Abstract #1708

Hyperammonemia and Edema: A DTI Study in the Adult Rat Brain

Nicolas Kunz^1,2, Cristina Cudalbu¹, Yohan Van de Looij^1,2, Petra Hppi², Stephane Sizonenko², Rolf Gruetter^1,3

¹Laboratory of functional and metabolic imaging (LIFMET), Ecole Polytechnique Fdrale de Lausanne, Lausanne, Switzerland; ²Division of Child Growth &Development, University of Geneva, Geneva, Switzerland; ³Department of Radiology, University of Geneva & Lausanne, Geneva & Lausanne, Switzerland

Ammonia is a neurotoxin that is implicated in the pathogenesis of hepatic encephalophaty, which is reported to be responsible for brain edema. It is not yet clear whether brain edema is mostly vasogenic or cytotoxic. The aim of this study was to assess the effects of hyperammonemia on the rat brain by using DTI at 9.4T. This study shows a rapid increase of the ventricle size during the three first hours of infusion along with a decrease in ADC. As the ventricle size gets stabilized after 6h, the ADC keeps on decreasing, indicating the formation of mild cytotoxic edema.