Age-dependent differences of distribution and clearance patterns in normal RIHSA cisternograms.

In a retrospective study of 536 unselected consecutive RIHSA cisternographies a total of 84 cases with normal time-sequential scans were reviewed and, after dividing into three age groups, statistically elaborated with regard to the CSF pathways and flow rate. Our findings on a 5% level of significance are: 1) The total CSF flow and turnover depends on age; the highest rate of CSF flow is found in young patients (less than 25 years) and decreases constantly with increasing age. 2) In old patients (less than 50 years) the dorsal and lateral CSF pathways predominate over the frontomedial ones which are preferred in the younger age group (less than 25 years). 3). The washout of the basal cisterns and the clearance of the isotope over the convexities decreases significantly with increasing age. 4) The normal individual cisternographic variations and significant age-dependent differences agree with simultaneous encephalographic findings.