Andre Obenaus1,2, Stephan Ashwal3, Jerome Badaut Badaut3
1Radiation Medicine, Loma Linda University, Loma Linda, CA, United States; 2Radiology, Loma Linda University, Loma Linda , CA, United States; 3Pediatrics, Loma Linda University, Loma Linda, CA, United States
Diffusion weighted MRI is widely used in clinical diagnosis. To date the underlying molecular mechanism responsible for changes in the apparent diffusion coefficient (ADC) are poorly understood. Using small interference RNA directed against the astrocytic water channel, acqueporin-4 (AQP4), we were able to demonstrate a 50% decrease in ADC values when AQP4 expression was silenced (25%). Thus, astrocytic AQP4 contributes significantly to the ADC values in normal rodent brain. These results suggest new possibilities for interpreting ADC values in normal brain and under pathological conditions.