing Apoptotic Cell Death

Timo Liimatainen¹, Alejandra Sierra-Lopez², Timothy Hanson³, Dennis J. Sorce¹, Michael Garwood¹, Shalom Michaeli¹, Olli Grhn²

¹Center for Magnetic Resonance Research, Dept. of Radiology, University of Minnesota, Minneapolis, MN, USA; ²A.I.Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland; ³Department of Biostatistics, University of Minnesota, Minneapolis, MN, USA

We studied an applicability of recently developed method called relaxation along fictitious field (RAFF) for detection of apoptotic cell death in a rat glioma gene therapy model. We demonstrated that using RAFF method the relaxation times can be reliably measured using different orientations of the fictitious field relative to the rotating frame of reference in vivo. The associations between RAFF relaxation time and trace of water diffusion tensor were found to show similar trend as continuous-wave spin-lock experiments. Measurements with RAFF associated with cell density in investigated tumor regions indicating high sensitivity of RAFF for small alterations in cell density.