CTによる正常脳室および脳溝の加齢現象についての検討

EVALUATON OF THE CEREBRAL VENTRICULAR SYSTEM AND CORTICAL SULCI ASSOCIATED WITH AGING ON CT

　抄録　正常の脳室の大きさ，および脳溝の数と幅についてCT上で測定し，その加齢現象について検討した。対象は16歳以上の正常と思われる258例（平均年齢42.9歳）で，筑波脳神経検査センターでCT検査をうけた15,677例の中から抽出された。脳室については第4脳室，第3脳室，側脳室の幅を測定し，頭蓋骨内板間距離の比を求め，脳溝については脳溝の描出頻度を皮質の部位別に観察し，また脳溝最大幅を実際値に換算して測定した。得られた値を各年代間で検定を行って比較検討した。結果は，第4脳室幅は20歳代に比して30歳代で増加したが，その後は変化しなかった。第3脳室幅は視床下部レベルでは20歳代に比し，30歳代で増加し，視床レベルでは40歳代に比し50歳代で増加したが，その後は共に変化しなかった。側脳室幅は加齢と共に増加したが，特に40歳代に比して50歳代で著明に増加した。脳溝の数は加齢と共に増加し，特に60歳代では50歳代に比し著明に増加した。脳溝のCT上での描出開始は，frontalでは10歳代に，centralでは20歳代に，parietalとoccipitalでは30歳代に起った。脳溝の幅は40歳未満では全て4.5mm以下であった。40歳以上は加齢と共に増加するが，全て6.2mm以下であった。

This study was attempted to establish a relation-ship between normal values and aging process of cerebral ventricular size and cortical sulci on computed tomography. A total of two hundred and fifty-eight cases of 126 males and 132 females was selected from 15, 677 cases who received CT-examination at Tsukuba Neurological Examina-tion Center in Ibaraki, Japan since 1978 to 1980.

Patients with both medical and neurological dis-orders (as following : cerebrovascular disease, mas staking lesion, head trauma, congenital ano-maly, seizure, dementia, psychosis, hypertension, diabetes mellitus, heart and pulmonary disease and other systemic illness) were excluded.

These subjecst aged from 16 ys to 81 ys (mean age was 42) and their commonest complaints were headache.

The 258 subjects were classified into 8 groups according to age. The ventricle-width and number and width of the cortical sulci were measured on CT. Statistical analysis was performed using t test in each group.

The results were obtained as following:

1) The width of the fourth ventricle increased significantly in the fourth decade comparing with in the third decade.

2) The width of the third ventricle increased significantly in the fourth decade compaing with in the third decade at the hypothalamic level and also in the sixth decade comparing with in the fifth decade at the thalamic level.

3) The width of the anterior horn and the body of the lateral ventricles increased gradually with age, and showed a significant increase in the sixth decade comparing with in the fifth decade.

4) The number of cortical sulci increased grad-ually with age, and increased significantly in the seventh decade comparing with in the sixth de-cade, especially in the occipital areas.

The cortical sulci started to appear initially inthe frontal areas during the second decade, subseq-uently in the central during the third decade and finally in both the parietal and occipital areas during the fourth decade.

5) The width of the cortical sulciwas less than 4.5 mm under the fifth decade. It did not exeed 6.2 mm in all of the cases, though widening grad-ually with age over the fifth decade.