Abstract
In 54 of 80 infratentorial tumors, neurological as well as radiographical signs of transtentorial upward herniation was investigated.
The radiological findings were classified into three types; Cerebellar Types, Brain Stem Type, Total Type.
Computerized tomography (CT) was performed in 16 of 80 infratentorial tumors.
These CT findings were compared with the each type of radiographical transtentorial upward herniation.
It was shown that the quadrigeminal cistern was obstructed early in cerebellar tumor which was apt to show the Cerebellar Type of the transtentorial upward herniation.
On the contrary, the cistern was not obstructed until terminal stage in pontine tumor which was apt to show the Brain Stem Type.
In cerebello-pontine angle tumor, the quadrigeminal cistern was obstructed asymmetrically, the tumor side was dilatated and the other side was obstructed, which was due to midbrain shift to the contralateral side.
In conclusion, the following interpretation is reasonable. Quadrigeminal cistern is easily obstructed by upward displacement of the cerebellum and lateral displacement of the midbrain, whereas, it rarely changes its configuration by upward displacement of the brain stem.
However, we could not find any correlation between radiological and neurological signs in regards to upward herniation.
It can be said that the progress of radiological transtentorial upward herniation is correlated with neither local pressure nor local cerebral blood flow.
