The case of a patient with predominant short-term memory and CT pattern suggestive of of normal pressure hydrocephalus, is discussed. Clinical and CT findings did not allow to predict the clinical response to a possible ventriculoperitoneal shunt. On MRI more accurate morphological evaluation with cine-MR functional assessment was obtained. Calculated CSF flow indexes evidenced hyperdynamia usually associated with a good outcome after ventriculoperitoneal shunting.