[CT evaluation of cerebellar atrophy with aging in healthy persons].

The author studied the incidence of computed tomographic evidences of cerebellar atrophy in 2,102 neurologically normal subjects. The subjects were selected from approximately 10,000 cases who underwent CT examination at Juntendo University hospital since April 17, 1978 to October 30, 1979. The 2,102 subjects were classified into 10 groups according to their age, as following: 1) below the age of 1 year, 2) between 1 and 4 years, 3) between 5 and 9 years, 4) second decade, 5) third decade, 6) fourth decade, 7) fifth decade, 8) sixth decade, 9) seventh decade, 10) after the age of seventy. The incidence of enlarged cerebellar vermis fissures, cerebellar hemispheric fissures, subarachnoid space around the cerebellum and the fourth ventricle were explored on CT. As regards the fourth ventricle, the maximum transverse width of the fourth ventricle and the maximum inside diameter of the posterior fossa were measured on CT, and ratio of the width of the fourth ventricle against the diameter of the posterior fossa were calculated. Statistical analysis was performed using chi 2 test or t test in each age group. The results obtained were as following: I. The incidence of enlarged cerebellar vermis fissures and cerebellar hemispheric fissures increased gradually with aging. Though the difference were almost significant in any groups older than 20 years. It was noteworthy among those who were older than 60 years. II. The incidence of enlarged subarachnoid space around the cerebellum also increased significantly after the age of sixty, III. In subjects older than twenty, the width of the fourth ventricle increased with aging.(ABSTRACT TRUNCATED AT 250 WORDS)