"Amipaque （Metrizamide） CT Ventriculography"による第III脳室内嚢腫の診断

DIAGNOSIS OF III RD VENTRICULAR CYST WITH "AMIPAQUE (METRIZAMIDE) CT VENTRICULOGRAPHY"

I．はじめに

　現今のCTの開発により頭蓋内占拠物の診断は非常に容易になつたといえよう。また，CT scanの方法も単にplain scanを行なうのみならず，造影剤の静注によるcontrast enhancementにて，mass lesionの増強ならびにperifocal edemaなどをより明瞭にすることができ，そのnatureすら類推し得るようになりつつある。

　さらに，最近では安全性の高い非イオン性造影剤であるAmipaque （通称Metrzamide：Sterling-Winthrop，Sweeden）の応用^2,3,13,14）によるCT cisternographyでみられるようなventricular reflux,delayed clearance^6）および，periventricular edema^10,11）の状態さえ観察でき，またCT ventriculographyにより脳室系の腫瘍の診断がなされ得るようになつた。

The patient is a 17-year-old female. She was suffering from dwarfism, irregular menstruation andobesity. Out of the dwarfism, there were no other neurological abnormalities. The serious clinical examinations were performed, and the cerebral angiography and the CT scan demonstrated the findings of the obstructive hydrocephalus. Namely, enlarged IIIrd ventricle and small IVth ventricle were observed with routine CT scan. Because these findings on CT scan, we thought the hydrocephalus was based on the aqueductal stenosis.

The vertebral angiography showed stretched posterior medial choroidal arteries and compressed the basilar tip posteriorly and inferiorly. Moreover, the carotid-angiography demonstrated the following findings, unrolling of the anterior cerebral arteries laterally stretched bilateral lenticulostriate arteries laterally shifted sylvian groups of the middle cerebral arteries, and stretched bilateral internalcerebral veins. Judging from that angiographic findings and CT scan, we thought there would be cystic tumor in the IIIrd ventricle. However, we suspected the IIIrd ventricular tumor, we were not able to differentiated it from the enlarged IIIrd ventricle itself exactly. Because, it's density in CT scan was equalled with that the cerebrospinal fluid.

According to above facts, we performed "Amipaque CT ventriculography through the ven-tricular catheter after V-P shunt.

By" the Amipaque CT ventriculography " we found exactly there was large cystic tumor in the IIIrd ventricle.

Their manifestation and some differential diag-nosis were disussed.