“…These reports are based on either a subgroup of patients with a distinct intracranial localization or age distribution, 4,[9][10][11][16][17][18][22][23][24]26,33,39,43,[48][49][50][51]54,56,58,64,68,70,71,74,75,78,80,90 a relatively small number of patients, 15,19,25,31,32,45,52,55,60,62,72,76,77,89 or the inclusion of patients from before the computerized imaging era. 21,66,67 Furthermore, in most reports there is no information on whether the study is population based.…”