The study's Aim relates to modeling the complex hydro- and hemodynamics of intracranial physiology-pathology. We hypothesize that current hydrocephalus models are over-simplistic and that shunt-induced hydrodynamics are better modeled based on ICP waveform characteristics and the application of novel dynamic models. Much of the data for this Aim will be passively recorded during the routine care of the patient. In essence, we are only adding noninvasive MRI studies and TCD (transcranial Doppler) studies.